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In-press articles are listed online shortly after acceptance. Prepress abstracts are also made available. These have not yet been fully checked and copyedited and are therefore subject to change before actual publication. The article is however citable as "in press", using the DOI.

Feature Articles

N 1321 Hobday AJ, van Putten EI, Cvitanovic C, Dunlop M, Fossette S, Ison S, Richards SA, Thomas L, Tuohy P, Annand-Jones R, Tucker T, Whiting S Flatback futures—evaluating conservation interventions to reduce threats to an endemic Australian turtle Prepress abstract | Managing flatback turtles for the future

N 1322 Adhya T, Banerjee S, Dey P, Nanda S, Santra S, Nesha I Density estimation of the globally threatened fishing cat Prionailurus viverrinus through a participatory science approach in the Chilika lagoon, eastern India Prepress abstract

N 1324 Garrison LP, Soldevilla MS, Martinez A, Mullin KD A density surface model describing the habitat of the critically endangered Rice’s whale Balaenoptera ricei in the Gulf of Mexico Prepress abstract

N 1325 Farrell CE, Simard J, Louttit S, Southee FM, Cruz-Font L, Struthers DP, Seguin JL, O’Connor CM Occupancy, movement, and behaviour of namew (lake sturgeon, Acipenser fulvescens ) in an intact river in Canada Prepress abstract

N 1326 Richards SA, Cvitanovic C, Dunlop M, Fossette S, Thomas L, Tucker AD, van Putten EI, Whiting AU, Whiting SD, Hobday AJ Identifying impactful sea turtle conservation strategies: a mismatch between most influential and most readily manageable life-stages Prepress abstract | Managing flatback turtles for the future

N 1327 Indeck KL, Gehrmann R, Richardson AL, Barclay D, Baumgartner MF, Nolet V, Davies KTA Variation in glider-detected North Atlantic right, blue, and fin whale calls in proximity to high-traffic shipping lanes Prepress abstract

N 1328 Hernandez-Gonzalez A, Saavedra C, Read FL, López A, Gouveia A, Covelo P, Alonso-Fernández A, Velasco F, Santos MB, Pierce GJ Feeding ecology of harbour porpoises Phocoena phocoena stranded on the Galician coast (NW Spain) between 1990 and 2018 Prepress abstract

N 1329 Gonzalez Pestana A, Alfaro-Shigueto J, Velez-Zuazo X, Mangel JC Natural history, fisheries, and conservation of the Pacific guitarfish: signs of trouble in Peruvian waters Prepress abstract | Global status of wedgefish and guitarfish

N 1330 Wright AJ, Gabaldon J, Zhang D, Hamilton P Bimodal vertical distribution of right whales Eubalaena glacialis in the Gulf of St. Lawrence Prepress abstract

N 1331 Hazel J, Hamann M, Bell I, Groom R Occurrence of leatherback turtles around Australia Prepress abstract

N 1332 Medrano-González L, Audley K, Baker CS, Steel D mtDNA variation of humpback whales in their wintering grounds of Guerrero, southern Mexican Pacific Prepress abstract

N 1333 Matthews CJD, Longstaffe FJ, Parent GJ, Hornby CA, Watt CA Discriminating Canadian Arctic beluga management stocks using dentine oxygen and carbon isotopes Prepress abstract

N 1334 Evans S, Schulze MJ, Brown M, Mortimer JA Nesting female hawksbill sea turtles trending smaller in the western Indian Ocean Prepress abstract

N 1335 Hoff S, Mosher BA, Watson M, Johnson L, Olson E, O’Dell D, Pendergast CJ, Bogan DA, Herzog CJ, Turner WC Widespread occupancy of the Endangered northern myotis on northeastern Atlantic Coastal Plain islands Prepress abstract

N 1336 Parnell K, Merkens K, Huetz C, Charrier I, Robinson SJ, Pacini A, Bejder L Underwater soundscapes within critical habitats of the endangered Hawaiian monk seal: implications for conservation Prepress abstract

last update: April 25, 2024

Endangered Species

An endangered species is a type of organism that is threatened by extinction. Species become endangered for two main reasons: loss of habitat and loss of genetic variation.

Biology, Ecology, Geography, Conservation

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An endangered species is a type of organism that is threatened by extinction . Species become endangered for two main reasons: loss of habitat and loss of genetic variation . Loss of Habitat A loss of habitat can happen naturally. Nonavian dinosaurs , for instance, lost their habitat about 65 million years ago. The hot, dry climate of the Cretaceous period changed very quickly, most likely because of an asteroid striking Earth. The impact of the asteroid forced debris into the atmosphere , reducing the amount of heat and light that reached Earth’s surface. The dinosaurs were unable to adapt to this new, cooler habitat. Nonavian dinosaurs became endangered, then extinct . Human activity can also contribute to a loss of habitat. Development for housing, industry , and agriculture reduces the habitat of native organisms. This can happen in a number of different ways. Development can eliminate habitat and native species directly. In the Amazon rainforest of South America, developers have cleared hundreds of thousands of acres. To “clear” a piece of land is to remove all trees and vegetation from it. The Amazon rainforest is cleared for cattle ranches , logging , and ur ban use. Development can also endanger species indirectly. Some species, such as fig trees of the rainforest, may provide habitat for other species. As trees are destroyed, species that depend on that tree habitat may also become endangered. Tree crowns provide habitat in the canopy , or top layer, of a rainforest . Plants such as vines, fungi such as mushrooms, and insects such as butterflies live in the rainforest canopy. So do hundreds of species of tropical birds and mammals such as monkeys. As trees are cut down, this habitat is lost. Species have less room to live and reproduce . Loss of habitat may happen as development takes place in a species range . Many animals have a range of hundreds of square kilometers. The mountain lion ( Puma concolor ) of North America, for instance, has a range of up to 1,000 square kilometers (386 square miles). To successfully live and reproduce, a single mountain lion patrols this much territory. Urban areas , such as Los Angeles, California, U.S.A., and Vancouver, British Columbia, Canada, grew rapidly during the 20th century. As these areas expanded into the wilderness, the mountain lion’s habitat became smaller. That means the habitat can support fewer mountain lions. Because enormous parts of the Sierra Nevada, Rocky, and Cascade mountain ranges remain undeveloped, however, mountain lions are not endangered. Loss of habitat can also lead to increased encounters between wild species and people. As development brings people deeper into a species range, they may have more exposure to wild species. Poisonous plants and fungi may grow closer to homes and schools. Wild animals are also spotted more frequently . These animals are simply patrolling their range, but interaction with people can be deadly. Polar bears ( Ursus maritimus ), mountain lions, and alligators are all predators brought into close contact with people as they lose their habitat to homes, farms , and businesses. As people kill these wild animals, through pesticides , accidents such as collisions with cars, or hunting, native species may become endangered.

Loss of Genetic Variation Genetic variation is the diversity found within a species. It’s why human beings may have blond, red, brown, or black hair. Genetic variation allows species to adapt to changes in the environment. Usually, the greater the population of a species, the greater its genetic variation. Inbreeding is reproduction with close family members. Groups of species that have a tendency to inbreed usually have little genetic variation, because no new genetic information is introduced to the group. Disease is much more common, and much more deadly, among inbred groups. Inbred species do not have the genetic variation to develop resistance to the disease. For this reason, fewer offspring of inbred groups survive to maturity. Loss of genetic variation can occur naturally. Cheetahs ( Acinonyx jubatus ) are a threatened species native to Africa and Asia. These big cats have very little genetic variation. Biologists say that during the last Ice Age , cheetahs went through a long period of inbreeding. As a result, there are very few genetic differences between cheetahs. They cannot adapt to changes in the environment as quickly as other animals, and fewer cheetahs survive to maturity. Cheetahs are also much more difficult to breed in captivity than other big cats, such as lions ( Panthera leo ). Human activity can also lead to a loss of genetic variation. Overhunting and overfishing have reduced the populations of many animals. Reduced population means there are fewer breeding pairs . A breeding pair is made up of two mature members of the species that are not closely related and can produce healthy offspring. With fewer breeding pairs, genetic variation shrinks. Monoculture , the agricultural method of growing a single crop , can also reduce genetic variation. Modern agribusiness relies on monocultures. Almost all potatoes cultivated , sold, and consumed, for instance, are from a single species, the Russet Burbank ( Solanum tuberosum ). Potatoes, native to the Andes Mountains of South America, have dozens of natural varieties. The genetic variation of wild potatoes allows them to adapt to climate change and disease. For Russet Burbanks, however, farmers must use fertilizers and pesticides to ensure healthy crops because the plant has almost no genetic variation. Plant breeders often go back to wild varieties to collect genes that will help cultivated plants resist pests and drought, and adapt to climate change. However, climate change is also threatening wild varieties. That means domesticated plants may lose an important source of traits that help them overcome new threats. The Red List The International Union for Conservation of Nature (IUCN) keeps a “Red List of Threatened Species.” The Red List de fines the severity and specific causes of a species’ threat of extinction. The Red List has seven levels of conservation: least concern , near threatened , vulnerable, endangered, critically endangered , extinct in the wild , and extinct. Each category represents a different threat level. Species that are not threatened by extinction are placed within the first two categories—least concern and near-threatened. Those that are most threatened are placed within the next three categories, known as the threatened categories —vulnerable, endangered, and critically endangered. Those species that are extinct in some form are placed within the last two categories—extinct in the wild and extinct. Classifying a species as endangered has to do with its range and habitat, as well as its actual population. For this reason, a species can be of least concern in one area and endangered in another. The gray whale ( Eschrichtius robustus ), for instance, has a healthy population in the eastern Pacific Ocean, along the coast of North and South America. The population in the western Pacific, however, is critically endangered.

Least Concern Least concern is the lowest level of conservation . A species of least concern is one that has a widespread and abundant population. Human beings are a species of least concern, along with most domestic animals , such as dogs ( Canis familiaris ) and cats ( Felis catus ). Many wild animals, such as pigeons and houseflies ( Musca domestica ), are also classified as least concern. Near Threatened A near threatened species is one that is likely to qualify for a threatened category in the near future. Many species of violets , native to tropical jungles in South America and Africa, are near threatened, for instance. They have healthy populations, but their rainforest habitat is disappearing at a fast pace. People are cutting down huge areas of rainforest for development and timber . Many violet species are likely to become threatened. Vulnerable Species The definitions of the three threatened categories (vulnerable, endangered, and critically endangered) are based on five criteria: population reduction rate , geographic range, population size, population restrictions , and probability of extinction . Threatened categories have different thresholds for these criteria. As the population and range of the species decreases, the species becomes more threatened. 1) Population reduction rate A species is classified as vulnerable if its population has declined between 30 and 50 percent. This decline is measured over 10 years or three generations of the species, whichever is longer. A generation is the period of time between the birth of an animal and the time it is able to reproduce. Mice are able to reproduce when they are about one month old. Mouse populations are mostly tracked over 10-year periods. An elephant's generation lasts about 15 years. So, elephant populations are measured over 45-year periods. A species is vulnerable if its population has declined at least 50 percent and the cause of the decline is known. Habitat loss is the leading known cause of population decline. A species is also classified as vulnerable if its population has declined at least 30 percent and the cause of the decline is not known. A new, unknown virus , for example, could kill hundreds or even thousands of individuals before being identified. 2) Geographic range A species is vulnerable if its “ extent of occurrence ” is estimated to be less than 20,000 square kilometers (7,722 square miles). An extent of occurrence is the smallest area that could contain all sites of a species’ population. If all members of a species could survive in a single area, the size of that area is the species’ extent of occurrence. A species is also classified as vulnerable if its “ area of occupancy ” is estimated to be less than 2,000 square kilometers (772 square miles). An area of occupancy is where a specific population of that species resides. This area is often a breeding or nesting site in a species range. 3) Population size Species with fewer than 10,000 mature individuals are vulnerable. The species is also vulnerable if that population declines by at least 10 percent within 10 years or three generations, whichever is longer. 4) Population restrictions Population restriction is a combination of population and area of occupancy. A species is vulnerable if it is restricted to less than 1,000 mature individuals or an area of occupancy of less than 20 square kilometers (8 square miles). 5) Probability of extinction in the wild is at least 10 percent within 100 years. Biologists, anthropologists, meteorologists , and other scientists have developed complex ways to determine a species’ probability of extinction. These formulas calculate the chances a species can survive, without human protection, in the wild. Vulnerable Species: Ethiopian Banana Frog The Ethiopian banana frog ( Afrixalus enseticola ) is a small frog native to high- altitude areas of southern Ethiopia. It is a vulnerable species because its area of occupancy is less than 2,000 square kilometers (772 square miles). The extent and quality of its forest habitat are in decline. Threats to this habitat include forest clearance, mostly for housing and agriculture. Vulnerable Species: Snaggletooth Shark The snaggletooth shark ( Hemipristis elongatus ) is found in the tropical, coastal waters of the Indian and Pacific Oceans. Its area of occupancy is enormous, from Southeast Africa to the Philippines, and from China to Australia. However, the snaggletooth shark is a vulnerable species because of a severe population reduction rate. Its population has fallen more than 10 percent over 10 years. The number of these sharks is declining due to fisheries, especially in the Java Sea and Gulf of Thailand. The snaggletooth shark’s flesh, fins, and liver are considered high-quality foods. They are sold in commercial fish markets, as well as restaurants. Vulnerable Species: Galapagos Kelp Galapagos kelp ( Eisenia galapagensis ) is a type of seaweed only found near the Galapagos Islands in the Pacific Ocean. Galapagos kelp is classified as vulnerable because its population has declined more than 10 percent over 10 years. Climate change is the leading cause of decline among Galapagos kelp. El Niño, the natural weather pattern that brings unusually warm water to the Galapagos, is the leading agent of climate change in this area. Galapagos kelp is a cold-water species and does not adapt quickly to changes in water temperature.

Endangered Species 1) Population reduction rate A species is classified as endangered when its population has declined between 50 and 70 percent. This decline is measured over 10 years or three generations of the species, whichever is longer. A species is classified as endangered when its population has declined at least 70 percent and the cause of the decline is known. A species is also classified as endangered when its population has declined at least 50 percent and the cause of the decline is not known. 2) Geographic range An endangered species’ extent of occurrence is less than 5,000 square kilometers (1,930 square miles). An endangered species’ area of occupancy is less than 500 square kilometers (193 square miles). 3) Population size A species is classified as endangered when there are fewer than 2,500 mature individuals. When a species population declines by at least 20 percent within five years or two generations, it is also classified as endangered. 4) Population restrictions A species is classified as endangered when its population is restricted to less than 250 mature individuals. When a species’ population is this low, its area of occupancy is not considered. 5) Probability of extinction in the wild is at least 20 percent within 20 years or five generations, whichever is longer.

Endangered Species: Scimitar -horned Oryx The scimitar-horned oryx ( Oryx dammah ) is a species of antelope with long horns. Its range extends across northern Africa. Previously, the scimitar-horned oryx was listed as extinct in the wild because the last confirmed sighting of one was in 1988. However, the first group of scimitar-horned oryx was released back into the wild in Chad, in August 2016, and the population is growing. Overhunting and habitat loss, including competition with domestic livestock , are the main reasons for the decline of the oryx’s wild population. Captive herds are now kept in protected areas of Tunisia, Senegal, and Morocco. Scimitar-horned oryxes are also found in many zoos . Critically Endangered Species 1) Population reduction rate A critically endangered species’ population has declined between 80 and 90 percent. This decline is measured over 10 years or three generations of the species, whichever is longer. A species is classified as critically endangered when its population has declined at least 90 percent and the cause of the decline is known. A species is also classified as endangered when its population has declined at least 80 percent and the cause of the decline is not known. 2) Geographic range A critically endangered species’ extent of occurrence is less than 100 square kilometers (39 square miles). A critically endangered species’ area of occupancy is estimated to be less than 10 square kilometers (4 square miles). 3) Population size A species is classified as critically endangered when there are fewer than 250 mature individuals. A species is also classified as critically endangered when the number of mature individuals declines by at least 25 percent within three years or one generation, whichever is longer. 4) Population restrictions A species is classified as critically endangered when its population is restricted to less than 50 mature individuals. When a species’ population is this low, its area of occupancy is not considered. 5) Probability of extinction in the wild is at least 50 percent within 10 years or three generations, whichever is longer. Critically Endangered Species: Bolivian Chinchilla Rat The Bolivian chinchilla rat ( Abrocoma boliviensis ) is a rodent found in a small section of the Santa Cruz region of Bolivia. It is critically endangered because its extent of occurrence is less than 100 square kilometers (39 square miles). The major threat to this species is loss of its cloud forest habitat. People are clearing forests to create cattle pastures .

Critically Endangered Species: Transcaucasian Racerunner The Transcaucasian racerunner ( Eremias pleskei ) is a lizard found on the Armenian Plateau , located in Armenia, Azerbaijan, Iran, and Turkey. The Transcaucasian racerunner is a critically endangered species because of a huge population decline, estimated at more than 80 percent during the past 10 years. Threats to this species include the salination , or increased saltiness, of soil . Fertilizers used for agricultural development seep into the soil, increasing its saltiness. Racerunners live in and among the rocks and soil, and cannot adapt to the increased salt in their food and shelter. The racerunner is also losing habitat as people create trash dumps on their area of occupancy. Critically Endangered Species: White Ferula Mushroom The white ferula mushroom ( Pleurotus nebrodensis ) is a critically endangered species of fungus. The mushroom is critically endangered because its extent of occurrence is less than 100 square kilometers (39 square miles). It is only found in the northern part of the Italian island of Sicily, in the Mediterranean Sea. The leading threats to white ferula mushrooms are loss of habitat and overharvesting. White ferula mushrooms are a gourmet food item. Farmers and amateur mushroom hunters harvest the fungus for food and profit. The mushrooms can be sold for up to $100 per kilogram (2.2 pounds). Extinct in the Wild A species is extinct in the wild when it only survives in cultivation (plants), in captivity (animals), or as a population well outside its established range. A species may be listed as extinct in the wild only after years of surveys have failed to record an individual in its native or expected habitat.

Extinct in the Wild: Monut Kaala Cyanea The Mount Kaala cyanea ( Cyanea superba ) is a large, flowering tree native to the island of Oahu, in the U.S. state of Hawai‘i. The Mount Kaala cyanea has large, broad leaves and fleshy fruit. The tree is extinct in the wild largely because of invasive species. Non-native plants crowded the cyanea out of its habitat, and non-native animals such as pigs, rats, and slugs ate its fruit more quickly than it could reproduce. Mount Kaala cyanea trees survive in tropical nurseries and botanical gardens . Many botanists and conservationists look forward to establishing a new population in the wild. Extinct A species is extinct when there is no reasonable doubt that the last remaining individual of that species has died. Extinct: Cuban Macaw The Cuban macaw ( Ara tricolor ) was a tropical parrot native to Cuba and a small Cuban island, Isla de la Juventud. Hunting and collecting the birds for pets led to the bird’s extinction. The last specimen of the Cuban macaw was collected in 1864. Extinct: Ridley’s Stick Insect Ridley’s stick insect ( Pseudobactricia ridleyi ) was native to the tropical jungle of the island of Singapore. This insect, whose long, segmented body resembled a tree limb, is only known through a single specimen, collected more than 100 years ago. During the 20th century, Singapore experienced rapid development. Almost the entire jungle was cleared, depriving the insect of its habitat.

Endangered Species and People When a species is classified as endangered, governments and international organizations can work to protect it. Laws may limit hunting and destruction of the species’ habitat. Individuals and organizations that break these laws may face huge fines. Because of such actions, many species have recovered from their endangered status. The brown pelican ( Pelecanus occidentalis ) was taken off the endangered species list in 2009, for instance. This seabird is native to the coasts of North America and South America, as well as the islands of the Caribbean Sea. It is the state bird of the U.S. state of Louisiana. In 1970, the number of brown pelicans in the wild was estimated at 10,000. The bird was classified as vulnerable. During the 1970s and 1980s, governments and conservation groups worked to help the brown pelican recover. Young chicks were reared in hatching sites, then released into the wild. Human access to nesting sites was severely restricted. The pesticide DDT , which damaged the eggs of the brown pelican, was banned. During the 1980s, the number of brown pelicans soared. In 1988, the IUCN “delisted” the brown pelican. The bird, whose population is now in the hundreds of thousands, is now in the category of least concern.

Convention on Biological Diversity The Convention on Biological Diversity is an international treaty to sustain and protect the diversity of life on Earth. This includes conservation, sustainability, and sharing the benefits of genetic research and resources. The Convention on Biological Diversity has adopted the IUCN Red List of endangered species in order to monitor and research species' population and habitats. Three nations have not ratified the Convention on Biological Diversity: Andorra, the Holy See (Vatican), and the United States.

Lonesome George Lonesome George was the only living member of the Pinta Island tortoise ( Chelonoidis abingdoni ) known to exist. The Pinta Island tortoise was only found on Pinta, one of the Galapagos Islands. The Charles Darwin Research Station, a scientific facility in the Galapagos, offered a $10,000 reward to any zoo or individual for locating a single Pinta Island tortoise female. On June 25, 2012, Lonesome George died, leaving one more extinct species in the world.

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What is The IUCN Red List?

Established in 1964, The International Union for Conservation of Nature’s Red List of Threatened Species has evolved to become the world’s most comprehensive information source on the global conservation status of animal, fungi and plant species.

The IUCN Red List is a critical indicator of the health of the world’s biodiversity. Far more than a list of species and their status, it is a powerful tool to inform and catalyze action for biodiversity conservation and policy change, critical to protecting the natural resources we need to survive. It provides information about range, population size, habitat and ecology, use and/or trade, threats, and conservation actions that will help inform necessary conservation decisions.

The IUCN Red List Categories and Criteria

The IUCN Red List Categories and Criteria are intended to be an easily and widely understood system for classifying species at high risk of global extinction. It divides species into nine categories: Not Evaluated , Data Deficient , Least Concern , Near Threatened , Vulnerable , Endangered , Critically Endangered , Extinct in the Wild and Extinct .

Data Deficient (DD)

A taxon is Data Deficient (DD) when there is inadequate information to make a direct, or indirect, assessment of its risk of extinction based on its distribution and/or population status. A taxon in this category may be well studied, and its biology well known, but appropriate data on abundance and/or distribution are lacking.

Species categorized as Data Deficient (DD)

Least Concern (LC)

A taxon is Least Concern (LC) when it has been evaluated against the Red List criteria and does not qualify for Critically Endangered , Endangered , Vulnerable or Near Threatened .

Near Threatened (NT)

A taxon is Near Threatened (NT) when it has been evaluated against the criteria but does not qualify for Critically Endangered , Endangered or Vulnerable now, but is close to qualifying for or is likely to qualify for a threatened category in the near future.

Species categorized as Near Threatened (NT)

Vulnerable (VU)

A taxon is Vulnerable (VU) when the best available evidence indicates that it meets any of the criteria A to E for Vulnerable, and it is therefore considered to be facing a high risk of extinction in the wild.

Species categorized as Vulnerable (VU)

Endangered (EN)

A taxon is Endangered (EN) when the best available evidence indicates that it meets any of the criteria A to E for Endangered, and it is therefore considered to be facing a very high risk of extinction in the wild.

Species categorized as Endangered (EN)

Critically Endangered (CR)

A taxon is Critically Endangered (CR) when the best available evidence indicates that it meets any of the criteria A to E for Critically Endangered, and it is therefore considered to be facing an extremely high risk of extinction in the wild.

Species categorized as Critically Endangered (CR)

Extinct In The Wild (EW)

A taxon is Extinct In The Wild (EW) when it is known only to survive in cultivation, in captivity or as a naturalized population (or populations) well outside the past range. A taxon is presumed Extinct in the Wild when exhaustive surveys in known and/or expected habitat, at appropriate times (diurnal, seasonal, annual), throughout its historic range have failed to record an individual. Surveys should be over a time frame appropriate to the taxon's life cycle and life form.

Species categorized as Extinct In The Wild (EW)

Extinct (EX)

A taxon is Extinct (EX) when there is no reasonable doubt that the last individual has died. A taxon is presumed Extinct when exhaustive surveys in known and/or expected habitat, at appropriate times (diurnal, seasonal, annual), throughout its historic range have failed to record an individual. Surveys should be over a time frame appropriate to the taxon's life cycle and life form.

Species categorized as Extinct (EX)

Not Evaluated (NE)

A taxon is Not Evaluated (NE) when it has not yet been evaluated against the criteria.

Not Evaluated (NE) species are not published on the IUCN Red List

To date, more than 157,100 species have been assessed for The IUCN Red List.

This is an incredible achievement. However, our work is nowhere near complete. We need to substantially increase the number of wild species assessed, particularly plants, invertebrates and fungi.

Our current goal is to have 160,000 species assessed. Meeting this goal will provide the most up-to-date indication of the health of the world’s biodiversity to guide critical conservation action. This is only achievable with support from people like you.

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Extinction and the U.S. Endangered Species Act

Noah greenwald.

1 Center for Biological Diversity, Portland, OR, USA

Kieran F. Suckling

2 Center for Biological Diversity, Tucson, AZ, USA

Brett Hartl

3 Center for Biological Diversity, Washington, DC, USA

Loyal A. Mehrhoff

4 Center for Biological Diversity, Honolulu, HI, USA

Associated Data

The following information was supplied regarding data availability:

The raw data are available in a Supplementary File and include a complete list of the species we identified as extinct or possibly extinct along with all supporting information.

The U.S. Endangered Species Act is one of the strongest laws of any nation for preventing species extinction, but quantifying the Act’s effectiveness has proven difficult. To provide one measure of effectiveness, we identified listed species that have gone extinct and used previously developed methods to update an estimate of the number of species extinctions prevented by the Act. To date, only four species have been confirmed extinct with another 22 possibly extinct following protection. Another 71 listed species are extinct or possibly extinct, but were last seen before protections were enacted, meaning the Act’s protections never had the opportunity to save these species. In contrast, a total of 39 species have been fully recovered, including 23 in the last 10 years. We estimate the Endangered Species Act has prevented the extinction of roughly 291 species since passage in 1973, and has to date saved more than 99% of species under its protection.

Introduction

Passed in 1973, the U.S. Endangered Species Act (ESA) includes strong protections for listed threatened and endangered species and has helped stabilize and recover hundreds of listed species, such as the bald eagle and gray whale ( Taylor, Suckling & Rachlinski, 2005 ; Schwartz, 2008 ; Suckling et al., 2016 ). In part because of its strong protections, the ESA has engendered substantial opposition from industry lobby groups, who perceive the law as threatening their profits and have been effective in generating opposition to species protections among members of the U.S. Congress. One common refrain from opponents of the ESA in Congress and elsewhere is that the law is a failure because only 2% of listed species have been fully recovered and delisted ( Bishop, 2013 ).

The number of delistings, however, is a poor measure of the success of the ESA because most species have not been protected for sufficient time such that they would be expected to have recovered. Suckling et al. (2016) , for example, found that on average listed birds had been protected just 36 years, but their federal recovery plans estimated an average of 63 years for recovery. Short of recovery, a number of studies have found the ESA is effectively stabilizing or improving the status of species, using both biennial status assessments produced by the U.S. Fish and Wildlife Service for Congress and abundance trends ( Male & Bean, 2005 ; Taylor, Suckling & Rachlinski, 2005 ; Gibbs & Currie, 2012 ; Suckling et al., 2016 ).

In addition to recovering species, one of the primary purposes of the ESA is to prevent species extinction. Previous studies indicate the ESA has been successful in this regard ( McMillan & Wilcove, 1994 ; Scott et al., 2006 ). As of 2008, the ESA was estimated to have prevented the extinction of at least 227 species and the number of species delisted due to recovery outnumbered the number of species delisted for extinction by 14–7 ( Scott et al., 2006 ). In this study, we identified all ESA listed species that are extinct or possibly extinct to quantify the number of species for which ESA protections have failed and use these figures to update the estimated number of species extinctions prevented. This is the first study in over 20 years to compile data on extinction of ESA listed species, providing an important measure of one of the world’s strongest conservation laws ( McMillan & Wilcove, 1994 ).

To identify extinct or possibly extinct ESA listed species, we examined the status of all 1,747 (species, subspecies and distinct population segments) U.S. listed or formerly listed species, excluding species delisted based on a change in taxonomy or new information showing the original listing to have been erroneous. We determined species to be extinct or possibly extinct based on not being observed for at least 10 years, the occurrence of adequate surveys of their habitat, and presence of threats, such as destruction of habitat of the last known location or presence of invasive species known to eliminate the species.

To differentiate extinct and possibly extinct species we relied on determinations by the U.S. Fish and Wildlife Service, IUCN, species experts and other sources. In most cases, these determinations were qualitative rather quantitative. Species were considered extinct if surveys since the last observation were considered sufficient to conclude the species is highly likely to no longer exist, and possibly extinct if surveys were conducted after the last observation, but were not considered sufficient to conclude that extinction is highly likely ( Butchart, Stattersfield & Brooks, 2006 ; Scott et al., 2008 ).

Source information included 5-year reviews, listing rules and critical habitat designations by the U.S. Fish and Wildlife Service (for aquatic and terrestrial species) or NOAA Fisheries (for marine species), published and gray literature, personal communication with species experts and classifications and accounts by NatureServe, IUCN and the Hawaiian Plant Extinction Prevention program. For each species, we identified year of listing, year last seen, NatureServe and IUCN ranking, taxonomic group, and U.S. Fish and Wildlife Service region. For species last seen after listing, we also searched for abundance estimates at time of listing in order to give a sense of likelihood of survival regardless of ESA protection.

Following previously developed methods, we estimated the number of species extinctions prevented by the ESA by assuming that listed threatened and endangered species have a comparable extinction risk to IUCN endangered species, which was estimated as an average of 67% over 100 years ( Mace, 1995 ; Schwartz, 1999 ; Scott et al., 2006 ). We believe this estimate of extinction risk is conservative based on similarity of IUCN criteria to factors considered in ESA listings, observed low numbers for species at time of ESA listing and observed correspondence between ESA listed species and species classified as endangered or critically endangered by the IUCN ( Wilcove, McMillan & Winston, 1993 ; Wilcove & Master, 2005 ; Harris et al., 2012 ). Presumed extinction risk was then multiplied by the number of extant listed species and the proportion of a century in which species were protected by the ESA. Previous studies used the length of time the ESA has been in existence (1973-present) for the proportion of a century species have been protected ( Schwartz, 1999 ; Scott et al., 2006 ), but because many species have not been protected the entire 45 years the law has existed, we instead used the more conservative average length species were protected (25 years). This corresponds to the following formula:

We identified a total of 97 ESA listed species that are extinct (23) or possibly extinct (74). Of these, we found 71 extinct (19) or possibly extinct (52) species were last observed before they were listed under the ESA and thus are not relevant to determining the Act’s success in preventing extinction ( Table S1 ). These species were last seen an average of 24 years before protection was granted with a range of one to more than 80 years prior.

A total of 26 species were last seen after listing, of which four are confirmed extinct and 22 are possibly extinct ( Table S2 ). On average, these species were last seen 13 years after listing with a range of 2–23 years. We were able to find an abundance estimate at the time of listing for 19 of these species, ranging from one individual to more than 2,000 with an average of 272. In several cases, these estimates were based on extrapolations from very few sightings.

The distribution of extinct and possibly extinct species was non-random with 64 of the 97 species from Hawaii and other Pacific Islands, followed by 18 from the southeast ( Fig. 1 ). This was also the case for taxonomy. A total of 40 of the 97 species were mollusks dominated by Hawaiian tree snails and southeast mussels, followed by birds (18) and plants (17) ( Fig. 2 ).

Extinct or possibly extinct listed species by taxonomic group.

Extinct or possibly extinct listed species by U.S. Fish and Wildlife Service Region.

We identified several other species that have been missing for more than 10 years, but for which there has not been any effective surveys and thus classifying them as possibly extinct did not seem appropriate, including two Hawaiian yellow-faced bees ( Hylaeus facilis and Hylaeus hilaris ) (K. Magnacca, 2018, personal communication) and Fosberg’s love grass ( Eragrostis fosbergii ) ( U.S. Fish and Wildlife Service, 2011 ). If indeed extinct, all three were lost prior to protection under the ESA.

Including updated figures for number of listed species, time of protection and species extinctions, we estimate the ESA has prevented the extinction of roughly 291 species in its 45 year history. Based on the number of confirmed extinctions following listing, we further estimate that the ESA has to date prevented the extinction of more than 99% of species under its protection. To date, a total of 39 species have been delisted for recovery compared to four species that are extinct and 22 that are potentially extinct.

The few number of listed species that have gone extinct following protection combined with an estimated 291 species for which extinction was prevented demonstrate the ESA has achieved one of its core purposes—halting the loss of species. We will not attempt to catalog them here, but numerous individual examples provide further support for this conclusion. Well known species like the California condor ( Gymnogyps californianus ), black-footed ferret ( Mustela nigripes ) and Hawaiian monk seal ( Neomonachus schauinslandi ), as well as lesser known species like the yellowfin madtom ( Noturus flavipinnis ), are but a few of the species that likely would have been lost were it not for the ESA.

The madtom is a case in point. Wrongly presumed extinct when described in 1969, individual madtom were found in the Powell River in Tennessee and Copper Creek in Virginia and the species was protected under the ESA in 1977 ( U.S. Fish and Wildlife Service, 1977 ). Following protection, federal and state officials worked with a non-governmental organization, Conservation Fisheries Inc., to discover additional populations and repatriate the species to rivers and streams in its historic range and there are now populations of the yellowfin madtom in three different watersheds ( U.S. Fish and Wildlife Service, 2012a ). The history of the ESA is replete with similar such stories.

The distribution of extinct or possibly extinct listed species largely tracks those regions with the highest rates of species endangerment, including Hawaii and the Northern Mariana Islands with 64 of the 97 extinctions or possible extinctions, and the Southeast with 18 of the extinctions or possible extinctions, mostly freshwater species. The fragility of Hawaii’s endemic fauna to introduced species and habitat destruction and high degree of species imperilment is well recognized ( Duffy & Kraus, 2006 ). Similarly, the extinction and endangerment of freshwater fauna in the southeast is well documented ( Benz & Collins, 1997 ). To avoid further extinctions, these areas should be priorities for increased funding and effort.

Protection under the ESA came too late for the 71 species last seen prior to listing. It’s possible that some of these species survived undetected following listing, but we find this unlikely for most if not all of the species. It is very difficult to document extinction, but all of the species were the subject of survey both before and after listing, which is described in the listing rules and subsequent status surveys. In addition, the 71 species were last seen an average of 24 years prior to listing, providing a long window for detection prior to listing. If some of these species did survive after listing it was likely at very low numbers, such that recovery would have been difficult at best.

That these 71 species were lost before protections were applied clearly highlights the need to move quickly to protect species. Indeed, Suckling, Slack & Nowicki (2004) identified 42 species that went extinct while under consideration for protection. Since that analysis was completed, the U.S. Fish and Wildlife Service has determined five additional species did not qualify for protection because they were extinct, including the Tacoma pocket gopher ( Thomomys mazama tacomensis ), Tatum Cave beetle ( Pseudanophthalmus parvus ), Stephan’s riffle beetle ( Heterelmis stephani), beaverpond marstonia ( Marstonia castor ) and Ozark pyrg ( Marstonia ozarkensis ), meaning there are now 47 species that have gone extinct waiting for protection ( U.S. Fish and Wildlife Service, 2012b , 2016 , 2017 , 2018a ).

The U.S. Fish and Wildlife Service currently faces a backlog of more than 500 species that have been determined to potentially warrant protection, but which await a decision ( U.S. Fish and Wildlife Service, 2018b ). Under the ESA, decisions about protection for species are supposed to take 2 years, but on average it has taken the Fish and Wildlife Service 12 years ( Puckett, Kesler & Greenwald, 2016 ). Such lengthy wait times are certain to result in loss of further species and run counter to the purpose of the statute. This problem can be addressed by streamlining the Service’s process for listing species, which has become increasingly cumbersome, and by increasing funding for the listing program. For every species listed, the Service’s process includes review by upward of 20 people, including numerous individuals who have no specific knowledge of the species and in a number of cases are political appointees. We instead recommend that the Service adopt a process similar to scientific peer review, involving review by two to three qualified individuals.

The loss of 26 species after they were protected is indicative of conservation failure. This failure, however, in most cases cannot be wholly attributed to the ESA because most of these species were reduced to very low numbers by the time they were protected, making recovery difficult to impossible. Of the 19 species we could find an abundance estimate for at the time of listing, 13 had an estimated population fewer than 100 with eight having fewer than 10 individuals. Of the six other species, two Hawaiian birds, Oahu creeper ( Paroreomyza maculate ) and ‘O’u ( Psittirostra psittacea ) had estimated populations in the hundreds, but this was based on sightings of single individuals. Given the lack of further sightings and the presence of disease carrying mosquitoes throughout their habitat, these estimates were likely optimistic. The other four species, the dusky seaside sparrow ( Ammodramus maritimus nigrescens ), Morro Bay kangaroo rat ( Dipodomys heermanni morroensis ), pamakani ( Tetramolopium capillare ) and Curtis’ pearlymussel ( Epioblasma florentina curtisii ), had populations at the time of listing ranging from 100 to 3,000 individuals, but sufficient action was not taken to save them, making them true conservation failures.

At some level, all of the 97 ESA listed species that we identified as possibly extinct or extinct are conservation failures. For 42 of these species, the law itself was too late because they were last seen before the ESA was passed in 1973. But for others, there may have been time and we did not act quickly enough or dedicate sufficient resources to saving them. There are many examples of species both in the U.S. and internationally that have been successfully recovered even after dropping to very small numbers, but this can only occur with fast, effective action, resources and in many cases luck. The Mauritius kestrel ( Falco punctatus) , for example, was brought back from just two pairs ( Cade & Jones, 1993 ) and the Hawaiian plant extinction prevention program, which focuses on saving plants with fewer than 50 individuals, has rediscovered many species believed extinct, brought 177 species into cultivation, constructed fences to protect species from non-native predators and reintroduced many species into the wild ( Wood, 2012 , http://www.pepphi.org/ ).

The failure to provide sufficient resources for conservation of listed species, however, continues to the present. As many as 27 species of Oahu tree snail ( achatinella spp. ) are extinct or possibly extinct, yet expenditures for the species that still survive are inadequate to support minimal survey and captive propagation efforts. Likewise, the Hawaiian plant extinction prevention program, which has been so effective in saving species on the brink of extinction, is facing a budget cut of roughly 70% in 2019 ( http://www.pepphi.org/ ), which very likely could mean the extinction of dozens of plants that otherwise could be saved. Overall, Greenwald et al. (2016) estimate current recovery funding is roughly 3% of estimated recovery costs from federal recovery plans. We can save species from extinction, but it must be more of a priority for federal spending. Nevertheless, despite funding shortfalls and the tragedy of these species having gone extinct, the ESA has succeeded in preventing the extinction of the vast majority of listed species and in this regard is a success.

Management implications

Of the 97 species we identified as extinct or potentially extinct, only 11 have been delisted for extinction. Another 11 have been recommended for delisting due to extinction. The San Marcos gambusia ( Gambusia georgei ) could also be delisted since there is very little hope it survives. For the other 74 possibly extinct species, we recommend retaining protections in the hope that some will be rediscovered and because there is little cost in retaining listing.

Supplemental Information

Supplemental information 1.

Extinct or possibly extinct species broken out by whether last seen before or after protection was enacted, including relevant source data and literature cited.

Funding Statement

The authors received no funding for this work.

Additional Information and Declarations

All authors are employed by the Center for Biological Diversity which works to protect endangered species and their habitats.

Noah Greenwald conceived and designed the experiments, performed the experiments, analyzed the data, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft.

Kieran F. Suckling conceived and designed the experiments, performed the experiments, analyzed the data, authored or reviewed drafts of the paper, approved the final draft.

Brett Hartl conceived and designed the experiments, performed the experiments, analyzed the data, authored or reviewed drafts of the paper, approved the final draft.

Loyal A. Mehrhoff conceived and designed the experiments, performed the experiments, analyzed the data, authored or reviewed drafts of the paper, approved the final draft.

November 1, 2023

20 min read

Can We Save Every Species from Extinction?

The Endangered Species Act requires that every U.S. plant and animal be saved from extinction, but after 50 years, we have to do much more to prevent a biodiversity crisis

By Robert Kunzig

Snail Darter Percina tanasi. Listed as Endangered: 1975. Status: Delisted in 2022.

© Joel Sartore/National Geographic Photo Ark

A Bald Eagle disappeared into the trees on the far bank of the Tennessee River just as the two researchers at the bow of our modest motorboat began hauling in the trawl net. Eagles have rebounded so well that it's unusual not to see one here these days, Warren Stiles of the U.S. Fish and Wildlife Service told me as the net got closer. On an almost cloudless spring morning in the 50th year of the Endangered Species Act, only a third of a mile downstream from the Tennessee Valley Authority's big Nickajack Dam, we were searching for one of the ESA's more notorious beneficiaries: the Snail Darter. A few months earlier Stiles and the FWS had decided that, like the Bald Eagle, the little fish no longer belonged on the ESA's endangered species list. We were hoping to catch the first nonendangered specimen.

Dave Matthews, a TVA biologist, helped Stiles empty the trawl. Bits of wood and rock spilled onto the deck, along with a Common Logperch maybe six inches long. So did an even smaller fish; a hair over two inches, it had alternating vertical bands of dark and light brown, each flecked with the other color, a pattern that would have made it hard to see against the gravelly river bottom. It was a Snail Darter in its second year, Matthews said, not yet full-grown.

Everybody loves a Bald Eagle. There is much less consensus about the Snail Darter. Yet it epitomizes the main controversy still swirling around the ESA, signed into law on December 28, 1973, by President Richard Nixon: Can we save all the obscure species of this world, and should we even try, if they get in the way of human imperatives? The TVA didn't think so in the 1970s, when the plight of the Snail Darter—an early entry on the endangered species list—temporarily stopped the agency from completing a huge dam. When the U.S. attorney general argued the TVA's case before the Supreme Court with the aim of sidestepping the law, he waved a jar that held a dead, preserved Snail Darter in front of the nine judges in black robes, seeking to convey its insignificance.

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Now I was looking at a living specimen. It darted around the bottom of a white bucket, bonking its nose against the side and delicately fluttering the translucent fins that swept back toward its tail.

“It's kind of cute,” I said.

Matthews laughed and slapped me on the shoulder. “I like this guy!” he said. “Most people are like, ‘Really? That's it?’ ” He took a picture of the fish and clipped a sliver off its tail fin for DNA analysis but left it otherwise unharmed. Then he had me pour it back into the river. The next trawl, a few miles downstream, brought up seven more specimens.

In the late 1970s the Snail Darter seemed confined to a single stretch of a single tributary of the Tennessee River, the Little Tennessee, and to be doomed by the TVA's ill-considered Tellico Dam, which was being built on the tributary. The first step on its twisting path to recovery came in 1978, when the U.S. Supreme Court ruled, surprisingly, that the ESA gave the darter priority even over an almost finished dam. “It was when the government stood up and said, ‘Every species matters, and we meant it when we said we're going to protect every species under the Endangered Species Act,’” says Tierra Curry, a senior scientist at the Center for Biological Diversity.

Bald Eagle Haliaeetus leucocephalus. Listed as Endangered: 1967. Status: Delisted in 2007. Credit: © Joel Sartore/National Geographic Photo Ark

Today the Snail Darter can be found along 400 miles of the river's main stem and multiple tributaries. ESA enforcement has saved dozens of other species from extinction. Bald Eagles, American Alligators and Peregrine Falcons are just a few of the roughly 60 species that had recovered enough to be “delisted” by late 2023.

And yet the U.S., like the planet as a whole, faces a growing biodiversity crisis. Less than 6 percent of the animals and plants ever placed on the list have been delisted; many of the rest have made scant progress toward recovery. What's more, the list is far from complete: roughly a third of all vertebrates and vascular plants in the U.S. are vulnerable to extinction, says Bruce Stein, chief scientist at the National Wildlife Federation. Populations are falling even for species that aren't yet in danger. “There are a third fewer birds flying around now than in the 1970s,” Stein says. We're much less likely to see a White-throated Sparrow or a Red-winged Blackbird, for example, even though neither species is yet endangered.

The U.S. is far emptier of wildlife sights and sounds than it was 50 years ago, primarily because habitat—forests, grasslands, rivers—has been relentlessly appropriated for human purposes. The ESA was never designed to stop that trend, any more than it is equipped to deal with the next massive threat to wildlife: climate change. Nevertheless, its many proponents say, it is a powerful, foresightful law that we could implement more wisely and effectively, perhaps especially to foster stewardship among private landowners. And modest new measures, such as the Recovering America's Wildlife Act—a bill with bipartisan support—could further protect flora and fauna.

That is, if special interests don't flout the law. After the 1978 Supreme Court decision, Congress passed a special exemption to the ESA allowing the TVA to complete the Tellico Dam. The Snail Darter managed to survive because the TVA transplanted some of the fish from the Little Tennessee, because remnant populations turned up elsewhere in the Tennessee Valley, and because local rivers and streams slowly became less polluted following the 1972 Clean Water Act, which helped fish rebound.

Under pressure from people enforcing the ESA, the TVA also changed the way it managed its dams throughout the valley. It started aerating the depths of its reservoirs, in some places by injecting oxygen. It began releasing water from the dams more regularly to maintain a minimum flow that sweeps silt off the river bottom, exposing the clean gravel that Snail Darters need to lay their eggs and feed on snails. The river system “is acting more like a real river,” Matthews says. Basically, the TVA started considering the needs of wildlife, which is really what the ESA requires. “The Endangered Species Act works,” Matthews says. “With just a little bit of help, [wildlife] can recover.”

The trouble is that many animals and plants aren't getting that help—because government resources are too limited, because private landowners are alienated by the ESA instead of engaged with it, and because as a nation the U.S. has never fully committed to the ESA's essence. Instead, for half a century, the law has been one more thing that polarizes people's thinking.

I t may seem impossible today to imagine the political consensus that prevailed on environmental matters in 1973. The U.S. Senate approved the ESA unanimously, and the House passed it by a vote of 390 to 12. “Some people have referred to it as almost a statement of religion coming out of the Congress,” says Gary Frazer, who as assistant director for ecological services at the FWS has been overseeing the act's implementation for nearly 25 years.

Gopher Tortoise Gopherus polyphemus . Listed as Threatened: 1987. Status: Still threatened. Credit: ©Joel Sartore/National Geographic Photo Ark

But loss of faith began five years later with the Snail Darter case. Congresspeople who had been thinking of eagles, bears and Whooping Cranes when they passed the ESA, and had not fully appreciated the reach of the sweeping language they had approved, were disabused by the Supreme Court. It found that the legislation had created, “wisely or not ... an absolute duty to preserve all endangered species,” Chief Justice Warren E. Burger said after the Snail Darter case concluded. Even a recently discovered tiny fish had to be saved, “whatever the cost,” he wrote in the decision.

Was that wise? For both environmentalists such as Curry and many nonenvironmentalists, the answer has always been absolutely. The ESA “is the basic Bill of Rights for species other than ourselves,” says National Geographic photographer Joel Sartore, who is building a “photo ark” of every animal visible to the naked eye as a record against extinction. (He has taken studio portraits of 15,000 species so far.) But to critics, the Snail Darter decision always defied common sense. They thought it was “crazy,” says Michael Bean, a leading ESA expert, now retired from the Environmental Defense Fund. “That dichotomy of view has remained with us for the past 45 years.”

According to veteran Washington, D.C., environmental attorney Lowell E. Baier, author of a new history called The Codex of the Endangered Species Act, both the act itself and its early implementation reflected a top-down, federal “command-and-control mentality” that still breeds resentment. FWS field agents in the early days often saw themselves as combat biologists enforcing the act's prohibitions. After the Northern Spotted Owl's listing got tangled up in a bitter 1990s conflict over logging of old-growth forests in the Pacific Northwest, the FWS became more flexible in working out arrangements. “But the dark mythology of the first 20 years continues in the minds of much of America,” Baier says.

Credit: June Minju Kim ( map ); Source: David Matthews, Tennessee Valley Authority ( reference )

The law can impose real burdens on landowners. Before doing anything that might “harass” or “harm” an endangered species, including modifying its habitat, they need to get a permit from the FWS and present a “habitat conservation plan.” Prosecutions aren't common, because evidence can be elusive, but what Bean calls “the cloud of uncertainty” surrounding what landowners can and cannot do can be distressing.

Requirements the ESA places on federal agencies such as the Forest Service and the Bureau of Land Management—or on the TVA—can have large economic impacts. Section 7 of the act prohibits agencies from taking, permitting or funding any action that is likely to “jeopardize the continued existence” of a listed species. If jeopardy seems possible, the agency must consult with the FWS first (or the National Marine Fisheries Service for marine species) and seek alternative plans.

“When people talk about how the ESA stops projects, they've been talking about section 7,” says conservation biologist Jacob Malcom. The Northern Spotted Owl is a strong example: an economic analysis suggests the logging restrictions eliminated thousands of timber-industry jobs, fueling conservative arguments that the ESA harms humans and economic growth.

In recent decades, however, that view has been based “on anecdote, not evidence,” Malcom claims. At Defenders of Wildlife, where he worked until 2022 (he's now at the U.S. Department of the Interior), he and his colleagues analyzed 88,290 consultations between the FWS and other agencies from 2008 to 2015. “Zero projects were stopped,” Malcom says. His group also found that federal agencies were only rarely taking the active measures to recover a species that section 7 requires—like what the TVA did for the Snail Darter. For many listed species, the FWS does not even have recovery plans.

Endangered species also might not recover because “most species are not receiving protection until they have reached dangerously low population sizes,” according to a 2022 study by Erich K. Eberhard of Columbia University and his colleagues. Most listings occur only after the FWS has been petitioned or sued by an environmental group—often the Center for Biological Diversity, which claims credit for 742 listings. Years may go by between petition and listing, during which time the species' population dwindles. Noah Greenwald, the center's endangered species director, thinks the FWS avoids listings to avoid controversy—that it has internalized opposition to the ESA.

He and other experts also say that work regarding endangered species is drastically underfunded. As more species are listed, the funding per species declines. “Congress hasn't come to grips with the biodiversity crisis,” says Baier, who lobbies lawmakers regularly. “When you talk to them about biodiversity, their eyes glaze over.” Just this year federal lawmakers enacted a special provision exempting the Mountain Valley Pipeline from the ESA and other challenges, much as Congress had exempted the Tellico Dam. Environmentalists say the gas pipeline, running from West Virginia to Virginia, threatens the Candy Darter, a colorful small fish. The Inflation Reduction Act of 2022 provided a rare bit of good news: it granted the FWS $62.5 million to hire more biologists to prepare recovery plans.

The ESA is often likened to an emergency room for species: overcrowded and understaffed, it has somehow managed to keep patients alive, but it doesn't do much more. The law contains no mandate to restore ecosystems to health even though it recognizes such work as essential for thriving wildlife. “Its goal is to make things better, but its tools are designed to keep things from getting worse,” Bean says. Its ability to do even that will be severely tested in coming decades by threats it was never designed to confront.

T he ESA requires a species to be listed as “threatened” if it might be in danger of extinction in the “foreseeable future.” The foreseeable future will be warmer. Rising average temperatures are a problem, but higher heat extremes are a bigger threat, according to a 2020 study.

Scientists have named climate change as the main cause of only a few extinctions worldwide. But experts expect that number to surge. Climate change has been “a factor in almost every species we've listed in at least the past 15 years,” Frazer says. Yet scientists struggle to forecast whether individual species can “persist in place or shift in space”—as Stein and his co-authors put it in a recent paper—or will be unable to adapt at all and will go extinct. On June 30 the FWS issued a new rule that will make it easier to move species outside their historical range—a practice it once forbade except in extreme circumstances.

Credit: June Minju Kim ( graphic ); Brown Bird Design ( illustrations ); Sources: U.S. Fish & Wildlife Service Environmental Conservation Online System; U.S. Federal Endangered and Threatened Species by Calendar Year https://ecos.fws.gov/ecp/report/species-listings-by-year-totals ( annual data through 2022 ); Listed Species Summary (Boxscore) https://ecos.fws.gov/ecp/report/boxscore ( cumulative data up to September 18, 2023, and annual data for coral ); Delisted Species https://ecos.fws.gov/ecp/report/species-delisted ( delisted data through 2022 )

Eventually, though, “climate change is going to swamp the ESA,” says J. B. Ruhl, a law professor at Vanderbilt University, who has been writing about the problem for decades. “As more and more species are threatened, I don't know what the agency does with that.” To offer a practical answer, in a 2008 paper he urged the FWS to aggressively identify the species most at risk and not waste resources on ones that seem sure to expire.

Yet when I asked Frazer which urgent issues were commanding his attention right now, his first thought wasn't climate; it was renewable energy. “Renewable energy is going to leave a big footprint on the planet and on our country,” he says, some of it threatening plants and animals if not implemented well. “The Inflation Reduction Act is going to lead to an explosion of more wind and solar across the landscape.

Long before President Joe Biden signed that landmark law, conflicts were proliferating: Desert Tortoise versus solar farms in the Mojave Desert, Golden Eagles versus wind farms in Wyoming, Tiehm's Buckwheat (a little desert flower) versus lithium mining in Nevada. The mine case is a close parallel to that of Snail Darters versus the Tellico Dam. The flower, listed as endangered just last year, grows on only a few acres of mountainside in western Nevada, right where a mining company wants to extract lithium. The Center for Biological Diversity has led the fight to save it. Elsewhere in Nevada people have used the ESA to stop, for the moment, a proposed geothermal plant that might threaten the two-inch Dixie Valley Toad, discovered in 2017 and also declared endangered last year.

Does an absolute duty to preserve all endangered species make sense in such places? In a recent essay entitled “A Time for Triage,” Columbia law professor Michael Gerrard argues that “the environmental community has trade-off denial. We don't recognize that it's too late to preserve everything we consider precious.” In his view, given the urgency of building the infrastructure to fight climate change, we need to be willing to let a species go after we've done our best to save it. Environmental lawyers adept at challenging fossil-fuel projects, using the ESA and other statutes, should consider holding their fire against renewable installations. “Just because you have bullets doesn't mean you shoot them in every direction,” Gerrard says. “You pick your targets.” In the long run, he and others argue, climate change poses a bigger threat to wildlife than wind turbines and solar farms do.

For now habitat loss remains the overwhelming threat. What's truly needed to preserve the U.S.'s wondrous biodiversity, both Stein and Ruhl say, is a national network of conserved ecosystems. That won't be built with our present politics. But two more practical initiatives might help.

The first is the Recovering America's Wildlife Act, which narrowly missed passage in 2022 and has been reintroduced this year. It builds on the success of the 1937 Pittman-Robertson Act, which funds state wildlife agencies through a federal excise tax on guns and ammunition. That law was adopted to address a decline in game species that had hunters alarmed. The state refuges and other programs it funded are why deer, ducks and Wild Turkeys are no longer scarce.

The recovery act would provide $1.3 billion a year to states and nearly $100 million to Native American tribes to conserve nongame species. It has bipartisan support, in part, Stein says, because it would help arrest the decline of a species before the ESA's “regulatory hammer” falls. Although it would be a large boost to state wildlife budgets, the funding would be a rounding error in federal spending. But last year Congress couldn't agree on how to pay for the measure. Passage “would be a really big deal for nature,” Curry says.

Oyster Mussel. Epioblasma capsaeformis.  Listed as Endangered: 1997. Status: Still endangered. Credit: © Joel Sartore/National Geographic Photo Ark

The second initiative that could promote species conservation is already underway: bringing landowners into the fold. Most wildlife habitat east of the Rocky Mountains is on private land. That's also where habitat loss is happening fastest. Some experts say conservation isn't likely to succeed unless the FWS works more collaboratively with landowners, adding carrots to the ESA's regulatory stick. Bean has long promoted the idea, including when he worked at the Interior Department from 2009 to early 2017. The approach started, he says, with the Red-cockaded Woodpecker.

When the ESA was passed, there were fewer than 10,000 Red-cockaded Woodpeckers left of the millions that had once lived in the Southeast. Humans had cut down the old pine trees, chiefly Longleaf Pine, that the birds excavate cavities in for roosting and nesting. An appropriate tree has to be large, at least 60 to 80 years old, and there aren't many like that left. The longleaf forest, which once carpeted up to 90 million acres from Virginia to Texas, has been reduced to less than three million acres of fragments.

In the 1980s the ESA wasn't helping because it provided little incentive to preserve forest on private land. In fact, Bean says, it did the opposite: landowners would sometimes clear-cut potential woodpecker habitat just to avoid the law's constraints. The woodpecker population continued to drop until the 1990s. That's when Bean and his Environmental Defense Fund colleagues persuaded the FWS to adopt “safe-harbor agreements” as a simple solution. An agreement promised landowners that if they let pines grow older or took other woodpecker-friendly measures, they wouldn't be punished; they remained free to decide later to cut the forest back to the baseline condition it had been in when the agreement was signed.

That modest carrot was inducement enough to quiet the chainsaws in some places. “The downward trends have been reversed,” Bean says. “In places like South Carolina, where they have literally hundreds of thousands of acres of privately owned forest enrolled, Red-cockaded Woodpecker numbers have shot up dramatically.”

The woodpecker is still endangered. It still needs help. Because there aren't enough old pines, land managers are inserting lined, artificial cavities into younger trees and sometimes moving birds into them to expand the population. They are also using prescribed fires or power tools to keep the longleaf understory open and grassy, the way fires set by lightning or Indigenous people once kept it and the way the woodpeckers like it. Most of this work is taking place, and most Red-cockaded Woodpeckers are still living, on state or federal land such as military bases. But a lot more longleaf must be restored to get the birds delisted, which means collaborating with private landowners, who own 80 percent of the habitat.

Leo Miranda-Castro, who retired last December as director of the FWS's southeast region, says the collaborative approach took hold at regional headquarters in Atlanta in 2010. The Center for Biological Diversity had dropped a “mega petition” demanding that the FWS consider 404 new species for listing. The volume would have been “overwhelming,” Miranda-Castro says. “That's when we decided, ‘Hey, we cannot do this in the traditional way.’ The fear of listing so many species was a catalyst” to look for cases where conservation work might make a listing unnecessary.

An agreement affecting the Gopher Tortoise shows what is possible. Like the woodpeckers, it is adapted to open-canopied longleaf forests, where it basks in the sun, feeds on herbaceous plants and digs deep burrows in the sandy soil. The tortoise is a keystone species: more than 300 other animals, including snakes, foxes and skunks, shelter in its burrows. But its numbers have been declining for decades.

Urbanization is the main threat to the tortoises, but timberland can be managed in a way that leaves room for them. Eager to keep the species off the list, timber companies, which own 20 million acres in its range, agreed to figure out how to do that—above all by returning fire to the landscape and keeping the canopy open. One timber company, Resource Management Service, said it would restore Longleaf Pine on about 3,700 acres in the Florida panhandle, perhaps expanding to 200,000 acres eventually. It even offered to bring other endangered species onto its land, which delighted Miranda-Castro: “I had never heard about that happening before.” Last fall the FWS announced that the tortoise didn't need to be listed in most of its range.

Miranda-Castro now directs Conservation Without Conflict, an organization that seeks to foster conversation and negotiation in settings where the ESA has more often generated litigation. “For the first 50 years the stick has been used the most,” Miranda-Castro says. “For the next 50 years we're going to be using the carrots way more.” On his own farm outside Fort Moore, Ga., he grows Longleaf Pine—and Gopher Tortoises are benefiting.

Whooping Crane. Grus americana.  Listed as Endangered: 1967. Status: Still endangered. Credit: © Joel Sartore/National Geographic Photo Ark

The Center for Biological Diversity doubts that carrots alone will save the reptile. It points out that the FWS's own models show small subpopulations vanishing over the next few decades and the total population falling by nearly a third. In August 2023 it filed suit against the FWS, demanding the Gopher Tortoise be listed.

The FWS itself resorted to the stick this year when it listed the Lesser Prairie-Chicken, a bird whose grassland home in the Southern Plains has long been encroached on by agriculture and the energy industry. The Senate promptly voted to overturn that listing, but President Biden promised to veto that measure if it passes the House.

B ehind the debates over strategy lurks the vexing question: Can we save all species? The answer is no. Extinctions will keep happening. In 2021 the FWS proposed to delist 23 more species—not because they had recovered but because they hadn't been seen in decades and were presumed gone. There is a difference, though, between acknowledging the reality of extinction and deliberately deciding to let a species go. Some people are willing to do the latter; others are not. Bean thinks a person's view has a lot to do with how much they've been exposed to wildlife, especially as a child.

Zygmunt Plater, a professor emeritus at Boston College Law School, was the attorney in the 1978 Snail Darter case, fighting for hundreds of farmers whose land would be submerged by the Tellico Dam. At one point in the proceedings Justice Lewis F. Powell, Jr., asked him, “What purpose is served, if any, by these little darters? Are they used for food?” Plater thinks creatures such as the darter alert us to the threat our actions pose to them and to ourselves. They prompt us to consider alternatives.

The ESA aims to save species, but for that to happen, ecosystems have to be preserved. Protecting the Northern Spotted Owl has saved at least a small fraction of old-growth forest in the Pacific Northwest. Concern about the Red-cockaded Woodpecker and the Gopher Tortoise is aiding the preservation of longleaf forests in the Southeast. The Snail Darter wasn't enough to stop the Tellico Dam, which drowned historic Cherokee sites and 300 farms, mostly for real estate development. But after the controversy, the presence of a couple of endangered mussels did help dissuade the TVA from completing yet another dam, on the Duck River in central Tennessee. That river is now recognized as one of the most biodiverse in North America.

The ESA forced states to take stock of the wildlife they harbored, says Jim Williams, who as a young biologist with the FWS was responsible for listing both the Snail Darter and mussels in the Duck River. Williams grew up in Alabama, where I live. “We didn't know what the hell we had,” he says. “People started looking around and found all sorts of new species.” Many were mussels and little fish. In a 2002 survey, Stein found that Alabama ranked fifth among U.S. states in species diversity. It also ranks second-highest for extinctions; of the 23 extinct species the FWS recently proposed for delisting, eight were mussels, and seven of those were found in Alabama.

One morning this past spring, at a cabin on the banks of Shoal Creek in northern Alabama, I attended a kind of jamboree of local freshwater biologists. At the center of the action, in the shade of a second-floor deck, sat Sartore. He had come to board more species onto his photo ark, and the biologists—most of them from the TVA—were only too glad to help, fanning out to collect critters to be decanted into Sartore's narrow, flood-lit aquarium. He sat hunched before it, a black cloth draped over his head and camera, snapping away like a fashion photographer, occasionally directing whoever was available to prod whatever animal was in the tank into a more artful pose.

As I watched, he photographed a striated darter that didn't yet have a name, a Yellow Bass, an Orangefin Shiner and a giant crayfish discovered in 2011 in the very creek we were at. Sartore's goal is to help people who never meet such creatures feel the weight of extinction—and to have a worthy remembrance of the animals if they do vanish from Earth.

With TVA biologist Todd Amacker, I walked down to the creek and sat on the bank. Amacker is a mussel specialist, following in Williams's footsteps. As his colleagues waded in the shoals with nets, he gave me a quick primer on mussel reproduction. Their peculiar antics made me care even more about their survival.

There are hundreds of freshwater mussel species, Amacker explained, and almost every one tricks a particular species of fish into raising its larvae. The Wavy-rayed Lampmussel, for example, extrudes part of its flesh in the shape of a minnow to lure black bass—and then squirts larvae into the bass's open mouth so they can latch on to its gills and fatten on its blood. Another mussel dangles its larvae at the end of a yard-long fishing line of mucus. The Duck River Darter Snapper—a member of a genus that has already lost most of its species to extinction—lures and then clamps its shell shut on the head of a hapless fish, inoculating it with larvae. “You can't make this up,” Amacker said. Each relationship has evolved over the ages in a particular place.

The small band of biologists who are trying to cultivate the endangered mussels in labs must figure out which fish a particular mussel needs. It's the type of tedious trial-and-error work conservation biologists call “heroic,” the kind that helped to save California Condors and Whooping Cranes. Except these mussels are eyeless, brainless, little brown creatures that few people have ever heard of.

For most mussels, conditions are better now than half a century ago, Amacker said. But some are so rare it's hard to imagine they can be saved. I asked Amacker whether it was worth the effort or whether we just need to accept that we must let some species go. The catch in his voice almost made me regret the question.

“I'm not going to tell you it's not worth the effort,” he said. “It's more that there's no hope for them.” He paused, then collected himself. “Who are we to be the ones responsible for letting a species die?” he went on. “They've been around so long. That's not my answer as a biologist; that's my answer as a human. Who are we to make it happen?”

Robert Kunzig is a freelance writer in Birmingham, Ala., and a former senior editor at National Geographic, Discover and Scientific American .

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Saving Endangered Species: A Case Study Using Global Amphibian Declines

How are Endangered Species Identified?

The International Union for Conservation of Nature and Natural Resources (IUCN) Red List uses a hierarchical structure of nine categories for assigning threat levels for each species or subspecies. These categories range from 'Extinct' to 'Least Concern' (Figure 1). At the highest levels of threat, taxa are listed as 'Critically Endangered,' 'Endangered,' or 'Vulnerable,' all of which are given 'Threatened' status. A series of quantitative criteria is measured for inclusion in these categories, including: reduction in population size, geographic range size and occupancy of area, total population size, and probability of extinction. The evaluation of these criteria includes analyses regarding the number of mature individuals, generation time, and population fragmentation. Each taxon is appraised using all criteria. However, since not all criteria are appropriate for assessing all taxa, satisfying any one criterion qualifies listing at that designated threat level.

There are a variety of human activities that contribute to species becoming threatened, including habitat destruction, fragmentation, and degradation, pollution, introduction of non-native species, disease, climate change, and over-exploitation. In many cases, multiple causes act in concert to threaten populations. Though the causes underlying population declines are numerous, some traits serve as predictors of whether species are likely to be more vulnerable to the causes listed. For example, many species that have become endangered exhibit large body size, specialized diet and/or habitat requirements, small population size, low reproductive output, limited geographic distribution, and great economic value (McKinney 1997).

How to Save Endangered Species

There are a variety of methods currently being implemented to save endangered species. The most common are creation of protected areas, captive breeding and reintroduction, conservation legislation, and increased public awareness.

Protected areas

An effective and internationally recognized strategy for conserving species and ecosystems is to designate protected areas. The United Nations Environment Programme World Conservation Monitoring Center (UNEP-WCMC) defines a protected area as "an area of land and/or sea especially dedicated to the protection of biological diversity and of natural and associated cultural resources, managed through legal or other effective means." Worldwide, extensive systems of protected areas have been developed and include national parks, state/provincial parks, wildlife refuges, and nature reserves, all of which differ in their management objectives and degree of protection. The IUCN has defined six protected area management categories, based on primary management objective (Table 1). These categories are defined in detail in the Guidelines for Protected Areas Management Categories published by IUCN in 1994.

The World Database on Protected Areas (WDPA) records all nationally designated terrestrial and marine protected areas whose extent is known. These data are collected from national and regional governing bodies and non-governmental organizations. Currently, there are over 120,000 protected areas (2008 estimate, UNEP-WCMC), covering about 21 million square kilometers of land and sea. Since 1872, there has been a dramatic increase in the global number and extent of nationally designated protected areas (Figure 2). Well-planned and -managed protected areas not only benefit species at risk, but other species associated with them, thereby increasing the overall amount of biodiversity conserved. Despite increases in the size and number of protected areas, however, the overall area constitutes a small percentage of the earth's surface. Because these areas are critical to the conservation of biodiversity, the designation of more areas for protection and increases in the sizes of those areas already in existence are necessary.

Another opportunity for creating protected areas is the Alliance for Zero Extinction (AZE), an international consortium of conservation organizations that specifically targets protection of key sites that represent sanctuaries of one or more Endangered or Critically Endangered species. The AZE focuses on species whose habitats have been degraded or whose ranges are exceptionally small, making them susceptible to outside threats. Three criteria must be met in order to prioritize a site for protection (Table 2). To date, 588 sites encompassing 920 threatened species of mammals, birds, reptiles, amphibians, conifers and corals have been identified. The goal of such efforts is to prevent the most imminent species extinctions by increasing global awareness of these key areas.

Captive breeding and reintroduction

Some species in danger of extinction in the wild are brought into captivity to either safeguard against imminent extinction or to increase population numbers. The primary goals of captive breeding programs are to establish populations via controlled breeding that are: a) large enough to be demographically stable; and b) genetically healthy (Ebenhard 1995). These objectives ensure that populations will exhibit a healthy age structure, resistance to disease, consistent reproduction, and preservation of the gene pool to minimize and/or avoid problems associated with inbreeding. Successful captive breeding programs include those for the Guam rail, scimitar-horned oryx, and Przewalski's horse. (See iucnredlist.org for details.)

Establishing captive populations is an important contribution of zoos and aquariums to the conservation of endangered species. Zoos and aquariums have limited space, however, so to maintain healthy populations, they cooperate in managing their collections as breeding populations from international to regional levels. The World Association of Zoos and Aquariums (WAZA) is the organization that unites the world's zoos and aquariums in cooperative breeding programs. Perhaps the most important tools in managing these programs are studbooks, which ensure that captive populations maintain a sufficient size, demographic stability, and ample genetic diversity. All information pertinent to management of the species in question is included (e.g., animal registration number, birth date, parentage, behavioral traits that may affect breeding). These studbooks are used to make recommendations regarding which individuals should be bred, how often, and with whom in order to minimize inbreeding and, thus, enhance the demographic and genetic security of the captive population.

Another goal of some captive breeding programs is to reintroduce animals to the wild to reestablish populations. Examples of successful introductions using captive-bred stock include California condors (Ralls & Ballou 2004) and black-footed ferrets (Russell et al. 1994). Reintroductions can also utilize individuals from healthy wild populations, meaning individuals that are thriving in one part of the range are introduced to an area where the species was extirpated. Reintroduction programs involve the release of individuals back into portions of their historic range, where they are monitored and either roam freely (e.g., gray wolves released in Yellowstone National Park) or are contained within an enclosed area (e.g., elk in Land Between the Lakes National Recreation Area in western Kentucky; Figure 3). However, reintroduction is only feasible if survival can be assured. Biologists must ascertain whether: a) the original threats persist and/or can be mitigated; and b) sufficient habitat remains, or else survival will be low upon release.

Laws and regulations

Biodiversity is protected by laws at state/provincial, national, and international levels. Arguably the most influential law is the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) which is an agreement between governments (i.e., countries) that controls international trade in wild animals, plants, and their parts to ensure continued survival. International trade in wildlife is a multi-billion dollar industry that affects millions of plants and animals. As a result, CITES lists species in three Appendices according to the level of protection they require to avoid over-exploitation; species listed in Appendix I require the most protection and, thus, trade limitations (Table 3). Currently, approximately 30,000 species are protected under CITES (Table 4).

The trade in wildlife is an international issue and, as such, cooperation between countries is required to regulate trade under CITES. However, member countries adhere to regulations voluntarily and, consequently, they must implement them. Most important, CITES does not take the place of national laws; member countries must also have their own domestic legislation in place to execute the Convention.

Public awareness

In general, the public is unaware about the current extinction crisis. Public awareness can be increased through education and citizen science programs. Conservation education often begins in elementary school and may be enhanced through summer camps or family vacations that are nature oriented (e.g., involve visiting national or state parks). Early positive experiences with nature are essential for children to gain an appreciation for wildlife and the problems species face. In high school, this education is continued through formal science education and extra-curricular activities. Other means of increasing public awareness involve internet websites where subscribers can receive emails from conservation organizations like Defenders of Wildlife, Environmental Defense, and World Wildlife Fund. In many cases, these organizations provide updates on the status of endangered species and promote letter writing to elected officials in requesting protection for endangered species and their habitats.

CASE STUDY IN CONSERVATION: Global declines in amphibian populations

Amphibians are one of the earth's most imperiled vertebrate groups, with approximately one-third of all species facing extinction (Stuart et al . 2004). Causes of amphibian population declines and extinctions echo those listed in the introductory paragraphs but primarily consist of drainage and development of wetland habitats and surrounding uplands, contamination of aquatic habitats, predation by or hybridization with introduced species, climate change, and over-harvesting (Collins & Storfer 2003). In addition, the recent declines observed in relatively pristine areas, such as state, provincial, and national parks worldwide have brought to light the tremendous impact of pathogens on amphibian populations, most notably that of the amphibian-killing fungus Batrachochytrium dendrobatidis (Bd). So what is being done to preserve amphibian diversity?

To address the historic sources of amphibian population declines, such as overexploitation and habitat loss, national and international legislation exists to monitor the trade in amphibians and prevent further reductions in available habitat. Although international trade in amphibians is less common relative to trade in other vertebrate groups, CITES currently lists 131 species in Appendices I-III. Furthermore, IUCN currently lists 509, 767, and 657 amphibian species as Critically Endangered, Endangered, or Vulnerable (Figure 4), respectively. These species' native habitats are afforded protection at various levels of organization. The AZE has identified 588 sites worldwide exhibiting at least one criterion for protection (Table 2), and these sites are home to hundreds of amphibian species listed by IUCN as between Vulnerable and Critically Endangered. In addition, IUCN's Amphibian Specialist Group (ASG) has partnered with governmental and non-governmental organizations and individuals to create new protected areas and minimize further population declines due to habitat fragmentation and loss. In addition to designation of new protected areas, efforts of the ASG include habitat restoration, promotion of ecotourism, and extended amphibian-monitoring programs.

Despite efforts to preserve suitable habitat, biologists became increasingly aware of catastrophic population declines associated with Bd, and more urgent action became necessary when declines were detected in protected areas with minimal risks of habitat loss and overexploitation. Batrachochytrium dendrobatidis is a parasitic fungus that disrupts the bodily processes of its amphibian hosts, resulting in lethargy and ultimately death. Although the exact origins of this pathogen are currently debated, Bd has been detected throughout the world and linked to dramatic amphibian population declines and extinctions (Skerratt et al . 2007).

Due to the rapidity with which Bd invades amphibian communities, swift conservation action was deemed necessary to prevent extinctions; consequently, many institutions realized the necessity of collecting wild individuals prior to the arrival of Bd with the hopes of establishing captive populations. The Amphibian Ark, for example, represents a joint effort between the ASG, the World Association of Zoos and Aquariums, and the IUCN/SSC Conservation Breeding Specialist Group. Members of these organizations worldwide participate in captive amphibian husbandry and breeding programs using wild-caught individuals (Figure 5-6). In concert with such activities, some facilities are also addressing the possibility of 'biobanking' activities, such as cryogenically preserving the sperm and eggs of imperiled species or maintaining living cell lines for future use. While some researchers are dedicated to maintaining captive populations, others are actively investigating potential treatments for Bd or preventative measures. Treatment methods are currently being investigated for amphibians already infected with Bd (Berger et al . 2010), and findings that certain bacteria confer Bd resistance have led some researchers to examine the viability of 'seeding' amphibians with protective bacterial coatings prior to reintroduction efforts (Becker and Harris 2010). Also, biologists are increasingly advocating for more rigorous chytrid monitoring protocols to prevent further spread of this pathogen, such as efforts in the United States to incorporate amphibians into the Lacey Act (1900), a federal mandate that would require them to be certified as disease-free prior to importation.

Throughout the current amphibian extinction crisis, increasing public awareness has been a critical component of conservation efforts. Amphibians typically do not receive the attention bestowed upon more charismatic megafauna, such as pandas and tigers, despite their significant economic, ecological, and aesthetic values. In a worldwide effort to bring amphibian population declines to the forefront, the Amphibian Ark declared 2008 as the "Year of the Frog," a time in which conservationists showcased amphibian diversity in zoos and aquaria while detailing their current plight. In addition, some conservation efforts, such as Project Golden Frog, utilize attractive or otherwise conspicuous amphibians as flagship species with which to garner public interest and local pride in endangered species and promote local activism (Figure 7). The ASG's 'Metamorphosis' initiative utilizes artistry to promote increase public recognition of connections between the plight of amphibians and that of humanity. Biologists have also solicited direct public involvement through citizen science programs wherein non-scientists can participate in crucial amphibian population monitoring efforts; examples of these efforts include ASG's Global Amphibian BioBlitz, Nature Canada, and Environment Canada's FrogWatch, the United States Geological Survey's North American Amphibian Monitoring Program, and the AZA's FrogWatch USA. Finally, continued research highlighting the critical ecological and economic roles amphibians play in ecosystems, such as transferring energy through food webs and reducing insect populations (Davic & Welsh 2004), has been important in cultivating popular interest in the current extinction crisis.

References and Recommended Reading

Berger, L., Speare R. et al . Treatment of chtridiomycosis requires urgent clinical trials. Diseases of Aquatic Organisms 92 , 165-174 (2010).

Collins, J. P. & Storfer, A. Global amphibian declines: sorting the hypotheses. Diversity and Distributions 9 , 89-98 (2003).

Davic, R. D. & Welsh, H. H. On the ecological roles of salamanders. Annual Review of Ecology, Evolution, and Systematics 35 , 404-434 (2004).

Ebenhard, T. Conservation breeding as a tool for saving animal species from extinction. Trends in Ecology and Evolution 10 , 438-443 (1995).

McKinney, M. L. Extinction vulnerability and selectivity: combining ecological and paleontological views. Annual Review of Ecology and Evolution 28 , 495-516 (1997).

Ralls, K. & Ballou, J. D. Genetic status and management of California condors. Condor 106 , 215-228 (2004).

Russell, W. C., Thorne, E. T. et al. The genetic basis of black-footed ferret reintroduction. Conservation Biology 8 , 163-266 (1994).

Skerratt, L. F., Berger, L. et al . Spread of chytridiomycosis has caused the rapid global decline and extinction of frogs. Ecohealth 4 , 125-134 (2007).

Stuart, S. N., Chanson, J. S. et al. Status and trends of amphibian declines and extinctions worldwide. Science 306 , 1783-1786 (2004).

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Nature’s Comebacks—And What’s Still Possible

In its first 50 years, the U.S. Endangered Species Act has played a major role in conserving rare plants and animals in every state. Take a moment to celebrate its success where you live.

April 12, 2023 | Last updated January 03, 2024

Endangered, threatened and recovering U.S. species

Jump to the amazing species comebacks in your state or region.

It took millions of years for the spectacular variety of life to evolve on the North American landscape, influenced by everything from geography to soils to climate and the stewardship of Indigenous Peoples. This complex and interconnected web of life is dwindling fast, but there is still hope.

In the early 1970s, a growing number of people from all walks of life saw the threats to nature, they saw hope and they spoke up. Along with their awareness and activism came a wave of policy actions aimed at safeguarding air, water, and the myriad of living things. Among those actions was the Endangered Species Act , which was signed into law on December 28, 1973.

Tell Congress to Save America’s Wildlife

Support the Recovering America’s Wildlife Act

Facts About the Endangered Species Act

• The U.S. Endangered Species Act was signed into law by President Richard Nixon on December 28, 1973, with overwhelming bipartisan support.
• The act currently protects 1,662 U.S. species and 638 foreign species .
• The act has helped recovery efforts of the American bald eagle, American alligator, whooping crane and many other iconic species.
• 84% of Americans support the Endangered Species Act.

As we celebrate its first 50 years, the Endangered Species Act has proven to be one important tool to help rare species recover. The act has played a role in the comebacks of  many species you see below. 

The Endangered Species Act isn't perfect, and threats to biodiversity remain enormously challenging. Many actions are needed to deliver the right policies, funding, and science, along with solutions for the tandem crisis of climate change. The  Recovering America’s Wildlife Act  is one measure Congress can pass to help keep common species common and prevent others from becoming rare. Another path to safeguarding biodiversity is the  Global Biodiversity Framework  agreed upon at the December, 2022, UN Biodiversity Conference in Montreal. And in the U.S., President Biden has stated his commitment to  America the Beautiful , a national initiative to conserve and restore 30% of the country's lands and waters by 2030.

We know what success can look like. We know—from the Endangered Species Act and many other initiatives to restore habitat and wildlife—that species can make a comeback.  Here are just a few.

Endangered & Recovering Species in Eastern States

Select the photos to discover more about plants and animals in your state and across the country!

Connecticut

Peregrine falcon, Falco peregrinus

The peregrine falcon is a crow-sized bird that can be found on every continent except Antarctica, making it one of the most widely distributed raptors in the world. It catches its prey—mainly small birds—in midair after diving from great heights. During these dives, a peregrine falcon may reach speeds of more than 200 mph, making it the fastest animal on the planet.

Range: Peregrine falcons can be found along shorelines, cliffsides, mountains, river valleys, and cities across the globe.

Where to see: In Connecticut, peregrine falcons can be found along the coast and in cities like Hartford, New London, and Bridgeport, where they nest on tall structures.

Conservation approach: Like many raptors, peregrine falcon populations suffered steep declines due to the use of the pesticide DDT, which caused thinning of their eggshells. The population collapse was successfully reversed through captive breeding programs across the country. Peregrines had disappeared from Connecticut until 1997, when birds bred as part of a reintroduction project in New York relocated across state lines.

Significance for habitat/biodiversity: Peregrine falcons prey on small to medium birds and insects. They are noteworthy for having adapted especially well to living in cities, where they prey on pigeon populations.

Learn more: Connecticut DEP peregrine falcons Connecticut Audubon peregrine falcons

Reviewed by Shelley Green, Director of Conservation Programs, The Nature Conservancy in Connecticut and Holly Drinkuth, Director of River and Estuary Conservation, The Nature Conservancy in Connecticut.

Photo Credit:  Janet Haas

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Staggerbush, Lyonia mariana

Known for its delicate clusters of white and pink tubular flowers, staggerbush is a low-lying shrub found in coastal areas, preferring moist sandy or peaty soils and plenty of sun. The species has declined across much of its historic northern range due to habitat fragmentation and is considered imperiled in Delaware, critically imperiled in Pennsylvania, and extirpated in Connecticut. However, the species has been re-emerging recently at TNC’s  Ponders Tract Preserve  thanks to our conservation efforts.

Range: Eastern United States, primarily in coastal areas of the Mid-Atlantic and the Southeast.

Where to see: Ponders Tract  in TNC’s Pemberton Forest preserve in southern Delaware.

Conservation approach: Prescribed fire is an important element of TNC’s conservation approach in Delaware. Returning fire to the landscape at Ponders Tract has helped thin out dense brush and restore soils by recycling nutrients. This has allowed wild native plants such as staggerbush to mount a comeback, which in turn helps improve biodiversity at the site overall. Ponders Tract serves as a crucial stopover for neo-tropical birds such as the black-and-white warbler and the ovenbird. Hessel’s hairstreak, a rare and threatened butterfly, has been observed in this portion of the preserve, and the endangered Delmarva fox squirrel has also been documented nearby.

Significance for habitat/biodiversity: Jason Davis, a biologist with the Delaware Division of Fish & Wildlife, recently surveyed the return of staggerbush at Ponders Tract since several rare insects rely on these plants to complete their life cycle. “It’s a good sign when a state wildlife biologist wants to visit TNC’s preserves to look for rare and endangered species,” says Delaware Stewardship Manager Natasha Whetzel.

Reviewed by Keith Fisher, Director of Conservation, Pennsylvania and Delaware.

Photo Credit:  James Gaither/Flickr

Alewife, Alosa pseudoharengus

Like all herring species, the alewife is an anadromous fish—it spawns in freshwater, migrates to the ocean for its adult life, and swims back upstream to reproduce in fresh water. Each spring, alewives migrate in huge numbers up rivers and streams to spawn, a life cycle that nourishes many other species and has provided Indigenous Peoples with food for thousands of years.

Range: Atlantic coastal rivers from Labrador to South Carolina. Alewives have has been introduced into a number of Great Lakes waters as non-native species.

Where to see: There are now a multitude of  places to see migrating alewives along the coast of Maine, for example the Damariscotta Mills Fish Ladder Restoration in Nobleboro and Newcastle, usually from mid-May through early June. Also, check out the Maine Alewife Trail Map .

Conservation approach: TNC, along with many partner organizations and state and federal agencies, have worked in recent decades to remove barriers to the migration of alewives and other native sea-run fish so that their populations can once again become self-sustaining. Alewives co-evolved with Atlantic salmon and have benefited from, and play an important role in efforts to restore federally endangered salmon in Maine. Removing dams and replacing under-sized culverts have allowed alewives to stage a spectacular comeback to rivers and streams throughout New England, especially in Maine. There are now rivers in Maine that support runs well over 2 million fish annually!

Significance for habitat/biodiversity: Restoring river connectivity has not only helped alewives return to their native waters, it has helped other sea-run fish, such as blueback herring, Atlantic salmon, American shad and American eel. Their collective comebacks also benefit predators, such as river otters, bald eagles, osprey, and striped bass, among others. Healthy alewife numbers in Maine rivers have allowed a revitalization of a long tradition of spring harvests for food and lobster bait.

Reviewed by Molly Payne Wynne , Maine Freshwater Program Director.

Photo Credit:  Bridget Edmonds/TNC

Canby’s dropwort, Oxypolis canbyi

Canby’s dropwort is a perennial forb belonging to the mint family. The "quill-like" hollow leaves and the thick, corky wings that extend out from the margins of the fruit are the most distinctive features of the plant. It was listed as federally endangered in 1986 and has continued to decline as seasonal wetlands in its native range have been drained for commercial and agricultural development.

Range: The historical range included Delaware, Maryland, North Carolina, South Carolina and Georgia. Today, only 25 populations are known to exist within this historical range.

Where to see: This plant grows in Coastal Plain habitats, including pond cypress savannas, wet meadows, and depressional wetlands. The only known population of Canby’s dropwort in the state of Maryland is located on  TNC’s Crescent Preserve , located in Dorchester County, Maryland. Due to the fragility of this ecosystem, the exact location of the preserve is not advertised, and the preserve is closed to the public.

Conservation approach: TNC has documented the effects of reintroducing fire to the only population of Canby's dropwort in Maryland, found on TNC's Crescent Preserve, and monitored the resulting population increase. After cutting woody vegetation, 3.74 times more stems of dropwort per year were produced over the baseline of no intervention. Subsequently, after fire was reintroduced, 10.80 times more dropwort stems per year were produced in comparison to the time period after cutting woody vegetation. The prediction showed that in the absence of intervention with fire, dropwort stem production would likely have declined.

Significance for habitat/biodiversity: Canby’s dropwort is an indicator species for the diminishing presence of seasonal wetlands and the many species that call those ecosystems home. Tracking their population health can help scientists better understand the conservation strategies that are best suited to their unique habitat types.

Reviewed by  Deborah Landau , PhD, Director of Ecological Management, Maryland/DC chapter.

Photo Credit:  Gabriel Cahalan

Massachusetts

Moose, Alces alces

Historically, moose roamed the forests of Massachusetts, but by the mid-1800s, forest clearing and unregulated hunting led to their disappearance. Moose began to return to Massachusetts around the 1980s, expanding south from neighboring states. Thanks to the conservation of forested landscapes, there are now nearly 1,000 moose in western and central Massachusetts.

Range: Moose are found across North America from the maritime provinces in eastern Canada to the western edge of Alaska, and south into the northern United States. They reach the southern edge of their range in Massachusetts.

Where to see: TNC’s Coles Brook Preserve is an ideal location for moose, with a mosaic of forest and wetland habitat. Nearby October Mountain State Forest and the 100,000 acres of forest surrounding the Quabbin Reservoir , metro Boston’s water supply, have abundant moose.

Conservation approach: Conserving large and intact landscapes across Western and Central Massachusetts is critical to ensuring resilient moose populations in Massachusetts. These diverse landscapes allow moose to find suitable habitat as the climate changes. Addressing climate change is critical, as moose at the southern edge of their range suffer from warmer temperatures in both summer and winter. Supporting the ability of moose to safely cross roads will enhance their viability and public safety as well.

Significance for habitat/biodiversity: Because moose in Massachusetts are at the southern edge of their range, moose adapted to this climate may be best suited to cope with the impacts of climate change. Moose browsing of trees and shrubs keeps wetland and upland habitats open for grasses, wildflowers and species that depend on these habitats.

Learn more: Moose in Massachusetts

Reviewed by Andy Finton, TNC’s conservation ecologist in Massachusetts.

Photo Credit:  Sally Naser

New Hampshire

Small whorled pogonia, Isotria medeoloid

This rare and delicate orchid is native to the Appalachian Mountains and the Great Lakes region. It has very specific habitat needs, living in very small populations (sometimes only a few dozen stems) in hardwood and conifer-hardwood forests.

Range: Southern Maine south to Georgia, west to southern Ontario, Michigan and Tennessee.

Where to see: Several TNC preserves in New Hampshire protect populations of small whorled pogonia and its habitat. As this species is an orchid and vulnerable to plant collectors, we do not cite its locations.

Conservation approach: Because some populations in New Hampshire are quite large, the state is key to conservation efforts. TNC has played an important role by supporting the US Fish and Wildlife Service and other conservation partners in identifying populations and protecting the plant’s habitats. Scientists have also studied forest dynamics that can benefit or harm small whorled pogonia populations. In 1994, its designation under the Endangered Species Act changed from endangered to threatened.

Significance for habitat/biodiversity: Among the main threats to this rare orchid are conversion of its forest habitat to development, forest canopy closure, and collectors who dig them up. Researchers are studying the relationships of small whorled pogonia with fungi and pollinators, an example of the many nuanced interconnectedness of species and ecosystems.

Reviewed by Jeff Lougee, TNC’s director of land stewardship management in New Hampshire.

Photo Credit:  Jeff Lougee/TNC

Osprey, Pandion haliaetus

Ospreys, or “fish hawks,” are large raptors that migrate to New Jersey’s coastal salt marshes to breed and raise young every summer. Dark brown on their backs and wings, and light beige on the rest of their bodies, these birds have reversible toes with sharp talons to catch their favorite meal—fish.

Range: Found on all continents except Antarctica. In North America, osprey range extends from Alaska to Baja California, and along the Atlantic coast from Labrador to Florida.

Where to see: TNC’s South Cape May Meadows Preserve in New Jersey is home to a nesting osprey pair with their own seasonal streaming camera.

Conservation approach: Banning DDT, adding the species to the New Jersey state endangered list and building nesting platforms to replace lost habitat allowed ospreys to rebound from a nadir of just 53 nesting pairs in the early 1970s to population numbers beyond historic levels—706 nesting pairs in the most recent (2021) census. TNC’s NJ team supports ospreys today through banding, monitoring, data collection, nesting platform maintenance and raising awareness through communications.

Significance for habitat/biodiversity: Ospreys maintain healthy fish populations and, because they are sensitive to contaminants, are environmental indicators for the condition of rivers, bays and estuaries relied upon by other wildlife and people.

Reviewed by Eric Olsen, TNC’s director of conservation in New Jersey.

Photo Credit:  TNC

Atlantic menhaden, Brevoortia tyrannus

Also known as pogy, mossbunker or bunker, the Atlantic menhaden is a tiny fish essential to the diets of much larger fishes including striped bass, bluefish and tuna, as well as marine mammals like whales and dolphins. Often called “the most important fish in the sea,” this keystone species is essential for people and wildlife—a healthy ocean and a strong coastal economy both depend on plentiful menhaden.

Range: Coastal waters from Canada to northern Florida.

Where to see: Years of hard work and collaboration by a diverse coalition of fishers, scientists and environmental advocates, including The Nature Conservancy, helped to set harvest limits on menhaden. Since then, the menhaden population has rebounded along the East Coast.

Conservation approach: The Atlantic menhaden fishery was basically unregulated until 2012, when harvest limits were first set in response to declines in the menhaden population. Since that regulation went into effect, the menhaden population has been rebounding and expanding back into their historic range. This was a huge step forward that came about after many years of collaboration and advocacy by many groups, including TNC staff in New York, Virginia, and other regions along the East Coast.

In New York, our team then worked to pass a state law in 2019, protecting menhaden and the animals, fisheries, and whale watching businesses that rely on menhaden being abundant, from purse seine fishing while they are in New York waters (all estuaries and out to 3 miles in the Atlantic).

Thanks to the combined efforts of marine biologists, recreational anglers, bird watchers, whale enthusiasts and commercial fishermen, the Atlantic States Marine Fisheries Commission’s Atlantic Menhaden Management Board unanimously voted to change how it manages the fishery in 2020. By adopting a holistic approach that takes the health of the surrounding ecosystem into account, these regulations have helped to grow a resurgence of menhaden over the last several years.

Significance for habitat/biodiversity: Menhaden eat by filtering tiny plants and particles from the water, a process Carl LoBue, TNC’s New York oceans and fisheries director, describes as “turning sunlight into whales.” Thanks to menhaden, whales have returned to New York Harbor, offering New Yorkers and tourists from around the world breathtaking sights and an inspiring connection to nature.

New York now has thriving whale watching businesses, and dolphins chasing menhaden along New York and New Jersey beaches has almost become expected. In Maine, where menhaden used to arrive in refrigerated trucks from the Mid-Atlantic to be used as bait for the highly valued lobster fishery, they now arrive swimmingly by their own accord.

With whales returning to the busy waters off New York, the need has shifted to how to address important questions concerning vessel traffic and their safety, a dialogue that TNC is currently engaged in.

Learn more: Video: Foraging the High Seas NOAA Species Directory: Atlantic Menhaden

Reviewed by Carl LoBue, Oceans and Fisheries Director, The Nature Conservancy in New York.

Photo Credit:  Artie Raslich

Pennsylvania

Bog turtle, Glyptemys muhlenbergii

The bog turtle is one of North America’s smallest turtles, measuring about 3 to 5 inches long with distinctive yellow-orange spots on each side of its head. Bog turtles thrive in isolated wetlands with acidic, wet soil, thick moss and deep layers of mud. Once ubiquitous in the eastern United States, the bog turtle is now federally threatened nationally and endangered in Pennsylvania due to widespread habitat degradation.

At TNC’s Acopian Preserve in southeastern Pennsylvania, spring-fed mountain streams form soft, muddy wet meadows that contain clumps of grassy tussock sedges and other low-lying vegetation. It’s combination of natural elements creates ideal habitat for bog turtles.

Range: Two distinct populations: the first in New York, Connecticut, western Massachusetts, Pennsylvania, Delaware, and Maryland; the second in parts of Virginia, North Carolina, and Georgia.

Where to see: TNC’s Acopian Preserve in Pennsylvania. Note: the location of this preserve is not disclosed to the public due to fragile habitat and elevated risk of poaching turtles for the illegal pet trade.

Conservation approach: Over the years, TNC has implemented prescribed burns, cleared trees, returned grazing to the landscape with cattle and goats, and conducted annual surveys and a radio telemetry study that documented bog turtle locations, hibernation, travel patterns and habitat use within the preserve. A small group of turtles residing in the preserve have been tagged with small, computerized chips to help with tracking, monitoring and managing populations throughout their life cycle.

Significance for habitat/biodiversity: The bog turtle has biological and cultural significance as one of the smallest turtles in the United States. The overall population also serves as a litmus test for the health of wetland areas generally, since the turtles are directly impacted by tall invasive plant species that block out adequate sunlight for basking. The turtles at the Acopian Preserve have been the subject of study since 1969. In the 2020 field season, two bog turtles were captured that were determined to be at least 62 years old. In the 2022 field season a 57-year-old bog turtle was captured. These are the oldest documented bog turtles anywhere in their range.

Learn more: Endangered Bog Turtle Monitoring with The Nature Conservancy

Reviewed by Keith Fisher, Director of Conservation, TNC Pennsylvania and Delaware.

Photo Credit:  Gates Rhodes

Rhode Island

American burying beetle

Nicrophorus americanus

Known as “nature’s undertaker,” the American burying beetle is the largest carrion beetle in North America, easily identified by its size and striking orange and black markings. Typically found in open field and grasslands, they show a high degree of parental oversight while raising their young, like honeybees.

Range: They were once common from Maine to Texas, but now the only naturally occurring population east of the Mississippi River is found on Block Island, Rhode Island. Scattered populations are found in South Dakota, Nebraska, Kansas, Oklahoma, and Arkansas.

Where to see: Several TNC preserves on Block Island protect the American burying beetle and its habitat. As this species is a large, charismatic beetle and vulnerable to collectors, we do not cite specific locations.

Conservation approach: The beetles were thought extinct by the 1980s, but rediscovered on Block Island and put on the endangered species list in 1989. TNC has worked with state and federal partners since 1991 to conserve critical habitat on the island. The population is stable, but dependent on habitat management and direct human intervention (providing quail carcasses). The Block Island beetles provide a source population to recolonize other locations in the eastern U.S. In 2020, they were “downlisted” to threatened.

Significance for habitat/biodiversity: A nocturnal insect, the American burying beetle is threatened by light pollution, pesticide use, habitat loss, and competition for carrion. Its sharp decline followed the disappearance of the passenger pigeon, whose chicks served as carrion. Scientists have found that 30% of all American burying beetle broods now rely on ring-necked pheasants, gamebirds that were introduced as the passenger pigeon was going extinct.

Learn more: American Burying Beetle Recovery Program—Roger Williams Park Zoo R.I. state insect moved off endangered species list, but not everyone sees it as a victory , Providence Journal, 9/3/20

Reviewed by Scott Comings , TNC’s associate state director in Rhode Island.

Photo Credit:  Clair Comings

Little brown bat, Myotis lucifugus

This aptly named bat weighs as much as six or seven standard-size paper clips. It generally spends winters hibernating in colonies in caves or mines, and disperses in spring and summer, roosting in barns, under shutters and other human structures or under peeling bark. At night, this bat is a voracious insect-eater.

Range: Throughout northern U.S. and into Canada. Not found in southern Great Plains.

Where to see: While little brown bats usually hibernate in caves, they are sensitive to human disturbance. Many state agencies and other owners of cave entrances have closed access to caves, in part to help thwart the spread of white-nose syndrome, the disease that has decimated bat populations.

Conservation approach: Like so many other North American bat species, populations of the little brown bat declined dramatically since the 2006 onset of white-nose syndrome. The fungal disease has wiped out as much as 90% of little brown bat populations in their caves, old mines and other places where they hibernate over winter (called hibernacula). In Vermont TNC has been working with Vermont Fish and Wildlife to help monitor bat populations. Though the bat's populations are still significantly down from pre-white-nose syndrome, there are signs that their numbers are stabilizing or increasing, possibly by gradually gaining genetic resistance to the disease.

Significance for habitat/biodiversity: The bat's voracious night-time appetite provides a control for populations of beetles, flies, moths, ants and other insects.

Reviewed by Alyssa Schuett, Vermont Fish and Wildlife.

Endangered & Recovering Species in Western States

Sea otter, Enhydra lutris

The sea otter is a marine mammal that spends almost the entirety of its life at sea. Growing to 80 pounds or more, the sea otter is often seen floating on its back while crunching away on shellfish prey found in frequent dives to the seafloor. Sea otters have no blubber layer as other marine mammals do but no other mammal has such dense and insulating fur.

Range: Its original range runs along a Pacific coast arc reaching from present-day California, through regions of Alaska’s Alexander Archipelago and the Aleutian Islands, and eastward through the Kamchatka coast and south to Japan’s northernmost island of Hokkaido.

Where to see: Sea otters are common in many accessible coastal areas in Southeast Alaska, including Glacier Bay National Park, and in Southcentral Alaska, such as Kenai Fjords National Park.

Conservation approach: Sea otter populations were once decimated throughout their Bering Sea range due to a commercial fur trade that began in the 18th century. In Alaska, sea otters have rebounded and are now abundant in many coastal areas. Some efforts at transplanting sea otters in past decades appear to have helped reestablish local populations. These abundant sea otter populations are sometimes in competition with local Indigenous subsistence traditions which have long relied on shellfish such as clams, crabs and mussels.

Significance for habitat/biodiversity: Sea otters are a keystone species in their coastal ecosystems. By controlling the populations of green sea urchins, which graze on undersea kelp forests, sea otters help ensure healthy nursery habitats for fish and other species.

Learn more: Alaska Department of Fish and Game page on sea otters

Reviewed by Colin Shanley, Spatial Ecologist, TNC in Alaska.

Photo Credit:  Kiliii Yuyan

Bighorn sheep, Ovis canadensis

The bighorn sheep's compact body is muscular and covered with  chocolate brown fur with a dash of white on the muzzle, rump and belly. While most weigh 160 to 250 pounds, males can weigh more than 350 pounds and stand around 40 inches at the shoulder. They have wide-set eyes that are situated well forward on the head, providing a wide arc of exceptional vision. Their concave hooves allow them to climb steep, rocky desert mountains quickly and easily. These agile animals are well adapted to the arid environment in the west, going several weeks without water while living mostly off grasses and, sometimes, cacti.

Range: Primarily Mojave and Sonoran deserts in Arizona and California. Approximately 1.5 million to 2 million bighorn sheep lived in North America at the beginning of the 19th century; however, only 4% of their historic range remains because of disease from livestock and habitat loss.

Where to see: TNC’s Aravaipa Canyon Preserve in southern Arizona Rocky Mountain National Park in Colorado

Conservation approach: TNC in Arizona collaborates with public land managers to implement controlled burns to help keep their habitat open so they can see and escape from predators such as mountain lions, coyotes and bobcats.

Significance for habitat/biodiversity: Bighorn sheep live in steep mountainous habitat, with ledges sometimes only two inches wide provides cover from predators. Most populations undergo seasonal movements, generally using larger upland areas in the summer and concentrating in sheltered valleys during the winter.

Photo Credit:  Stefen Doucette/TNC

Island bedstraw, Galium buxifolium

Island bedstraw is a long-lived woody shrub with small flowers that lives on coastal bluffs and marine terraces, of Santa Cruz and San Miguel Islands. It is a clear example of “island woodiness,” when soft-tissued herbaceous species evolve on islands to form woody tissue.

Range: The only place on Earth where island bedstraw exists is on two of California’s Channel Islands.

Where to see: Visitors to TNC’s Santa Cruz Island can see island bedstraw. Please stay on established trails or observe from a boat to catch a glimpse of island bedstraw and protect its vulnerable populations.

Conservation approach: Once found on the marine terraces of Santa Cruz and San Miguel Islands, island bedstraw survived on steep cliff faces inaccessible to introduced mainland vertebrate that ate them into oblivion. After the threats were removed island bedstraw began to recolonize areas it had not been seen since the late 1800s. Island stewards and research botanists worked in concert to monitor and assess its status by applying a novel approach developed to survey for invasive plants.

“Recovery doesn’t happen overnight. It takes sound science, collaboration with many partners and, most importantly, commitment.” —John Knapp, Senior Island Scientist with TNC.

Significance for habitat/biodiversity: Compared to the mainland, islands have fewer species, so each species has the burden of playing multiple roles in the ecosystem. From providing food for pollinators to soil remediation and creating habitat for other species, native flora keep islands running. But the more plant species islands lose, the harder it is for their ecosystems to remain resilient and defend against threats like invasive species, increased wildfires, and climate change.

Reviewed by John Knapp, Senior Island Scientist with TNC.

Photo Credit:  Steve Junak/Courtesy of the Santa Barbara Botanic Garden

Preble's meadow jumping mouse

Zapus hudsonius preblei

Known for its remarkable leaps, the Preble's meadow jumping mouse is endemic to riparian ecosystems of Colorado and Wyoming—found nowhere else in the world.

Range: Front Range of Colorado and Southern Wyoming in riparian habitat.

Where to see: You can see the Preble’s meadow jumping mouse at the Phantom Canyon Preserve in the Laramie Foothills near Fort Collins, CO.

Conservation approach: The decline of their habitat due to human interference and development has led to rapid population decline, as they are now a federally threatened species. As part of the North Fork Cache la Poudre Watershed Site Conservation Team, TNC is working to protect habitat and promote species recovery for this critical species. This will be achieved by enhancing healthy riparian corridors that connect suitable habitat throughout the species range and promoting compatible land use.

Significance for habitat/biodiversity: Water-rich, riparian ecosystems support hundreds of species of flora and fauna, including many species of conservation concern. Riparian habitat throughout the semi-arid West is a limited resource and is at risk from land conversion. Altered stream flow, habitat loss, and drought threaten not only Preble’s recovery, but the success of other dependent species.

Reviewed by Chelsea Beebe, TNC Colorado Conservation Ecologist.

Photo Credit:  TNC

Lobeliads, Cyanea sp., Hāhā in Hawaiian

Cyanea sp . is a genus of flowering plants in the family Campanulaceae . The plant is called hāhā in the Hawaiian language. Hāhā grow in moist and wet forest habitat and are largely pollinated by native birds such as the Hawaiian honeycreepers. Unlike most endemic species in Hawai‘i which lost their defenses due to lack of predators, the hāhā evolved with large thorns on the lower part of its new growth. One theory suggests that the thorns are a defense against herbivory  by the moa-nalo, a group of tall flightless ducks that went extinct on the islands within the last 1600 years.

Cyanea fruits are a food source for many endemic insects, which are themselves important food sources for endangered birds such as the Kiwikiu (Maui parrotbill, Pseudonestor xanthophrys ). Cyanea , even with thorny protuberances, are home to many native invertebrates including Hawai‘i’s endemic snails.

Range: Hawaiian lobelioids are endemic to Hawai‘i and found nowhere else on earth. There are multiple endangered Cyanea species across Hawai‘i. Many of them co-evolved with bird species whose curved beaks perfectly match the curve of the Cyanea flowers.

Where to see: Within protected TNC preserves such as Waikamoi on Maui and Kona Hema on Hawai‘i island.

Conservation approach: Cyanea and other endangered plants and animals find a safe haven within TNC’s forest preserves that are free from invasive animals and managed for weeds. TNC maintains and manages forest preserves across Hawai‘i with a focus on passive restoration by removing threats and allowing native systems to recover. Thanks to this work, biologists have been able to plant hundreds of Cyanea in TNC forest preserves, in partnership with the Hawai‘i Plant Extinction Prevention Program.

Significance for habitat/biodiversity: Habitat loss is the key threat to many of Hawai‘i’s endemic species, along with invasive animals and weeds. The Hawaiian lobelioids (the six genera of: Brighamia, Clermontia, Cyanea, Delissea, Lobelia, and Trematolobelia ) represent one of the best examples of adaptive radiation with Cyanea being the most species rich (currently 79 species in the genus).

Learn about the safe haven provided by TNC’s Waikamoi Preserve on Maui and Kona Hema Preserve on Hawai‘i island. See more images of Cyanea species here , here , and here .

Reviewed by Keoki Kanakaokai, Natural Resource Manager, Maui forest program.

Pronghorn, Antilocapra americana

Pronghorn have roamed North America for millennia and are best known as the second-fastest land mammal on Earth. They are hoofed herbivores measuring 3 feet tall and weighing up to 150 pounds.

Range: Many western states, including Idaho, Arizona, Colorado, Wyoming, Montana, Nevada, New Mexico and Utah.

Where to see: You can spot this icon across the West, but we recommend TNC’s Flat Ranch Preserve near West Yellowstone in the summer.

Conservation approach: For millennia, pronghorn have migrated on the same paths in landscapes across Idaho. From the Pioneer Mountains summer range, pronghorn make a journey that is more than 80 miles each way and is among the longest mammal migrations in the lower 48 states. Using GPS collars, biologists tracked pronghorn to map their migratory paths. This information is used by wildlife managers to encourage community land-use planning and land stewardship, and to engage landowners in voluntary land conservation.

Significance for habitat/biodiversity: Pathway obstructions, like fences, pose a dangerous threat because pronghorn eyesight is adapted to seeing things far away, so they have trouble seeing and jumping over fences. Finding a route around these barriers wastes needed energy and calories. Keeping habitat and migration routes open is imperative for the long term success of this species.

Reviewed by Tess O’Sullivan, TNC’s Land Conservation Strategy Lead for Idaho.

Photo Credit:  Steve Dondero

Grizzly bear, Urus arctos

Grizzly bears once ranged across most of western North America. Grizzlies are distinguished from common black bears by the prominent hump above their shoulders, scooped out snout profile and small rounded ears. Grizzlies are omnivores whose diets consist largely of plants including grasses, berries and roots, but they also eat insects and large and small mammals.

Range: Current range in the lower 48 states includes Greater Yellowstone Ecosystem of Montana, Wyoming and Idaho and the Northern Continental Divide Ecosystem. Grizzlies—called brown bears in Alaska—have a far greater range in Western Canada and Alaska.

Where to see: Yellowstone and Glacier National Parks (and surrounding lands).

Conservation approach: Given that a grizzly may have a range as large as 250 square miles, protecting large, connected areas of intact habitat is critical. In Montana’s Crown of the Continent and parts of the Greater Yellowstone, TNC uses land purchases and conservation easements to secure critical habitat and connections between public lands and private holdings such as family ranches. We also work with wildlife managers and landowners to help avoid human-bear conflicts, which can lead to the death of the animals.

Significance for habitat/biodiversity: Historically, grizzlies ranged across much of Montana, but as western settlements grew, remained only in more remote and forested areas. Today, they use a wide range of habitats where food and security are abundant, including meadows, wetlands, streamside zones, forests and alpine areas. Habitat use can range highly between seasons and based on local conditions.

Learn more: Visit Montana Natural Heritage Programs Field Guide for more information.

Reviewed by Dave Hanna, Crown of the Continent Program Director.

Photo Credit:  Loren Merrill/TNC Photo Contest 2019

Amargosa toad, Anaxyrus nelsoni

The Amargosa toad is an incredibly rare species that lives in the Oasis Valley of the Amargosa River, a biologically diverse area at the transition of the Mojave and Great Basin deserts. This medium-sized, short-limbed toad is dependent on water from the river and its springs.

Range: The Amargosa toad is endemic to Nevada and found nowhere else on Earth other than its natural habitat along a 15-mile stretch of the Amargosa River from Beatty to TNC’s 7J Ranch Preserve.

Where to see: Amargosa toads can be found in small ponds and standing pools of water at TNC properties in the Oasis Valley, including Torrance Ranch Preserve , 7J Ranch Preserve and the Beatty Narrows.

Conservation approach: TNC has been working to protect the Amargosa River, home of the Amargosa toad, for almost 40 years, and we have protected more than 1,600 acres of its habitat through acquisition and easements. In 2010, we came together with partners and community members in Beatty to prevent the toad from being listed as an endangered species. The restoration approach we have developed at Torrance Ranch Preserve more than 20 years ago has been successful in attracting and supporting these native amphibians, as well as local and migratory birds, fish and thriving native plant communities. The work being done there has also become a model for how to create and sustain desert wetland habitats and build a coalition of partners dedicated to protecting the Amargosa toad.

Significance for habitat/biodiversity: The species is incredibly rare and threatened by several factors, including habitat loss and degradation, water diversion and invasive species.

Learn more: Cool Green Science: Protecting the Amargosa: From Suspicion to Support for a Desert River

Reviewed by Michael Clifford, Conservation Scientist for TNC in Nevada.

Photo Credit:  Len Warren/The Nature Conservancy

Chiricahua leopard frog

Lithobates chiricahuensis

The Chiricahua leopard frog has a unique color pattern of small, raised cream-colored spots across the body including its thighs. What makes this species different from other leopard frogs is the call it makes to others, which sounds like a snore.

Range: Southwestern New Mexico and southeastern Arizona.

Where to see: You can see the Chiricahua leopard frog at the TNC’s Mimbres River Preserve , near Silver City, NM.

Conservation approach: To protect some of the Chiricahua’s remaining habitat, TNC in New Mexico purchased the Mimbres River Preserve, which includes 600 acres and irreplaceable streamside habitat along 5 miles of river. Additionally, TNC, New Mexico Department of Game and Fish and the U.S. Fish and Wildlife Service have completed habitat restoration projects along the river and in adjacent wetlands. We see the Chiricahua leopard frogs and other critters swimming in open pools.

Significance for habitat/biodiversity: Water withdrawals, river channelization, parasites and pathogens and the introduction of non-native fish species have degraded the amphibian’s habitat. The Mimbres River Preserve provides a safe home for the critters with year-round water flows and an off-channel wetland spring habitat that that provides them a safe home.

Reviewed by  Martha Cooper , Freshwater Director for The Nature Conservancy in New Mexico.

Photo Credit:  Sue Sitko/The Nature Conservancy

Fender’s blue butterfly

Icaricia icarioides fenderi

Found only in the Willamette Valley, Fender’s blue butterfly depends on a threatened wildflower called Kincaid’s lupine.

Range: Willamette Valley.

Where to see: Willamette Valley at TNC’s Willow Creek Preserve in Eugene, OR.

Conservation approach: As of January 2023, the U.S. Fish and Wildlife Service announced the reclassification of Fender's blue butterfly from endangered to threatened under the Endangered Species Act. Fender’s blue butterfly was believed to be extinct in 1937 but was rediscovered in 1989.

For decades, TNC has worked to enhance and restore native prairie on Willow Creek Preserve in Eugene for these and other native prairie species. Working in partnership with other conservation agencies and organizations, TNC led conservation and restoration efforts of native prairie and oak savanna in the Willamette Valley for over three decades. TNC has been instrumental in securing permanent protections for numerous strategic conservation properties through direct acquisition or by securing conservation easements.

Significance for habitat/biodiversity: Native prairie and savanna habitats have become a conservation focus in North America due to recognition of their importance to native plants and wildlife and because of the dramatic loss of these habitats from conversion to agriculture and urban development (Apostol and Sinclair 2006). Further, remnant prairies and savannas are often small, fragmented, and ecologically degraded leading to further declines and loss of native plants and animals. This is particularly evident in the Willamette Valley in Oregon, where over 98% of native prairie and oak savanna habitat has been lost (Noss et al. 1995, Floberg et al. 2004). Without continued active management and restoration, invasive woody and non-native plants would quickly reduce the ecological value of prairie habitat at these sites and reverse conservation gains.

Fender’s blue butterfly only lives in the Willamette Valley and reproduces on only one kind of flower—the Kincaid’s blue lupine. This plant has disappeared in the valley due to a variety of causes from urbanization, agriculture, and non-native plant invasions to the suppression of wildfire.

Reviewed by Jeff Rosier, TNC Oregon Willamette Basin Steward.

Photo Credit:  Matthew Benotsch

Utah prairie dog, Cynomys parvidens

The body of a Utah prairie dog is like a squirrel with short limbs and mid-length tails (1-2.5 inches). Standing approximately 10-15 inches tall and weighing 1-2 pounds, they have light to dark brown fur. Like other species of prairie dogs, the Utah prairie dog is mainly an herbivore, but sometimes eats cicadas and other insects. They live in extended family colonies in networks of underground holes.

Range: They are found only in southwestern Utah, roughly between Bryce Canyon National Park and Cedar City.

Where to see: Bryce Canyon National Park is a great place to see Utah prairie dogs. When you’re there, ask a ranger at the visitor center for the best locations to see prairie dogs in their natural habitat.

Conservation approach: Due to development and disease, the Utah prairie dog was nearly wiped out and listed as endangered in 1973. Now, it’s part of a U.S. Fish and Wildlife Service (USFWS) recovery program designed to ensure healthy populations. TNC in Utah—working alongside the USFWS, Utah Division of Wildlife Resources and others—has helped protect 800 acres of prime prairie dog habitat near Bryce Canyon National Park and another 291 acres north of Cedar City. With TNC managing land and holding an easement on one of these parcels, Utah prairie dogs spotted in these areas can be part of the annual spring count which supports the recovery effort.

Significance for habitat/biodiversity: Utah prairie dogs provide many benefits to people and nature. Their engineered burrows help maintain meadows which support a variety of plants and animals and allow soil to better absorb water and nutrients. They serve as prey for animals including eagles and hawks. Additionally, their burrows are used by other critters.

Learn more: Can Prairie Dogs Talk ( NY Times ) Catch the Wave: Decoding the Prairie Dog ( Scientific American )

Reviewed by Elaine York, TNC's West Desert Regional Director.

Photo Credit:  Donald Hobern/Flickr CC BY 2.0

Columbia Basin pygmy rabbit

Brachylagus idahoensis

In the last two decades, hopeful state and federal wildlife biologists, pygmy rabbit fans, farmers and ranchers, conservation research zoos, and nonprofits have all come together to give the rabbits a fighting chance against seemingly insurmountable odds.

Range: Columbia Basin/Eastern Washington.

Where to see: Eastern Washington at TNC’s Moses-Coulee Preserve Complex (rabbits are only at Beezley Hills & McCartney Creek right now due to wildfire).

Conservation approach:  Starting in 2011, with volunteer help, the Washington Department of Fish and Wildlife fenced in four multi-acre coyote-proof enclosures on shrub-steppe habitat.

Significance for habitat/biodiversity: Since the 1700s, 80% of the sagebrush ecosystem in Washington has been lost to development and farming. And nearly 1 million more acres across the West are lost each year. In its place, cheatgrass—a fast-growing invasive weed—has quickly spread across portions of the region. An aggressive invader, it dries out early each year, making it highly flammable.

Reviewed by Daniel Misch, Arid Lands Manager/Moses Coulee Preserve Assistant Manager.

Photo Credit:  Morgan Heim

Wyoming toad, Bufo hemiophrys baxteri

Wyoming toads are somewhat smaller than their cousins, ranging between 1.75 to 2.75 inches in length. They have bony ridges on the top of their heads that can distinguish them from other toad species. These are carnivorous critters, dining on an array of invertebrates such as beetles, ants, and spiders, and their diet can make them adorably chubby.

Range: Once thriving in wetlands and rivers across the Laramie Basin of southeastern Wyoming, the toad is now found only at the Mortensen Lake National Wildlife Refuge and a few privately owned Safe Harbor properties .

Where to see: Currently, Mortensen Lake NWR is not open to the public, so it is still difficult to view the toad.

Conservation approach: Thought to be extinct in the mid-1980s due to Chytrid fungus, habitat loss, and possibly pesticides, a small population was found in a privately-owned lake. Those toads were gathered and bred in captivity to build back the population. TNC purchased the land and held onto it until it could be transferred to the public at which time the Mortensen Lake National Wildlife Refuge was established. The refuge is one of four sites where the toads have been reintroduced.

Significance for habitat/biodiversity: In the arid climate of southeastern Wyoming, the refuge provides a protected home for the reintroduced toads, which are breeding with success. TNC played an important role in protecting this lake until the refuge could be established.

Reviewed by U.S. Department of Interior.

Photo Credit:  US Fish and Wildlife Service/Creative Commons

Endangered & Recovering Species in the Midwest

Regal fritillary, Speyeria idalia

This striking butterfly, often mistaken for a monarch due to its similar vibrant orange coloring and black markings, is native to tallgrass prairies. As a caterpillar, it has a very specific diet exclusively made up of tender young violet leaves.

Range: Tallgrass and mixed-grass prairies across the central and western U.S.

Where to see: The regal fritillary thrives in tallgrass prairies like our Indian Boundary Prairies and Nachusa Grasslands preserves.

Conservation approach: TNC, partners and supporters are working to bolster habitat and violet food sources across the Midwest, including at our Indian Boundary Prairies and Nachusa Grasslands preserves. At Nachusa, regal fritillaries are using prairie habitat restored as recently as five years ago. While the species remains in decline throughout its historic range, efforts like these prairie plantings that include five violet species and expand large, connected prairie landscapes are setting the stage for a comeback.

Significance for habitat/biodiversity: Like other pollinators, this butterfly’s population has been declining rapidly in the last few decades due to the significant loss of native prairie habitat and its limited larval diet made up only of violets. The regal fritillary has the essential role of a pollinator, bolstering healthy wildflowers that support many other species in the prairie ecosystem.

Learn more: Planting for Pollinators Plant a Pollinator Paradise .

Reviewed by  Elizabeth Bach , Ecosystem Restoration Scientist at TNC’s Nachusa Grasslands Preserve in Illinois.

Photo Credit:  Chris Helzer/TNC

River otter, Lontra canadensis

The river otter is an amphibious mammal known for its grace and playful nature. The otter’s strong swimming skills come in handy when playing in the water or while in pursuit of a meal—be it fish, mollusks or other small invertebrates.

Range: The river otter occurs in much of Canada and the United States, except for portions of the Southwest.

Where to see: Thanks to reintroduction efforts spearheaded by the Indiana Department of Natural Resources (DNR), the river otter was removed from Indiana’s endangered species list in 2005, and it can now be found in more than 80 Indiana counties, far surpassing reintroduction goals.

Conservation approach: In 1995, the DNR began to re-establish healthy otter populations in several watersheds of northern and southern Indiana, including the Blue River in Harrison County. TNC has been very active in the Blue River for more than 20 years, improving water quality for the otter and many other species.

Significance for habitat/biodiversity: River otters were hunted and trapped extensively for their fur in the 19th and 20th centuries, and are still hunted in some places. Conservation and reintroduction efforts are helping populations to recover, and improvements in water quality have permitted river otters to regain portions of their range.

Reviewed by  Matt Williams , director of conservation programs in Indiana.

Photo Credit:  Flickr/USFWS midwest

Bobcat, Lynx rufus

As a medium-sized cat, the bobcat is an adaptable predator that lives in various habitats, including forests, aquatic corridors, and urban edges. The bobcat is a fierce predator that can run up to 30 miles per hour, leap as far as twelve feet, and is a skilled swimmer. It prefers rabbits as a primary food source but eats a variety of other prey species, such as various bird species, small rodents, and deer. The bobcat is identified by distinctive black bars on its forelegs and a black-tipped, stubby, or “bobbed” tail. Superb night vision and strong scent capabilities help them become excellent hunters in low-light environments.

Range: The bobcat is native to North America and found throughout the continent.

Where to see: There is now a multitude of places to have the opportunity to see bobcats, especially in the southern part of Iowa, like the Land of the Swamp White Oak , a high-quality floodplain project area in Muscatine County, or Grand River Grasslands , an important prairie ecosystem in south-central Iowa. Bobcats are common in the western part of the state and can be found at Broken Kettle Grasslands Preserve and throughout the Loess Hills.

Conservation approach: Bobcats were once common throughout Iowa but quickly diminished and were extirpated from most of the state in the early 1900s due to habitat degradation and unregulated hunting. By the late 1970s, bobcats became a protected species and were listed as endangered on Iowa’s threatened and endangered species list. State protection allowed bobcat populations to expand and grow slowly naturally, and by the early 2000s more sightings in Iowa began to occur, mainly in the southern portion of the state.

Significance for habitat/biodiversity: Bobcats are effective predators of any habitat and play an essential ecological role in helping control small herbivores such as rodents and rabbits. A highly versatile territorial cat species, bobcats prefer habitats with thick vegetation and ample space for independent home ranges. They require natural shelters, such as outcrops, fallen logs, or dense undergrowth. TNC in Iowa is working to restore contiguous wildlife corridors that protect large tracts of habitat, which will help expand bobcat ranges and grow bobcat populations throughout the state.

Reviewed by Scott Moats, Director of Lands & Fire Manager Iowa/Missouri.

Photo Credit:  Kent Mason

Least tern, Sternula antillarum

The least tern is a small seabird, similar to a gull, but with a straight beak. On the eastern and western coasts, least terns stick to sandy beaches, but in the interior United States, least terns use sandbars in rivers, salt flats and gravel islands to nest. The interior population was listed as an endangered species in 1985, but thanks to recovery efforts was delisted in 2021.

Range: Least terns hug the west and east coasts of the United States during breeding and migration and winter in Central America.

Where to see: Each summer, least terns can be observed along Kansas River , where sandbars provide critical nesting habitat and abundant fish feed adults and chicks alike.

Conservation approach: Key to recovery for the least tern was determining what the species required for habitat and then preserving and enhancing that habitat. Managing water levels, such as from dam releases, helps prevent the loss of chicks and nests on river sandbars. Restricting human and vehicular access and modifying construction activities within the river system were managed through U.S. Army Corps of Engineers programs. In 2021, the U.S. Fish & Wildlife Service removed the inland population of the least tern from the federal list of endangered and threatened wildlife because of its recovery.

Significance for habitat/biodiversity: Much like a canary in the coal mine, the decline of birds is often an early warning that something in our natural world needs attention. With least terns, it was clear that the way humans were managing rivers was impacting the bird’s populations—but least terns weren’t the only victim. Bringing back more natural conditions for these rivers saw the recovery of the species but it also benefits other wildlife and improves water quality.

Learn more:   U.S. Fish & Wildlife species profile

Reviewed by Heidi Mehl, director of water and agriculture programs in Kansas.

Photo Credit:  Don Sias

Cisco, Coregonus artedi

Cisco are “forage” fish that provides an important food source for larger fish like lake trout. Historically, they were the most harvested fish in the Great Lakes during the commercial fisheries boom of the late-1800s and early-1900s. Cisco require cold-deep water where they feed on zooplankton and sometimes small fish.

Range: Cisco can be found in the Great Lakes, in cold inland lakes in the Great Lakes Region and throughout much of Canada.

Where to see: Anglers catch cisco where they are abundant, including Lake Michigan near Elk Rapids and Charlevoix, Michigan, Lake Huron around the Les Cheneaux Islands and Drummond Island, and in the St. Mary’s River. You can catch cisco in some inland lakes, but those populations are highly threatened by pollution and climate change.

Conservation approach: TNC partnered with the Michigan Department of Natural Resources, the Little Traverse Bay Band of Odawa Indians, Central Michigan University and the Sioux Tribe of Chippewa Indians to study the number of cisco in Lake Michigan beginning in the early 2000s, confirming their numbers and range have increased significantly. Today, partners are continuing to monitor cisco populations and looking for opportunities to restore spawning reef habitat to further help increase cisco populations in Michigan.

Significance for habitat/biodiversity: From invasive species to overharvesting to environmental degradation, cisco went through it all and the impact it had on their population was devastating. As a forage fish, cisco are an important part of the Great Lakes food web. They are also historically an important food source in the Great Lakes, desired both recreationally and commercially.

Learn more: Elk Rapids Reef Restoration Wildlife Action Plan: Great Lakes Ciscoes Wildlife Action Plan: Inland Cisco Lakes Resurgence of Cisco in Lake Michigan

Reviewed by Matt Herbert , senior conservation scientist in Michigan.

Photo Credit:  Paul Vecsei

Bald eagle, Haliaeetus leucocephalus

The bald eagle could easily be a poster child for nature's comebacks in the U.S.

Mature bald eagles have the classic white head and tail, yellow and crooked beak, and black body. An adult can weigh more than 13 pounds and have a wingspan of 6 to 8 feet.

Often found around large waterbodies, the bald eagle's diet is mostly fish, but also has an opportunistic diet of mammals, birds and even reptiles.

Range: The bald eagle's range includes most of North America, including a large part of Canada and northern Mexico. The species can be found in every state in the continental U.S. and all Canadian provinces.

Where to see: Among many great places to see bald eagles in Minnesota are the Mary Macdonald Preserve at Horseshoe Harbor and St. Louis River .

Conservation approach: In Minnesota and Wisconsin, which boast the largest populations of nesting bald eagles in the Lower 48, they are especially a point of pride. Decades ago, this national symbol was at risk of extinction due to habitat loss, illegal hunting and widespread use of DDT, a once-popular chemical insecticide. When DDT was banned in the U.S. in 1972, the number of known active nests in Minnesota was just over 100. In the time surveys concluded in 2006, the number of active nests was estimated at more than 1,300 and by 2007 there were an estimated 2,300-plus pairs in Minnesota. In 2007, the bald eagle was officially removed from the U.S. Endangered Species List. Today, TNC proudly works with partners to protect important habitat that benefits bald eagles, including in the Northwoods, the Driftless Area and the Mississippi River’s headwaters area .

Significance for habitat/biodiversity: As a species that relies on healthy waters, intact and mature forests, and open country, the bald eagle’s success is tied to conservation of many habitats and the diversity of species found within them. Healthy rivers with strong fish migrations are just one example of many ways that sound habitats and biodiversity contribute to this iconic species’ success.

Learn more: Minnesota DNR: Bald Eagles in Winter Minnesota DNR: Bald Eagles in Summer

Photo Credit:  Marci Lanois/TNC Photo Contest 2022

Topeka shiner, Notropis topeka

A native of the Great Plains, the Topeka shiner is a small silvery-green minnow (less than 3 inches long) with a dark stripe, or lateral band, that runs the length of its body. It was placed on the federal endangered list nearly 25 years ago as its natural habitat deteriorated or was destroyed outright.

The Topeka shiner relies on small prairie streams with good water quality and cool temperatures to survive.

Range: Topeka shiners inhabit parts of six states (Iowa, Kansas, Minnesota, Missouri, Nebraska, and South Dakota) across the Great Plains. They migrate through oxbows and shallow pools of the freshwater streams winding through tallgrass prairies.

Where to see: The Topeka shiner can be found in the headwaters of Little Creek on TNC’s Dunn Ranch Prairie preserve in Hatfield, Missouri. A recently completed fish passage project on Little Creek , has reconnected the upstream and downstream sides of the creek, allowing the little minnow increased habitat to migrate freely.

Conservation approach: In announcing the shiner’s designation as an endangered species in 1998, the U.S. Fish and Wildlife Service noted the minnow’s occupied range had declined by an estimated 80%, with half of that decline occurring during the past 25 years.

At the time, the Topeka shiner had dwindled to only two known streams in Missouri.

In 2013, in partnership with the Missouri Department of Conservation (MDC) and the U.S. Fish and Wildlife Service, TNC launched an effort to restore the Topeka shiner to the headwaters of Little Creek on Dunn Ranch Prairie in northern Missouri. Over 5,000 Topeka shiners from a nearby MDC hatchery were released into the Little Creek watershed.

In 2022, TNC completed a fish passage project on Little Creek , which reconnected more than 5 miles of habitat for the shiner, continuing the commitment to help protect and restore the Topeka shiner to Missouri’s landscapes.

Significance for habitat/biodiversity: The Topeka shiner is an indicator species of environmental quality, meaning its decline is a clear signal of a similar decline in the water quality of our prairie ecosystems. Threats to the minnow include stream channelization, dams, sedimentation, oxbow removal, agricultural runoff, and urbanization and development.

Learn more: U.S. Fish and Wildlife Service species profile

Reviewed by  Rob Hunt , TNC’s director of resilient waters in Missouri.

Photo Credit:  Kimberly Emerson, USFWS

Sandhill cranes, Grus canadensis

The sandhill crane is a large migratory species of crane that can be found throughout North America. The common name of this bird refers to the habitat it prefers, much like that found along the Platte River in Central Nebraska.

Range: Wintering sandhill cranes can be found throughout the southwestern U.S. and migrate to their breeding grounds to nest in the northern U.S., Canada, and even Siberia. With several migratory populations of sandhill cranes, the mid-continent population that comes through Nebraska is the largest, with 80% of all sandhill cranes in the world in that population.

Where to see: A fascinating hourglass migration flight pattern brings cranes to Nebraska between February and April, with mid-March being the peak of the migration. Onlookers can marvel at the spectacular view of more than 1 million birds found along 70 miles of the Central Platte River, like at TNC’s Platte River Prairies , as the cranes rest and refuel for up to three weeks before they continue their northward migration.

Conservation approach: Among the threats to the survival of migratory sandhill cranes are the loss of wetland habitats and unregulated hunting, especially in the early 1900s. According to the North American Breeding Bird Survey , their populations have been increasing at an annual rate of 5% per year since the mid-1960s, due to wetland restoration and abundant food on agricultural lands.

Significance for habitat/biodiversity: Sandhill cranes rely on bare river sandbars for overnight roosting and both crop fields and prairies for daytime feeding. TNC in Nebraska works diligently with partners to maintain river water levels in the Platte River and prevent invasive plants from taking over sandbars. Through stewardship and land management, TNC is successfully protecting over 3,000 acres of land to support a healthy Platte River ecosystem essential for sandhill cranes for years to come.

Reviewed by Chris Helzer, Director of Science.

Photo Credit:  Jim Ridley/TNC Photo Contest 2009

North Dakota

Piping plover, Charadrius melodus

Barely the size of a sparrow, the piping plover is well-disguised among the sands of its habitats along North America's coastal shores and gravel beaches. As a ground-nester on the beach, piping plover eggs and chicks are vulnerable to predation by mammals and other birds. Competition with many human uses in nesting areas can also lead to nesting failure or chick mortality. Since 1985, Northern Great Plains and Atlantic Coast populations have been listed as threatened, and populations in the Great Lakes watershed listed as endangered.

Range: Piping plovers are found in the Great Plains, where they are federally designated as threatened, and in the Great Lakes and Atlantic coast, where they are endangered ( map ).

Where to see: In North Dakota, a good place to see piping plovers is the John E. Williams Preserve near Turtle Lake.

Conservation approach: Piping plovers have very specific requirements for their breeding grounds. TNC established John E. Williams Preserve near Turtle Lake, ND, to protect one of best sites for breeding piping plovers, as the preserve’s gravelly beaches along its alkali lakes provide ideal conditions. Here, TNC is working with experts to develop cost-effective methods to restore habitat and increase the number of nesting plovers at Williams Preserve, including the use of prescribed fire.

Significance for habitat/biodiversity: At John E. Williams, the combination of salty deposits and fluctuating water levels creates large barren areas attractive to piping plovers. The preserve is also attractive to other species, including American avocet, marbled godwit and white-faced ibis.

Reviewed by Chris Gordon, Land Steward/ND Fire Manager.

Photo Credit:  Richard Hamilton Smith

Timber rattlesnake, Crotalus horridus

Timber rattlesnakes are stocky, venomous snakes that grow up to 3 to 5 feet long. Their patterned coloration can range from yellow to dark brown, and they have triangular heads with vertical pupils. They prefer deciduous forests with rocky terrain and canopy openings where they can bask in sunlight.

Range: South central New Hampshire west to southeastern Minnesota and south to eastern Texas and northern Florida.

Where to see: Staff from TNC and the Cincinnati Museum Center are working together with state and private research team members to research and protect populations of timber rattlesnakes at the Edge of Appalachia Preserve in Adams County, Ohio.

Conservation approach: Through field surveys and using telemetry, the team located and tracked a timber rattlesnake on protected land within the Edge of Appalachia Preserve System in 2019. The tracking confirmed timber rattlesnakes using overwintering dens alongside other reptile and amphibian species within the preserve. Long term camera monitoring of these den sites has revealed greater numbers of the species than was previously known. Protecting these dens and overwintering sites is critical to supporting the species.

Significance for habitat/biodiversity: Timber rattlesnakes were once revered and respected by Indigenous Peoples and early Europeans alike. The species was viewed as an important part of the natural system in which they occurred. Today, TNC is working to protect their habitat while helping to educate Ohioans about their importance to the forests of Ohio.

Reviewed by Rich McCarty, Edge of Appalachia Naturalist.

Photo Credit:  Jacob Ian Wall, CC BY-NC 2.0

South Dakota

Black-footed ferret, mustela nigripes

This member of the weasel family is about the same size as a mink, about 18 to 24 inches long and weighing less than 3 pounds. It is the only ferret native to the Americas, and once inhabitated a vast part of North America. They live only among prairie dog colonies and can't survive without the prairie dog.

While only an estimated 300 individual black-footed ferrets exist, this was a species that was thought to be extinct. Thanks to ambitious and persistent conservation efforts, there are signs of success and hope for the black-footed ferret.

Range: Historically the black-footed ferret’s range extended across the Great Plains as far north as Saskatchewan and as far south as Chihuahua. Today, small populations can be found in and near Badlands National Park in South Dakota, and other reintroduction sites in Wyoming and Montana.

Where to see: Conata Basin in the Badlands of South Dakota supports one of the largest self-sustaining populations of black-footed ferrets.

Conservation approach: A small population of black-footed ferrets was discovered in 1981 on a Wyoming rancher’s land. Collaborative efforts by governments, NGOs, local groups and landowners have resulted in successful efforts to reintroduce the animal in select regions, through captive breeding, habitat protection, including land protected by TNC within Conata Basin, and disease management.

Significance for habitat/biodiversity: Because black-footed ferrets depend on prairie dogs for both their food and habitat, grassland restoration has been a critical component in bringing them back. Conservation partners have also focused on disease management, as sylvatic plague and other diseases have taken a toll on black-footed ferret populations.

Reviewed by Julie Brazell, Conservation Coordinator.

Photo Credit:  Bill Allen

Hine’s emerald dragonfly

Somatochlora hineana

Thought to be extinct since the 1930s, an adult Hine’s emerald dragonfly was discovered at a TNC preserve in Door County, Wisconsin, in 1987. This rare dragonfly only lives for three to five years and spends most of its life as a larva, which lives in small streams fed by groundwater.

Range: Parts of Illinois, Michigan, Missouri, Wisconsin and Ontario, Canada.

Where to see: TNC’s Door County preserves— Mink River , Kangaroo Lake , Shivering Sands and North Bay-Mud Lake —are all home to Hine's emerald dragonflies. Door County hosts the greatest abundance of this endangered dragonfly in the world.

Conservation approach: This dragonfly is both state and federally endangered, so state and federal agencies are key to conservation efforts. TNC has played an important role by supporting years of research on the animal’s life cycle and habitat needs. We are using this information to protect groundwater recharge areas and larval habitat. This strategy is key to the species’ survival.

Significance for habitat/biodiversity: Among the major threats to the dragonfly are groundwater contamination and depletion, especially from nearby development. These same groundwater resources also provide well water for residents. Bringing attention to this species is a way to get people thinking about the larger systems that both dragonflies and people need to survive and inspiring action to protect them.

Learn more:   U.S. Fish and Wildlife Service species profile

Reviewed by Mike Grimm, TNC’s conservation ecologist in northeast Wisconsin.

Photo Credit:  Kathy Kirk

Endangered & Recovering Species in Southern States

Red Hills salamander

Phaeognathus hubrichti

The Red Hills salamander is listed as threatened by the U.S. Fish and Wildlife Service. It is approximately 10 inches long, dark brown to dark gray, and is typically found on north-facing steep slopes of ravines and bluffs dominated by hardwood trees.

Range: The salamander’s entire global distribution is confined to six Alabama counties. It is the official state amphibian of Alabama.

Where to see: TNC has worked for many years to protect the Red Hills in Alabama , a part of the state’s Forever Wild Land Trust.

Conservation approach: TNC and our public and private partners are working to protect and restore enough Red Hills habitat to result in the removal of the Red Hills salamander from the federal Endangered Species List. Not coincidentally, such a plan would allow TNC to protect the best of the Red Hill’s unique habitats and many of its other rare or unique species.

TNC has a goal of preserving some 30,000 acres in the Tallahatta Bluffs region over the next decade, and is working with landowners on agreements to protect some 25,000 acres along Big Flat Creek, one of the largest and healthiest Red Hills streams.

Significance for habitat/biodiversity: There are many Red Hills forest types, but one of the most unusual forests of the region combines Appalachian and tropical diversity in surprising ways. The forest along the slopes is often described as a “beech-magnolia” forest. These forests are unusually rich in oaks, hickories, and many other species, but it’s the unusual spectacle of giant beech trees (a symbol of Northern forests) growing happily side by side with towering evergreen Southern magnolias that gives this forest type its name.

The understory has a wide variety of flowering trees and shrubs that many people may associate with forests much farther north, such as mountain laurel, rhododendron, sourwood, mountain hydrangea and leatherwood ( Dirca ). But these plants grow beside some very unusual, virtually subtropical plants, such as the highly fragrant Florida anise (a member of one of the oldest families of flowering plants), titi ( Cyrilla ), and lily-like members of the amaryllis family ( Hymenocallis and Zephyranthes ).

Learn more:  Alabama Forever Wild: The Red Hills Tracts .

Photo Credit:  USFWS

Diana fritillary, Speyeria diana

The state butterfly of Arkansas, Diana fritillary is a large, showy butterfly, once considered at high-risk for extinction in Arkansas. It is dimorphic, with males displaying black near the base of the wings and orange at the outer portions of the wings (on the upper side), and females black at the base with blue on outer parts of the hindwing.

Range: In Arkansas, Diana fritillary are found in the Ozark Mountains, Ouachita Mountains, Arkansas River Valley and Upper West Gulf Coastal Plain. It is also known from the Ozark Mountains in Missouri and eastern Oklahoma and the southern Appalachian Mountains of Virginia, West Virginia, Georgia and Alabama.

Where to see: Many TNC preserves now support populations of this species, including Presson-Oglesby Prairie Preserve in the Arkansas River Valley and Columbus Prairie Preserve in the Blackland Prairie Ecosystem in Southwest Arkansas. Look for males and females flying for about a month in late May and June. Females become active again in September and October when they lay eggs.

Conservation approach: Over the past 30 years, TNC and partners have focused heavily on reintroducing fire as a natural disturbance in the state’s ecosystems. This has restored hundreds of thousands of acres of open habitat, including prairie, glades, savanna and open woodlands. Thanks to this effort, populations of Diana fritillary have rebounded and there is no longer a need to list it as threatened or endangered.

Significance for habitat/biodiversity: Availability of good nectar sources throughout summer and into the fall is important for this species, especially for females which live longer than males. These nectar sources can be found in greater abundance in open, native habitats like tallgrass prairies and glades. Meanwhile, the Diana’s host plants are several species in the genus Viola (violets), many of which are found in wooded and forested areas. Therefore, effective conservation of this species stresses the importance of natural ecotones, landscape mosaics and reoccurring fire, which increase biodiversity and benefit natural communities and other species of conservation concern.

Learn more: For photos, general species information, and recent sightings, see the taxa page on iNaturalist  or the  U.S. Fish and Wildlife Service species profile .

Reviewed by Gabriel De Jong , ecologist and botanist who oversees the Monitoring, Measures, and Adaptive Management Program for the Arkansas Chapter.

Photo Credit:  Cathie Bird/Creative Commons

Florida panther, Puma concolor coryi

The Florida panther is a puma subspecies that is only found in southwest to south-central Florida and nowhere else on earth. With a population estimate of about 200 adults and subadults, it’s one of the most endangered mammals in the country.

Range: The panther’s range once spanned the entire southeastern U.S. but today they are confined to a small area in southwest to south-central Florida that is less than 5% of their historical range.

Where to see: This elusive and critically endangered species is mostly nocturnal and is rarely seen. They live in the forested habitats found in portions of a handful of counties in southwest and south-central Florida.

Conservation approach: Land conservation is a high priority for Florida panther protection and TNC has been working for over 30 years to protect lands critical for the Florida panther to thrive into the future. This includes securing protection through conservation easements along both sides of the Caloosahatchee River, which is a vital link for panthers to naturally migrate from lands south of the river into the ranching and natural lands north of the river. TNC and partners have been working to build protected corridors through the purchase of property and conservation easements to provide a connected landscape for panthers to safely roam and move northward to expand their range.

Significance for habitat/biodiversity: Florida panthers are Florida’s widest ranging land animal, and their large territories are shared with many other species, making them an umbrella species. When we protect land and wildlife corridors for Florida panthers, we are also providing protection benefits to a wide array of plant and animal species that call panther habitat home. Humans also gain from the protection of panther habitat through enhanced and properly functioning ecosystems.

Learn more: Florida Panthers: Crossing the Caloosahatchee Planning for the Prowl: Why it’s Rush Hour for the Florida Panther

Reviewed by Wendy Mathews , TNC Florida senior conservation projects manager.

Photo Credit:  Carlton Ward Jr.

Gopher tortoise, Gopherus polyphemus

The gopher tortoise is one of the planet’s oldest living species and the only native North American tortoise species east of the Mississippi River. Georgia’s gopher tortoise population is now near 40,000 individuals, or 61 viable populations, across the state on protected and actively managed lands.

Range: The gopher tortoise range is from southern South Carolina through the southern half of Georgia, into Florida, and west into southern Alabama, Mississippi and Louisiana.

Where to see: The gopher tortoise can be found at several TNC preserves and project sites, including: • Broxton Rocks Preserve • Charles Harrold Preserve • Chattahoochee Fall Line • Moody Forest Natural Area

Conservation approach: The revitalization of gopher tortoise habitats and populations has been a demonstration in what is possible when environmental partners across the non-profit, governmental, and private sectors work in close partnership. TNC in Georgia is a leader of the Gopher Tortoise Conservation Initiative which includes collaborators such as the Georgia Department of Natural Resources, the Georgia Forestry Commission, Georgia Chamber of Commerce, and dozens of others. Our work has kept the gopher tortoise off of the endangered species list.

Significance for habitat/biodiversity: Gopher tortoises have large, elephantine hind limbs and flattened, shovel-like forelimbs that are uniquely designed to dig burrows up to 40 feet long and 10 feet wide. At least 300 other species also use their burrows, including rare species such as the Eastern indigo snake, gopher frog, Florida mouse, and hundreds of rodents and invertebrates.

Learn more: Gopher Tortoise Conservation Initiative

Reviewed by Dan Ryan, Director of Conservation for The Nature Conservancy in Georgia.

Photo Credit:  Karine Aigner

Rocky Mountain elk

Cervus canadensis nelsoni

The Rocky Mountain elk is a subspecies of North American elk. The Eastern elk ( Cervus elaphus canadensis ) once ranged all over the state of Kentucky, but this subspecies was extirpated by the mid-1800s. When elk were reintroduced to Kentucky by the Kentucky Department of Fish and Wildlife Resources and Rocky Mountain Elk Foundation , beginning in 1997, the subspecies brought over from the western U.S. was the Rocky Mountain elk. These subspecies of elk are genetically similar. Kentucky now has the largest herd of elk east of the Mississippi River.

The Nature Conservancy acquired the Cumberland Forest Project in 2019, including 55,000 acres of prime Kentucky elk habitat where people can once again enjoy elk through wildlife watching, hunting, and the scientific study of this species.

Range: Rocky Mountains and adjacent ranges of the western U.S., with some relocation areas in the eastern U.S.

Where to see: Cumberland Forest Project , Jenny Wiley State Resort Park

Conservation approach: Elk were absent from the Kentucky landscape for more than a century due to unregulated hunting and habitat loss. TNC’s partners reintroduced elk on reclaimed surface mines, which provide the open habitat surrounded by forestland on which elk thrive. The presence of elk on these mine lands has spurred ongoing habitat work by our partners, while TNC’s reforestation efforts on mine lands also benefit the herds. Elk reintroduction has also brought economic benefits to communities in eastern Kentucky.

Significance for habitat/biodiversity: Many species have benefited from the reintroduction of elk and accompanying habitat improvements. White-tailed deer, wild turkey, ruffed grouse and even songbirds benefit from good elk habitat. The Nature Conservancy’s habitat improvement work on the Cumberland Forest Project includes planting hundreds of thousands of trees and hundreds of acres of forbs, grasses, and wildflowers on former mine lands, creating food and cover not only for elk but many other wildlife species.

Learn more: Elk Tours

Reviewed by Danna Baxley , director of conservation for TNC’s Kentucky program.

Photo Credit:  Dave Baker/Kentucky Department of Fish and Wildlife Resources

American chaffseed, Schwalbea americana

American chaffseed is a modest-sized herbaceous plant that occurs in moist longleaf pine habitat on naturally occurring low mounds (“pimple mounds”) and is highly dependent on frequent fire. It was listed as a federally endangered species in 1992, and while it continues to decline, there is hope for its comeback through land protection, careful management of its fire-dependent habitat and other measures.

Range: American chaffseed occurs in seven states along the Atlantic coast: New Jersey, North Carolina, South Carolina, Georgia, Alabama, Florida and Louisiana.

Where to see: CC Road Savanna Preserve , Louisiana

Conservation approach: Several state and federal agencies, organizations, and private landowners are working to protect and manage habitat for American chaffseed.

TNC is working to restore native longleaf pine savanna habitat at CC Road Savanna Preserve through removal of off-site pines and hardwoods, replanting longleaf pine, prescribed burning and control of invasive species. On a broader scale, TNC has been partnering with conservation-minded landowners in the near vicinity, who collectively own several thousand acres being restored to native habitats. Our key conservation strategy calls for protection of at least 10,000 acres in this landscape to ensure long-term viability of the savanna habitat and the many species it supports.

Significance for habitat/biodiversity: American chaffseed is one of many plant species that rely on fire dependent ecosystems—in this case longleaf pine flatwoods. Wildlife species, too, need well-managed longleaf pine forests, such as gopher tortoise and red-cockaded woodpecker. Ensuring the viability of this type of longleaf pine also helps safeguard habitat for those species.

Photo Credit:  Peter Pattavina/US Fish & Wildlife Service

Mississippi

Mississippi sandhill crane

Grus canadensis pulla

About 4 feet tall with a red cap on their heads, Mississippi sandhill cranes are graceful, long-legged birds found exclusively among the wet pine savannas along Mississippi’s Gulf Coast. Unlike their close relatives in the north, this subspecies of sandhill crane does not migrate, but instead stays year-round in the state.

Range: The cranes are found in wet pine savannas of southeastern Mississippi, east of the Pascagoula River to slightly west of the Jackson County line.

Where to see: Staff from TNC and the US Fish and Wildlife Service are working together to research and protect populations of Mississippi sandhill cranes at the Mississippi Sandhill Crane National Wildlife Refuge in Jackson County.

Conservation approach: By the 1970s, the population of Mississippi sandhill cranes had plummeted to only 30-35 birds in the wild, largely due to the loss of their preferred wet pine savanna habitats in southeast Mississippi. To save this species and its home, the Mississippi Sandhill Crane National Wildlife Refuge was created under the authority of the Endangered Species Act in 1975. Since that time, conservationists have been using captive rearing, reintroduction, tracking and monitoring of cranes to help protect and increase their populations numbers. Additionally, because these cranes are homebodies and do not stray far from their wet pine savanna habitat, TNC and other conservation partners are working together to restore and protect the wet pine savannas, primarily through prescribed fire. The paired approach of direct wildlife conservation and habitat protection and restoration has helped the Pascagoula sandhill crane’s population to come back. Today, around 160 Mississippi sandhill cranes live in the wild and their numbers continue to grow.

Significance for habitat/biodiversity: Much like the Mississippi sandhill cranes, the wet pine savannas  that they call home are endangered. As one of the most diverse habitats in the United States, the wet pine savanna is also home to many wildlife and plant species that are native to the Gulf Coast region.

Learn more: TNC: Stories in Mississippi

Reviewed by Becky Stowe, Director of Forest Programs for TNC in Mississippi.

Photo Credit:  Steve Hillebrand/US Fish & Wildlife Service

North Carolina

Red-cockaded woodpecker

Leuconotopicus borealis

Red-cockaded woodpeckers live in mature longleaf pine, which was once the dominant coastal-plain tree from southeast Virginia to eastern Texas. As longleaf forest declined, Red-cockaded woodpeckers became the first bird to be placed on the endangered species list. Today its numbers have grown to the point where it may soon be removed from the list.

Range: Coastal Plain of nine states from Southeast Virginia to East Texas.

Where to see: Disney Wilderness Preserve Calloway Forest Preserve Moody Forest Preserve Peachtree Rock Heritage Preserve Piney Grove Preserve

Conservation approach: Restoring longleaf pine forests, which once covered 90 million acres but shrunk to a historic low of 3.2 million acres, was key to bringing back the red-cockaded woodpecker. TNC is the only organization working across the range to restore longleaf pines, which now span 5.2 million acres, with plantings and controlled burning. Some of the best red-cockaded woodpecker stands remain on military bases. TNC in North Carolina pioneered working with the military to protect, restore, and manage longleaf pine adjacent to Fort Bragg in North Carolina. This approach was also used successfully by TNC in other states to restore red-cockaded woodpecker habitat.

Significance for habitat/biodiversity: Except for tropical rainforests, longleaf pine is unparalleled for its biodiversity. Protecting and managing longleaf forest has benefited not only the red-cockaded woodpecker, but also a host of other species including gopher tortoises and Venus flytraps.

Learn more: Nature Magazine: Pine Country

Reviewed by Chuck Peoples, Conservation Director, North Carolina chapter.

Photo Credit:  Brady Beck

American bison, Bison bison

Also known as American buffalo, the bison were historically found on the rich grasslands from Alaska to the Gulf of Mexico, east to nearly the Atlantic tidewater and from Georgia to New York. The American bison is an herbivore, grazing on sedges and grasses on the prairies, and can weigh 700 to 2,500 pounds.

Range: Historically, bison were found throughout North America, and are now an icon of the Great Plains. Today, most bison live semi-wildly on TNC preserves, in national or state parks or forests, tribal lands and in commercial livestock herds.

Where to see: The Joseph H. Williams Tallgrass Prairie Preserve in Osage County, Oklahoma, is home to TNC’s largest bison herd. Starting with just 300 animals in 1993, the herd has grown to approximately 2,000 head.

Conservation approach: Although never listed as an endangered species under the U.S. Endangered Species Act, the resurgence of American bison across the Great Plains and beyond is a wildlife restoration success story.

Once roaming from modern day Mexico to Canada, bison thrived. Over-hunting by European colonizers, massive plowing of the prairies and non-native diseases forced bison to the brink of extinction. After the deliberate actions of passionate ranchers, American Bison Society and conservationists, the species has rebounded to over 350,000 animals. TNC manages about 5,500 of these animals.

Significance for habitat/biodiversity: Grazing and fire are two of the primary ecological forces in the Great Plains, and their interaction is what creates landscape or habitat diversity. The lush green regrowth following a fire is very attractive to grazing bison, resulting in a fire-induced rotational effect. This “pyric-herbivory,” the interaction of fire and grazing, maintained a dynamic mosaic of landscape patches, thus supporting the rich diversity of prairie plants and animals. Bison also add habitat diversity to the prairie by their wallowing behavior which creates shallow basins that serve as temporary wetlands for other wildlife and water-loving plants. Even their thick patches of hair shed during spring is highly sought after by nesting grassland birds and small mammals.

Reviewed by Bob Hamilton, Tallgrass Initiative Director for TNC in Oklahoma.

Photo Credit:  Morgan Heim

South Carolina

American alligator

Alligator mississippiensis

The American alligator is the official state reptile of Florida, Louisiana and Mississippi, but it’s found across the entire coastal Southeast United States. Decades ago, the American alligator population was threatened both by extensive hunting for their hides (to be made into belts, shoes and purses) and the drainage and clearing of wetlands for competing land uses, such as building homes or growing agricultural products. They were one of the first animals protected under the Endangered Species Act of 1973.

Range: From coastal North Carolina south to Florida, wrapping around the Florida peninsula and up through the Gulf Coast of Texas.

Where to see: Alligators thrive in coastal wetlands and can be found wherever there is fresh water along the South Carolina coast. One of the best places to spot them—especially sunning themselves on a warm day—is a conservation region known as the ACE Basin . This combined basin of the Ashepoo, Combahee and Edisto rivers is located between Hilton Head Island and Charleston.

Conservation approach: American alligator populations have fully rebounded since the 1970s, and—after being removed from the endangered species list in 1987—they are now listed as a species of “least concern” for extinction. This comeback has come thanks to limits placed on alligator products and hunting, as well as robust protection and restoration of the alligator’s natural wetland habitat. In South Carolina’s ACE Basin, The Nature Conservancy has directly protected more than 83,000 acres, contributing to a combined 310,000 acres privately and publicly protected in the region.

Significance for habitat/biodiversity: Like beavers, American alligators help reshape the wetland habitat in which they live. Instead of building dams, though, alligators dig large holes for dens. These holes then become habitat for other plants and wildlife when the alligator leaves.

Reviewed by Eric Krueger, Director of Science and Stewardship for TNC in South Carolina.

Photo Credit:  Michael Fuhr/TNC

Gray bat, Myotis grisescens

The gray bat is a medium-sized insectivorous bat with an overall length of about 3.5 inches and a wingspan of 10 to 11 inches. The gray bat occurs in limestone karst areas, meaning a landscape marked by caves, sinkholes, springs and other features, of the southeastern and midwestern United States. The gray bat was added to the U.S. list of endangered and threatened wildlife and plants in 1976.

Gray bats are known to live in caves, but recent data shows us that they will roost in culverts, dams, bridges, etc. There is at least one colony in a mine in MO.

Range: Alabama, Arkansas, Georgia, Illinois, Indiana, Kansas, Kentucky, Mississippi, Missouri, North Carolina, Oklahoma, Ohio, Tennessee, Virginia, West Virginia

Where to see: Nickajack Cave Wildlife Refuge—Maple View Public Use Area

Conservation approach: TNC’s conservation efforts have involved: • Purchasing restoring, and protecting caves that harbor federally endangered gray bats; • Limiting human access to caves by installing bat-friendly gates to prevent trespassing; and • Conducting research to help scientists understand the entire gray bat life history and behavior to inform conservation strategies.

Significance for habitat/biodiversity: During their pregnancy and nursing periods, gray bats consume nearly their own weight nightly in insects. Gray bats deposit some of that energy in the form of guano inside their cave homes, creating a rich environment for life to grow in a habitat with no sunlight or plants.

Learn more: Popular Science: Inside the World’s First Manmade Batcave Built For Wild Bats U.S. Fish & Wildlife Service Gray Bat Species Profile Tennessee Wildlife Resources Agency: Gray Bat Page

Reviewed by Cory Holliday, TNC’s Cave and Karst Program Director in Tennessee.

Attwater’s prairie chicken

Tympanuchus cupido attwateri

This small grouse is a highly endangered subspecies of the greater prairie chicken, native to Texas’ coastal prairies. Males have large orange air sacs on the sides of their necks, which they inflate during mating season to make a loud "booming” sound.

Range: Historically, the coastal prairies of Texas and Louisiana. Today, only two wild populations exist, both in Texas along the mid and upper Gulf Coast.

Where to see: Wild populations can be found at TNC’s Refugio-Goliad Prairie Project in Goliad County, Texas and the U.S. Fish and Wildlife Service’s Attwater Prairie Chicken National Wildlife Refuge in Colorado County, Texas.

Conservation approach: By 1996, habitat loss and development put wild populations of the Attwater’s prairie chicken at fewer than 50 birds. Collaborating with local landowners, conservation organizations and federal and state agency partners, TNC is using sustainable land management and stewardship practices to revitalize and protect prairie chicken habitat. Tools such as rotational grazing, prescribed burns and the removal of invasive species have helped restore the native landscape, creating healthy and resilient grasslands to support the species. TNC has also facilitated the release of over 1,000 captive-reared Attwater’s prairie chickens on private lands in Goliad County. Wild populations reached a 28 year high in 2021, demonstrating that captive-reared birds can successfully reproduce in the wild—a key strategy in reestablishing this critically endangered species.

Significance for habitat/biodiversity: The iconic Attwater’s prairie chicken is an indicator species for Texas coastal prairies and marshes; when these prairie chickens can’t make a living on the land, we know that the broader prairie habitat isn’t functioning properly. Ultimately, this reduced functionality impacts all of the other systems that depend on the integrity of our grasslands to thrive—our bays and waterways, our heritage farming and livestock industries and all of the people, plants and wildlife they sustain.

Learn more: Song of the Prairie: Restoring a Home on the Range for the Attwater’s Prairie Chicken U.S. Fish and Wildlife Service species profile

Reviewed by Kirk Feuerbacher, TNC’s Working Lands Program Director in Texas.

Photo Credit:  GaryKramer.net

Eelgrass, Zostera marina

Rising from shallow bay bottoms, ribbon-like eelgrass leaves may grow to 4 feet, often long enough to float on the surface. Forming vast underwater meadows, eelgrass provides food for waterfowl and green sea turtles; shelter for marine animals such as bay scallops, molting blue crabs, and juvenile fishes; and hunting grounds for gamefish such as striped bass.

Range: Atlantic coast from North Carolina to Labrador, Canada; Pacific coast from Baja California, Mexico, to Alaska; Mediterranean and Black seas.

Where to see: Eelgrass grows in shallow waters of the Chesapeake Bay and coastal bays along the seaside of Virginia’s Eastern Shore, where TNC’s Volgenau Virginia Coast Reserve hosts opportunities for volunteers to help restore this foundational marine habitat.

Conservation approach: Eelgrass virtually disappeared from Virginia’s coastal bays in the 1930s because of disease and a hurricane. But following the discovery of a small patch in a seaside bay off the Eastern Shore, TNC and the Virginia Institute of Marine Science used that seed source to launch restoration efforts. Since 2008, volunteers have helped collect millions of seeds, and eelgrass has regenerated across some 10,000 acres in four bays—the largest seagrass restoration project in the world.

Significance for habitat/biodiversity: Every 30 minutes, the world loses a football-field-sized area of seagrass meadows. From bay scallops to blue crabs and from seahorses to striped bass, myriad marine animals and waterfowl rely on these habitats for food and shelter. Moreover, research shows that seagrass habitats can play a vital role in bolstering coastal resilience and mitigating climate change.

Learn more: How You Can Help: Volunteer to Help Restore Eelgrass Photo Essay: Restoring Eelgrass on Virginia’s Eastern Shore Seagrass Stories: Barrier Islands Gose Brewed with Eelgrass

Reviewed by Bo Lusk , Coastal Scientist, TNC’s Volgenau Virginia Coast Reserve.

Photo Credit:  Jay Fleming

West Virginia

West Virginia northern flying squirrel

Glaucomys sabrinus fuscus

This small flying squirrel weighs a mere 4-6.5 ounces (about as much as a baseball) and is usually less than 1 foot long. Its large eyes aid its nocturnal nature. Mainly nesting in tree cavities, this flying squirrel usually has one litter of two to four young between March and May. Its preferred habitat includes forests with red spruce and old-growth characteristics.

Range: The range is from the Allegheny Mountains from Grant County, WV, southwest to Greenbrier County, WV, and Highland County, VA. Occurs at elevations above 3,300 feet. The Monongahela National Forest contains more than 90% of the known habitat within its range. A small amount of habitat is in Virginia’s Allegheny Mountain on the George Washington/Jefferson National Forest. The rest of the squirrel’s habitat is located on non-Federal lands.

Where to see: Mount Porte Crayon Preserve , Slaty Mountain Preserve , Monongahela National Forest, Blackwater Falls State Park, Canaan Valley National Wildlife Refuge, Canaan Valley State Park, Kumbrabow State Forest.

Conservation approach: Through collaboration of partners in the Central Appalachian Spruce Restoration Initiative (CASRI), the habitat for West Virginia northern flying squirrels have improved, which eventually led to the animal being removed from the U.S. endangered species list. Aiding the flying squirrel’s habitat the initiative has planted nearly 2 million spruce and other species, along with forestry activities to encourage spruce in appropriate areas, and the designation of spruce restoration in the 2004 Monongahela National Forest Land and Resource Management Plan. Additionally, TNC has acquired strategic tracts of land and conservation easements that connect, expand, and enhance the habitat required by flying squirrels.

TNC has identified and focused conservation efforts on several major landscapes and red spruce forests, including the Cheat Mountain Conservation Area, the Canaan Valley/Dolly Sods, Spruce Knob, and the Cranberry Conservation Areas. In addition, TNC has placed restoration and conservation measures by purchasing 57,000 acres of mineral rights on Cheat Mountain and more than 4,000 acres of surface rights in high elevation red spruce/northern hardwood forests transferred to the Monongahela National Forest.

Significance for habitat/biodiversity: West Virginia northern flying squirrel are an indicator species of high-quality red spruce and red spruce northern habitats along the high Alleghenies in West Virginia and a small portion of Virginia. The squirrel has a symbiotic relationship with truffles that grow underground in that they are the only known animal that disperses their spores. The red spruce forests of West Virginia contain approximately 240 species that the WV Division of Natural Resources tracks as rare, threatened, or endangered. These forests contain headwater streams that flow across the continental divide into both the Chesapeake Bay and Gulf of Mexico while providing flood attenuation and clean drinking water for millions downstream.

Reviewed by Mike Powell, West Virginia Director of Lands.

Photo Credit:  Patrick Cavan Brown

Questions About U.S. Conservation

Wildlife face many threats in the U.S. Many of these threats are the same facing wildlife in other parts of the world.

Here are some of the biggest threats facing biodiversity right now:

Climate change : Humans are feeling the impacts of climate change, and so is wildlife. Many species try to adapt by shifting their ranges: moving north and to higher elevation. But habitat fragmentation from human development makes movement more difficult. Some species can’t move because they’ve evolved within specific ecosystems, and they’re replaced with generalist species or driven to extinction. And some species, like ticks, are expanding their ranges and spreading diseases to new areas.

Climate change affects marine species as well as terrestrial species. Rising ocean temperatures threaten marine ecosystems like coral reefs, causing a loss of marine biodiversity and fisheries losses.

Habitat loss : There are many different types of habitat loss, each of which threaten wildlife. Some examples of habitat loss are deforestation, agriculture, mining and urbanization.

Habitat loss also includes degradation, such as from pollution, and fragmentation, such as roads through habitat or dams in streams.

Invasive species : Invasive species outcompete local and indigenous species for resources, causing declines in native biodiversity. Invasive species can also spread diseases that native species haven’t evolved to withstand and fuel devastating wildfires that destroy important wildlife habitat.

Pollution : Human activities cause a wide range of pollution in our environment, all of which threaten wildlife on land and in freshwater and marine ecosystems.

Here are just a few examples of pollution sources in the U.S.:

• Air pollution : We know that air pollution causes health problems in people, and it’s also damaging for wildlife. Burning fossil fuels is a main cause of air pollution in the U.S.
• Land pollution : Nitrogen pollution (often in the form of nutrient runoff from agriculture) has downstream effects on freshwater and marine wildlife, including dead zones and toxic algae. Pollution also comes in the form of plastic, industrial and household waste.
• Water pollution : Pollution often starts on land and ends up in water systems, harming freshwater and marine wildlife. Plastic and discarded fishing gear are two examples. Other pollution goes right into our waterways, such as waste from our modern sewage systems and stormwater pollution.

There are a variety of ways you can help wildlife near you and around the country! Here are just a few:

• Support conservation laws in your state and contact your elected officials
• Plant native plants : Turn your yard into a wildlife haven (and reduce your use of pesticides)
• Reduce your single-use plastic consumption : Plastic is a major pollutant of our oceans and risk to marine species
• Visit local preserves : Be sure to obey leash laws, stay on designated trails, and practice leave no trace
• Reduce the spread of invasive species : Clean your shoes and tires (and boats!) before and after traveling, buy local firewood, and ensure the plants you buy are not invasive
• Volunteer and attend events with The Nature Conservancy or other local conservation groups

The Endangered Species Act (ESA) is a U.S. law that creates protections for fish, wildlife and plants that are endangered or threatened with extinction. The ESA created guidelines for adding species to the list, removing species from the list, creating recovery plans, and funding conservation efforts. Its goal is to prevent extinction for species and their habitats.

The Endangered Species Act was passed in 1973 after many iconic species suffered declines. Since then, it has played a role in the comebacks of many iconic species.

The Endangered Species Act isn’t perfect, and threats to biodiversity remain enormously challenging. Many actions are needed to deliver the right policies, funding, and science, along with solutions for the tandem crisis of climate change.

The Recovering America’s Wildlife Act (RAWA) is a bipartisan bill that would help recover wildlife listed as threatened or endangered under the Endangered Species Act or state law, as well as preventing species from becoming endangered. RAWA will invest $1.397 billion per year in financial and technical assistance to state and Tribal efforts to help wildlife and local communities.

More than a third of America’s fish and wildlife species are at risk of extinction. States and Tribes have a long track record of success in helping recover species before they require the far more costly “emergency room” intervention of the Endangered Species Act. This conservation work also has multiple benefits for local communities, including job growth, cleaner water, and more outdoor recreation opportunities.

RAWA will fund on-the-ground conservation efforts of these species such as conserving and restoring habitats, fighting invasive species, reintroducing native species and tackling emerging diseases. Some of the funding will come from revenues from fees and fines for environmental requirement violations.

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How does the Endangered Species Act protect animals at risk?

From bald eagles to alligators, this historic conservation bill has helped save iconic American species from extinction for 50 years.

The United States’s Endangered Species Act (ESA), signed into law in 1973, has helped revive the populations of nearly 300 species .  

The ESA protects animals that are classified under federal law as “endangered”—at risk of going extinct—and “threatened”—at risk of being endangered.  

2023 marks the ESA’s 50th anniversary. In half a century, the law has created legal pathways for federal and local governments to work together to save species such as the bald eagle , the American alligator , the Florida manatee , and the peregrine falcon .  

Most recently,   the wolverine , a type of weasel, was added to the ESA because its existence is threatened by climate change and the loss of its habitat.

Here’s how the ESA works, and why conservationists say it’s more important than ever.  

How endangered species are protected

The U.S. Fish and Wildlife Service and the National Marine Fisheries Service are the two government agencies primarily responsible for implementing the ESA.  

To award a species ESA protection, these agencies take into consideration destruction to a species’ habitat, whether it has been over-consumed, threats from disease or predation, whether human actions put it in danger, and any policies currently protecting it.  

A federally protected species is typically listed with a “critical habitat” designation that outlines where ecosystems should be left untouched. The law also requires a research and management plan be formed to monitor a species’ population.  

It is illegal under the ESA to capture, hunt, shoot, or otherwise harm an animal that’s listed as endangered or threatened.

Conservation successes

Bald eagles are a poster child for the ESA and just one of the species to have seen tremendous population growth through conservation. In the 1960s, only about 500 bald eagles existed in the continental U.S. The birds ate fish infected with the pesticide DDT that was found in waterways. This chemical interfered with their ability to produce eggshells strong enough to hatch their young.

Captive breeding programs, habitat protection, and a ban on DDT helped restore bald eagle populations. Today, the U.S. Fish and Wildlife Service estimates more than 300,000 bald eagles live in the U.S.

The ESA also played a critical role in restoring populations of American alligators. After facing threats to their habitat and being excessively hunted, there only an estimated 100,000 individuals thought to exist across the South. Today, there are over a million, and the alligator was removed from the endangered species list in 1987.

Some species status on the endangered species list is unclear—as populations rebound, many are facing intensifying threats from habitat loss or climate change.

The whooping crane, North America’s tallest bird, can only be found in the U.S and Canada. It's thought 10,000 once existed in a habitat that spanned from the Great Plains to the Gulf Coast. In 1941, just 21 cranes were still alive. Today, the population is over 500 and listed as endangered, but scientists are debating whether it should be reclassified as threatened, a move that would loosen restrictions on habitats some scientists argue are increasingly at risk.

Conservation challenges

Critics have argued that the act is expensive and ineffective because it protects   over 1,300 species . Several federal courts have heard and rejected arguments that the ESA is unconstitutional. Members of Congress have tried to weaken the law, and spending cuts to federal agencies have limited how effectively scientists can monitor species’ health.

In October 2023, the U.S. Fish and Wildlife Service officially removed 21 species from the ESA, saying they were likely extinct. Many had been added to the endangered species list in 1973 and may have already been extinct at the time they were listed.  

One species, the ivory-billed woodpecker, was last seen in 1944 but remains a hotly debated scientific mystery. Initially considered for delisting, the bird remains on the list as scientists continue to debate its survival.  

The ESA remains critical for protecting endangered species. Studies show the rate of extinction is increasing around the world . Nearly a third of plants and 40 percent of animals in the U.S. are existentially threatened, according to research done by the environmental group NatureServe.

In a press release announcing the 21 presumed extinct species, the U.S. Fish and Wildlife Service highlighted the important role the ESA plays of protecting species "before declines become irreversible."  

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Related topics.

• ENDANGERED SPECIES
• BIODIVERSITY
• CLIMATE CHANGE
• HABITAT LOSS

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Research Progress on endangered plants: a bibliometric analysis

• Review Paper
• Published: 07 March 2022
• Volume 31 , pages 1125–1147, ( 2022 )

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• Jie Xu 1 , 3 ,
• Pengnan Xiao 2 ,
• TingTing Li 1 , 3 &
• Zhengxiang Wang   ORCID: orcid.org/0000-0001-9514-6712 1 , 3  

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The rapid extinction of endangered plants (EPs) may lead to the destruction of entire ecosystems, which will seriously threaten the survival and development of humans. Research on endangered plants should be strengthened to scientifically guide the protection of endangered plants. Based on 1635 publications collected from the Web of Science Core Collection ™ (WoS), this paper aims to provide a comprehensive bibliometric run-through and visualization of the subject of EPs. Contingent on influential authors, organizations, top journals and subject category, as well as the most influential papers in the EPs field were discussed in detail. Afterwards, by analyzing the co-occurrence network and evolution path of keywords, to discover the main research topics. In the discussion part, this paper focuses on important issues and research frameworks in the field. The main motive of the paper is to assist research workers interested in the area of EPs to determine the ongoing potential research opportunities and hotspots.

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This research was funded by the National Natural Science Foundation of China (42101065), the Central Government Guides Local Science and Technology Development Projects(2019ZYYD050), the Open Foundation of Regional Development and Environmental Response, Key Laboratory of Hubei Province (2021(C)002.)

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Jie Xu, TingTing Li & Zhengxiang Wang

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Conceptualization, ZX.W and J.X.; methodology, J.X and P.X.; software, P.X. and J.X and TT.L.; writing—original draft preparation, P.X. All authors have read and agreed to the published version of the manuscript.”

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Xu, J., Xiao, P., Li, T. et al. Research Progress on endangered plants: a bibliometric analysis. Biodivers Conserv 31 , 1125–1147 (2022). https://doi.org/10.1007/s10531-022-02392-y

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How to help protect endangered species

As you read this, countless species are on the brink of extinction. We live in an era where global biodiversity faces threats that are caused in large part by human actions.

But there are things we can do to help. Individuals committed to conservation can take collective action to protect endangered species from extinction. Here we explore some practical strategies that you can implement in your daily life to protect endangered wildlife.

16 things you can do to help endangered species

Conservation efforts don’t just have to be spearheaded by large organizations—individuals can make a difference, too. The choices we make in our day-to-day lives can have a positive impact on threatened species. 

Buy products from sustainable sources

Choosing cruelty-free alternatives helps reduce the demand for goods that contribute to the endangerment of species. Avoid buying products made from animal skins, scales, ivory, or other endangered animal products. 

Though it can seem like a personal choice that only affects you, you directly contribute to wildlife conservation by actively purchasing from sustainable sources. 

If enough people make these choices, businesses will be encouraged to adopt ethical practices and invest in more sustainable alternatives. 

Advocate for conservation

Using your voice to bring attention to the plight of endangered species educates others and builds support for conservation causes.

This can be as simple as talking to your friends and sharing resources or links on social media, along with attending events, signing petitions, and writing to elected officials.

Not sure where to start? We have a list of active petitions that you can sign to help ensure your voice is heard—from helping to save North Atlantic right whales from extinction to forming a national biodiversity strategy. 

Avoid plastic use and littering, and recycle properly

Ensuring that you properly dispose of waste and recyclables can play a huge part in protecting the environment and animal populations. Recycling plays a pivotal role in breaking the cycle of plastic pollution by diverting materials from landfills and ensuring that plastics don’t end up endangering wildlife through ingestion or entanglement.

Beyond proper recycling, try to use alternatives to plastic products (especially single-use plastics). Products like metal straws instead of plastic ones, beeswax wraps instead of cling film, and reusable water bottles can all make a difference. 

Learn more about wildlife and educate others 

Empower yourself through knowledge. By learning more about wildlife and endangered species —and then sharing that knowledge with others—you can create a ripple effect of awareness.

IFAW is all about educating, sharing knowledge, and promoting collective action. Our blog is a great place to start if you want to learn more about conservation and endangered species. Learn more about endangered wildlife in Africa , Europe , Asia , Australia , North America , and South America , or take a look at our list of the world’s most endangered mammals or birds .

Support conservation organizations 

Supporting conservation organizations is a great way to protect endangered species. Donations provide crucial funding for research, habitat protection, wildlife rescue, and species recovery programs.

If you’re not in a position to provide financial support, there are other ways you can support conservation efforts. Identify organizations dedicated to causes you to care about, follow them on social media, and reshare their posts. This helps to amplify their reach and spread awareness. You can also look for volunteering opportunities at conservation organisations and wildlife centres in your local community.

Through these actions, you can support the collective effort to safeguard endangered species. 

Support policy initiatives that help animals

One of the most effective ways to protect endangered species is through policies prioritizing animal welfare and conservation. Many animals are already protected by law, and the more we can introduce legislation to protect threatened species, the better.

You can stay informed about relevant legislation and advocate for stronger protections for endangered species. Or try engaging with your local elected officials by expressing concerns and providing input on wildlife-related policies. You can also join or support organizations lobbying for effective conservation policies. 

Protect wildlife habitats

Individuals play a crucial role in protecting endangered species by safeguarding their habitats. Simple actions can make a significant impact, for example: 

• Letting your lawn grow provides a haven for important pollinating insects and small animals. 
• Planting native trees (and not cutting down existing ones) helps restore natural ecosystems. 
• Setting up water sources in your yard or garden aids local wildlife, especially during dry periods. 
• Planting native flowers supports pollinators, which is essential for the reproductive success of many species. 

You should also refrain from disturbing wildlife in your community. If you see a wild animal that appears orphaned or distressed, contact your local wildlife rehabilitation center for help. 

Participate in park, roadside, or beach cleanups

Participating in park, roadside, or beach cleanups is a direct action that can help you contribute to the protection of endangered species. Have a look to see if there are any community- or council-led cleanups in your area. 

Removing litter and waste preserves natural ecosystems, prevents harm to wildlife, and raises public awareness about the impact of pollution on endangered species and their habitats.

Host a community fundraising event

Organizing events like charity walks, auctions, or educational seminars can raise funds for conservation efforts. These events not only generate financial support but also help spread the word about the importance of biodiversity and conservation. 

Your event’s funds can be given directly to conservation organizations to support their efforts to conserve biodiversity.

Volunteer with an animal shelter or sanctuary that rehabilitates wildlife

Volunteering at a shelter is a hands-on way to directly contribute to protecting endangered species. 

Find an organization near you dedicated to wildlife rescue and rehabilitation and inquire if they’re open to volunteers. By dedicating your time and skills to these organizations, you can help with the care of animals while also learning more about the cause. 

Use alternatives to pesticides

If you have a garden, avoid using pesticides on your plants and vegetables. Opting for natural and eco-friendly pest control methods helps maintain a balanced ecosystem without harming non-target species. Planting native vegetation that attracts natural predators can also reduce the need for chemical interventions.

For more information, you can speak with workers at your local garden center to find a solution that will protect your harvest without harming native wildlife around your home. 

Travel sustainably and support wildlife-friendly tourism

The next time you take a trip, avoid booking a package holiday and instead think a bit more deeply about ways you can travel sustainably to help reduce the negative impact of tourism on ecosystems.

This can include wildlife tourism, like safaris or whale watching, but make sure you look into tour operators that prioritize conservation and animal well-being.

Here are some ideas to make your trips more sustainable:

• Opt for eco-friendly accommodations and tour operators that prioritize conservation practices.
• Choose destinations with responsible wildlife tourism guidelines, ensuring minimal disturbance to natural habitats. 
• Participate in educational programs and eco-tours that raise awareness about endangered species and their conservation needs. 
• Respect local wildlife regulations, keeping a safe distance from animals in their natural habitats. 

Follow vessel speed rules on the ocean

If you’re a boat owner or driver, it’s essential to always follow vessel speed rules. This isn’t just for your safety—it also protects marine life below the surface. 

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Scientists trying to protect wildlife from extinction as climate change raises risk to species around the globe

By Grace Manthey , David Schechter , Tracy J. Wholf , Chance Horner , Haley Rush , Alexis Guerrero

Updated on: April 22, 2024 / 1:02 PM EDT / CBS News

From clean air and water to healthy soil and medicines, our survival and prosperity rely heavily on the rich diversity of plants and animals that make up our world. A 2019 U.N. report found that around 1 million plant and animal species could be threatened with extinction around the globe. But new  research finds climate change could drive up to 6 million different species to extinction over the next 50 years, including in communities across the United States.  

CBS News and Stations explored how a warming planet and unchecked development are leading to significant population declines in species, why that's bad for humanity, and the heroic lengths some scientists will go to protect life on Earth. 

For some species, it's already too late. For others, there are innovative ways to help rehabilitate a species decimated by climate change. Scientists are using a range of tools to protect species in creative and unique ways and to anticipate future changes.

In Bisbee, Arizona, one scientist who has spent his career studying evolutionary biology and ecology is tracking a 3-million-year-old lizard population dying at one of the fastest rates ever recorded. 

Another group is trying to save the Puerto Rican parrot , one of the most critically endangered birds in the world, as more destructive hurricanes jeopardize the parrot's ecosystem.

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Endangered species by the numbers 

The U.S. Endangered Species Act was established in 1973 and provides federal protection for wildlife in danger of becoming extinct.

The main agency responsible for carrying out the act, the U.S. Fish and Wildlife Service, lists  nearly 1,700 species endangered or threatened as of April 1. Nearly 1,400 species  on the list have active recovery plans. New species are added every year. 

A 2019 study estimated the Endangered Species Act had prevented the extinction of nearly 300 species since its passage. 

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Number of endangered or threatened species by county in the U.S.

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Across all U.S. states, Hawaii has the greatest number of species listed as endangered or threatened by the U.S. Fish and Wildlife Service —  estimated at nearly 500 species.  

Endangered or threatened species in Hawaii

The number is driven mostly by flowering plants, including the iconic state flower, the ma'o hau hele, or native yellow hibiscus flower. 

California has the second highest number listed, with nearly 300 endangered or threatened species. This includes the San Joaquin kit fox and the Lange's metalmark butterfly. Like Hawaii, the high number is driven by the roughly 170 species of flowering plants. There are higher numbers in coastal, central and southern counties.

Number of endangered threatened species by county in California

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• Published: 24 April 2024

Opening the black box: explainable deep-learning classification of wood microscopic image of endangered tree species

• Chang Zheng 1 , 2 ,
• Shoujia Liu 1 , 2 ,
• Jiajun Wang 1 , 2 , 4 ,
• Yang Lu 1 , 2 ,
• Lingyu Ma 1 , 2 ,
• Lichao Jiao 1 , 2 ,
• Juan Guo 1 , 2 ,
• Yafang Yin 1 , 2 &
• Tuo He 1 , 2 , 3  

Plant Methods volume  20 , Article number:  56 ( 2024 ) Cite this article

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Traditional method of wood species identification involves the use of hand lens by wood anatomists, which is a time-consuming method that usually identifies only at the genetic level. Computer vision method can achieve "species" level identification but cannot provide an explanation on what features are used for the identification. Thus, in this study, we used computer vision methods coupled with deep learning to reveal interspecific differences between closely related tree species.

A total of 850 images were collected from the cross and tangential sections of 15 wood species. These images were used to construct a deep-learning model to discriminate wood species, and a classification accuracy of 99.3% was obtained. The key features between species in machine identification were targeted by feature visualization methods, mainly the axial parenchyma arrangements and vessel in cross section and the wood ray in tangential section. Moreover, the degree of importance of the vessels of different tree species in the cross-section images was determined by the manual feature labeling method. The results showed that vessels play an important role in the identification of Dalbergia , Pterocarpus , Swartzia , Carapa , and Cedrela , but exhibited limited resolutions on discriminating Swietenia species.

The research results provide a computer-assisted tool for identifying endangered tree species in laboratory scenarios, which can be used to combat illegal logging and related trade and contribute to the implementation of CITES convention and the conservation of global biodiversity.

Illegal logging is the most profitable natural resource crime over the world. The financial value of illegal logging and related trade is approximately $52 to $157 billion per year [ 1 ]. Therefore, the international community has emphasized the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) to ban or restrict trade in endangered tree species to combat illegal logging and related trade [ 2 , 3 , 4 , 5 , 6 ]. As of 2023, approximately 670 tree species have been listed in CITES Appendices because of their overexploitation. The main barrier to the implementation of CITES is the definitive identification of traded timber and wood products, where forensic tools are urgently required [ 3 , 7 ].

In the Neotropics (South and Central America and tropical Mexico), three commercially important species of Swietenia (Meliaceae) are listed in CITES Appendix II [ 8 ]. The wood of these three species are widely considered indistinguishable by wood anatomists [ 9 , 10 ]. Dalbergia and Pterocarpus are two other important genera of Leguminosae, often referred to as rosewood tree species [ 11 ], and most species from these genera are threatened by illegal logging activities.

All Dalbergia species (except D. nigra which is listed in Appendix I) are listed in Appendix II, and for Pterocarpus spp., P. santalinus , P. erinaceus , P. tinctorius as well as Pterocarpus species that are from an African population are also listed in CITES Appendix II. These woods are used for furniture, musical instruments, and handcrafts because of their beauty, workability, and moderate resistance to corrosion, and are highly sought after by consumers worldwide [ 12 , 13 ]. In the international trade of CITES-listed tree species, documents with fake names of similar species are often submitted to customs officials to avoid inspection. Consequently, the discrimination of CITES-listed tree species from their look-alikes is a key step in combating the illegal timber trade.

Wood anatomy is one of the most important methods for field wood identification [ 10 , 14 , 15 ], and is performed by observing various anatomical features using a hand lens in three orthogonal directions, i.e., cross, radial, and tangential [ 16 ]. However, wood identification is a difficult task that requires specialized anatomical knowledge and a wide range of interspecies and intraspecies similarities [ 17 ]. This results in professional wood anatomists often requiring decades of specialized training to achieve genus-level identification. In contrast, computer vision can provide an economical alternative to human-based biological domain support for in situ screening of wood in trade, which is faster, does not require individual skill training and can yield species-level identification if sufficient images covering intraspecific variation are available for model training.

Currently, computer vision is developing rapidly, and there has been a lot of work done in wood macro image classification [ 18 , 19 , 20 ]. In forensic wood identification, it is often necessary to provide identification keys, namely the features on which experts base their judgments. However, the deep-learning model is like a black box, which cannot provide the basis of judgment in classification as a wood anatomist can. Although many studies have demonstrated that wood anatomy images coupled with deep learning can discriminate between wood species and their look-alikes at the species level, the diagnostic features extracted by this model remain invisible. In the context of wood identification, wood anatomists are not only interested in what the species is, but also want to know what anatomical features can accurately and efficiently discriminate this species from their look-alikes.

Existing research has shown that vessel is the key feature for wood identification [ 19 ]. With the help of feature visualization, it can explore whether the key features recognized by intelligence methods are consistent with wood anatomists. Meanwhile, it is possible to explore the inherent features in wood species to determine the differences in wood anatomical features between similar species [ 21 , 22 ]. Feature visualization will help wood anatomists to be more effective when conducting wood identification tasks in the field [ 19 ].

As two commonly used methods in computer vision, machine learning and deep learning have different workflows. Machine learning-based wood identification is an information-driven research field in which many researchers understand wood identification from a new perspective based on the knowledge of wood science. Machine learning methods require researchers to assemble a dataset by gathering wood anatomical, chemical, or genetic information and then analyze it using unsupervised or supervised models [ 23 , 24 ]. This information can be collected in the form of images, videos, text, and measurements. Deep learning models can make use of image data to a greater extent over other types of data. Although deep-learning models can accurately identify wood species, interspecific differences in morphological features still need to be determined.

The purpose of this study was to reveal interspecific differences between similar tree species using computer vision methods. First, a dataset of slide images in the cross and tangential sections of 15 similar tree species was created and a deep-learning model was established. Feature visualization was then conducted to target the key differences between species in the image classification. Then, the degree of importance of the vessels in the cross sections of different wood species was determined using the manual feature labeling method. The model developed in this study provides a tool that can identify wood species quickly and visualize important features that can help anatomists complete identification work more accurately and support effective CITES implementation.

Materials and methods

Data preparation.

Fifteen species from Carapa , Cedrela , Dalbergia , Swartzia , Pterocarpus, and Swietenia were selected for this study and divided into four groups based on their anatomical similarity (Table  1 ). Multiple wood specimens of the selected species were collected for sectioning [ 25 ] and 2–3 images of the cross-or tangential sections of the heartwood were collected for each specimen. Images of 4096 × 2160 pixels and 8-bit RGB in PNG format, representing 2.23 × 0.78 mm of tissue, were captured using a microscope at 5 × magnifications.

A total of 50–60 images per species were captured to cover the variability of the tree species as much as possible and ensure data balance for each species. Details of data collection for the selected tree species are listed in Table  1 and their anatomical features of each group are presented in Additional file 1 : Table S1. The images of Carapa guianensis , D. latifolia, and P. indicus were captured at both 2.5 × and 5 × magnifications to verify whether the visualization results were altered with image magnifications.

Image dataset construction and processing

Putting the original image of 4096 × 2160 pixels directly into the CNN model increases the burden of model training; thus, the patch sizes of 600 × 600, 800 × 800, 1000 × 1000, 1200 × 1200, 1400 × 1400, 1600 × 1600, 1800 × 1800, and 2000 × 2000 pixels were extracted from the original image to increase the size of the dataset [ 19 ], and a 20% repetition rate was left when the patches are extracted to ensure feature integrity. The extracted patches were divided into training and testing sets in a ratio of 8:2 and then fed into the deep-learning model ResNet152 for training, and the optimal test results were obtained after tuning the parameters. In terms of parameter tuning, the parameters such as learning rate, learning rate update strategy, image enhancement method, and maximum number of iterations were modified.

Vessel dataset introduction and processing

The classification of individual features of wood microscopic images by manual annotation is typically performed using an object-detection model that contains backbone networks, neck networks, detection heads or other components, such as YOLO (You Only Look Once) [ 26 ], SSD (Single Shot MultiBox Detector) [ 27 ] and Faster R-CNN (Region Convolution Neural Network) [ 28 ]. The network structure of Faster R-CNN is shown in Fig.  1 .

Faster R-CNN network model diagram, consisting of backbone and RPN network

To test the effect of the vessel on the accuracy of the trained model, it is necessary to ensure that the original variables are fixed, and only the vessel features of wood are input. Object detection was performed mainly by building a ResNet152 (consistent with the wood classification model), with the addition of a neck network and the inclusion of a detection head (e.g., YOLO Head) used to regress the bounding box. In the regression of the bounding box, although the same backbone network (ResNet152) was used for object detection, a neck network such as the detection head (or RPN) would affect the detection results, which could not result in the quantitative analysis.

The labeling tool LabelImg [ 29 ] was used to label vessels in the images, to eliminate the influence of, for example, the neck network and the detection head. In the vessel dataset, the labeled vessels were directly cropped by means of image cropping to create a new image, which eventually composed a dataset of vessels of different tree species, and then, the same neural network model was used to train and test the vessel dataset to obtain the final classification results. Thus, the process was simpler, and no remodeling was required. The classification was more accurate and the influence of other network structures on the result eliminated, which fundamentally solved the problem of incorrect detection.

The vessel dataset contained vessels from cross-sectional images of the 15 tree species, and the details of the vessel dataset are shown in Additional file 2 : Table S2. To balance the data, the dataset was processed before training, and for tree species with more vessel features, such as Carapa guianensis (455 vessel features) and Swartzia madagascar (798 vessel features), excessively duplicated vessels were removed. In addition, incomplete feature shots were inevitably present in the original images. Therefore, vessels with fewer than 50% missing areas were selected for retention.

ResNet152 model architecture

Research has shown that in deep-learning models, the deeper the network layer, the higher the accuracy of the model. ResNet [ 30 ] is currently one of the best-performing neural networks for image classification tasks. The ResNet network structure mainly refers to VGG19 and adds residual units on top, which solves the degradation problem that occurs with the deepening of the network models. ResNet152 was used for training and testing, thereby laying the foundation for feature visualization. The network structure of ResNet152 is shown in Fig.  2 .

ResNet Network Model Diagram

The residual units consist of three convolutional kernels (1 × 1, 3 × 3, and 1 × 1) and a jump connection, which can be expressed as Formula 1 :

where \(x_l\) and \(x_{l + 1}\) are the input and output of the lth residual unit, respectively, and each residual unit contains a multilayer structure, as shown in Fig.  2 . \(F\) represents the residual network, \(h(x_l ) = x_l\) is the identity mapping, and \(f\) is the ReLU (Rectified Linear Unit) activation function, which can be represented by Formula 3 , where \(x\) represents the input data.

Training and prediction

The deep-learning model was trained using the training set and tested at each epoch using the test set. All patches were adjusted to 224 × 224 pixels for a total of 3 channels, and the average value of each channel was calculated from the entire image in the two datasets. A total of 400 patches were input into the model for each iteration and subtracted from the mean. Then, the model is optimized using stochastic gradient descent (SGD) algorithm to control overfitting, and the model was iterated through 100 cycles with an initial learning rate of 0.225 and momentum of 0.9. A fixed-step decay was used, and the learning rates decayed to 0.0225 and 0.00225 when the number of iterations was 30 and 60, respectively.

• Feature visualization

In the CNN model, the class activation map (CAM) shows discriminative image regions that help in classification [ 31 , 32 , 33 ]. The last convolutional layer of the neural network contains the richest spatial and semantic information; therefore, the CAM makes full use of the last convolutional layer features and replaces the later fully connected and softmax layers with a global average pooling (GAP) layer, replacing the values of the entire feature map with the mean values of all pixels. Each feature map has a corresponding weight, and the weighted sum of the globally averaged pooled feature map provides the class activation thermodynamic diagram of the corresponding category and corresponding prediction scores.

Influence of different multiples

Previous studies trained microscopic images of the three sections and then identified the test images [ 1 , 34 ]. Here, we explored the impact of different multiples on identification results and feature visualization. This experiment selected the cross-sections of three species, Carapa guianensis , D. latifolia, and P. indicus with 2.5 × and 5 × images in the dataset to discuss the relationship between shooting magnification and visualization results. These three tree species were selected because images of different magnifications were collected under the same experimental conditions, enabling comparative analyses to be conducted. Both datasets were cropped to 800 × 800 simultaneously. The overlap rate of each block patch was approximately 20%. Owing to the small number of training categories, the final accuracy was 100% after 100 iterations for the ResNet152 model.

Results and discussion

Identification results of resnet152 and the accuracy against the patch size.

Before training, different patch sizes were first extracted at a repetition rate of 20%, and the tree species were recognized using ResNet152. The accuracy is shown in Fig.  3 . The highest classification accuracy (0.9932) was achieved with a patch size of 800 × 800 pixels. Although the ResNet152 classification accuracy was highest among the results, the 800 × 800 pixel patch size was too small to cover all the wood anatomical features. Therefore, the model was trained with a larger 1800 × 1800 pixel patch size for the feature visualization experiments. The results of four closely related species, P. indicus , P. macrocarpus , P. soyauxii, and P. tinctorius were selected for discussion.

The classification accuracy against different patch sizes

This result demonstrates that ResNet152 can accurately identify the selected tree species in the dataset. In existing study, CNN was used to identify cross-section microscopic images of 112 tree species, and the overall accuracy reached 95.6% [ 34 ]. Our study showed a relatively higher accuracy despite the difference of the image datasets and models deployed.

The confusion matrix of the classification results when using the 800 × 800 patches are shown in Fig.  4 . The number of misidentified patches of these species was less than one except for Swietenia mahagoni , Swietenia humilis, and Swietenia macrophylla. Three patches of Swietenia humilis were misidentified as Swietenia macrophylla . Two patches of Swietenia macrophylla were misidentified as Swietenia mahagoni and two patches were misidentified as Swietenia humilis . Only two patches of Swietenia mahagoni were misidentified as Swietenia macrophylla . Overall, the number of erroneous patch sizes in the test set was 17 with a classification accuracy of 99.32%.

Classification result confusion matrix

Only two Dalbergia images were incorrectly identified in the confusion matrix of the classification results. Simultaneously, within the Pterocarpus genus, species exhibit similar characteristics. P. tinctorius and P. soyauxii are listed in CITES Appendix, while the other two species are not listed in CITES Appendix. Therefore, obtaining more accurate identification results is necessary to combat illegal logging. Only two cases of images of Pterocarpus were identified incorrectly in the classification results. And one case of CITIES-listed P. soyauxii was incorrectly identified as non-CITES P. macrocarpus .

The features of the macroscopic images were significantly similar, thus, it is difficult for deep-learning models to determine the differences between the features of different species. By contrast, the features of the microscopic images were finer, and the differences between tree species can be represented by pixels. As a result, deep-learning models can easily reach correct identifications. Although differences can be identified through traditional wood anatomy, deep-learning methods are automatic and timesaving.

Identifying similar features using quantitative wood anatomy data coupled with machine learning analysis has become a common method, making it easier to distinguish key features among species. However, current studies have only focused on improving accuracy and has not been able to explain the specific features used for classification [ 34 ]. This study demonstrates that the combination of deep learning with microscopic images yields better performance [ 14 , 35 ] and further provides the explanation deep-learning classification results by feature visualization.

Although the classification accuracy of the patch size of 800 × 800 pixels was the highest among the classification results of ResNet152, considering that the patch size of 800 × 800 pixels was too small to cover all wood anatomical features, the model trained with a patch size of 1800 × 1800 pixels was selected for the feature visualization experiments. The results of four closely related species, namely P. indicus , P. macrocarpus , P. soyauxii, and P. tinctorius were selected for discussion. The results are shown in Fig.  5 .

Feature visualization results of Pterocarpus. A , B P. indicus in tangential section and cross section; C , D P. macrocarpus in tangential section and cross section; E , F P. soyauxii in tangential section and cross section; G , H P. tinctorius in tangential section and cross section. The yellow circles represent vessels that were not activated by the model. The red dashed circles represent axial parenchyma near the vessels were activated by the model. The white circle represents wood ray in tangential section were actvated by the model

P. indicus and P. macrocarpus have similar anatomical features; specifically, the vessel diameter of P. indicus is always larger than P. macrocarpus [ 36 ]. According to Insidewood [ 37 ], the axial parenchyma arrangements of all Pterocarpus species are aliform banded and terminal. The ray widths and heights of P. indicus and P. macrocarpus showed few differences, compared with those of P. soyauxii and P. tinctorius . The wood rays of P. indicus and P. macrocarpus can be considered similar to those of P. soyauxii and P. tinctorius. Both groups can be classified based on the width and height of the wood rays [ 15 ].

As shown in Fig.  5 , the key features of the four species of P. indicus , P. macrocarpus , P. soyauxii, and P. tinctorius are shown in the cross section as axial parenchyma arrangements near the vessel and in the tangential section as the distribution of wood rays. This indicates that the results of feature visualization were consistent with the results of traditional wood anatomy. Some key features are lost during model training as the input images undergo a down-sampling process. The classifier did not visualize all features, including the vessels, axial parenchyma, and wood rays, which may affect the feature results.

Visualization results for different multiples

Although our previous study conduct feature visualization of deep learning models with macroscopic images of Dalbergia and Ptercarpus species, images from different multiples were not tested, which is especially important for microscopic images [ 19 ]. The visualization results for Carapa guianensis (Fig.  6 ), showed different multiples had no effect on activated features, specifically for the axial parenchyma arrangements near the vessels. The computer considered the arrangement of the axial parenchyma as the main factor for identification, with vessels also having some influence on the identification results. Based on this result, we consider that using 5 × images are much better because they can balance the number of images with the field of view and ensure the integrity of the organizational features within the image.

Visualization Results of Carapa guianensis , D. latifolia and P. indicus at different multiples. A Carapa guianensis at 2.5 × ; B Carapa guianensis at 5 × ; C D. latifolia at 2.5 × ; D D. latifolia at 5 × ; E P. indicus at 2.5 × ; F P. indicus at 5 × . The yellow circles represent vessels that were not activated by the model. The red dashed circles represent axial parenchyma near the vessels were activated by the model

Identification results of the vessel dataset

As shown in Fig.  7 , the vessel dataset was modeled, the performance of the network was evaluated, and the final confusion matrix was obtained with an average precision of 83.15% for each tree species. Only Carapa guianensis and Swartzia madagascar had higher classification accuracies of 94.51% and 97.48%, respectively, indicating that the model could identify these species only by vessels. This suggests that vessel features have a greater influence on species identification.

Confusion matrix diagram of vessel dataset. The different color boxes represent tree species that belong to Group 1–4

In contrast, the classification accuracies of Swietenia humilis , Swietenia macrophylla , and Swietenia mahagoni were 64.13%, 68.48%, and 72.88%, respectively, indicating the relatively small influence of vessels. Interestingly, the vessels of all three Swietenia species were similar. Although it had low classification accuracy, none of the Swietenia species were identified as Pterocarpus , Dalbergia , Cedrela , Carapa, or Swartzia, and the differences among these three species were small. It also confirms the conclusion that “the wood of the Swietenia species cannot be separated anatomically with any degree of certainty” [ 38 ]. For similar species of Carapa guianensis and Cedrela odorata , only two cases of test examples existed in the dataset, where Cedrela odorata was incorrectly identified as Carapa guianensis , and for these species, the model could differentiate based on the vessels.

Among the four species of Dalbergia , the classification accuracies for D. latifolia and D. stevensonii were lower (73.47% and 66.67%, respectively). However, within the same genus, there were fewer misidentifications, with only D. latifolia and D. stevensonii being more easily misidentified. This indicates that the vessels are one of the main identification features of Dalbergia . This result is consistent with “main wood anatomical features activated by the model for Dalbergia species were mainly vessel groupings” [ 18 ].

Among the four species of Pterocarpus , the classification accuracy of the vessel data was relatively high compared to that of Dalbergia , all of which were greater than 80%. However, there were few misidentifications among these four species. This indicates that vessels are one of the main features of Pterocarpus, which is consistent with “the deep-learning model was more sensitive to the axial parenchyma arrangement than to the vessel groupings and other anatomical features” [ 19 ].

Except for the three Swietenia species, Dalbergia latifolia , and Dalbergia stevensonii , the accuracy of vessel classification for the remaining 10 species ranged from 83.76 to 97.48%, and only a few examples of misidentified species, indicating that for these 10 species, vessel features had a greater influence on wood identification but could not be used as a final basis for discrimination.

Traditional in situ screening of wood species relies on wood anatomists using hand lenses, which is a time-consuming method that usually identifies only to the genus level, whereas existing intelligent classification methods fail to provide a basis for judgments. In this study, we developed a deep-learning model to identify microscopic images of similar tree species and screen the key features among these species. Images of 15 species were collected from the cross and tangential sections of wood specimens, and the ResNet152 model trained on the images achieved a classification accuracy of 99.3%, indicating a more accurate overall performance than that of wood anatomists. The key features between species were targeted by class activation maps, and the results showed that the key features were axial parenchyma arrangements near the vessel in the cross-sectional images, and the distribution of wood rays was shown in the tangential section. In species identification, it has been proven that different magnifications do not affect species identification or visualization. Moreover, the degree of importance of vessel features in cross-sectional images for different species in depth model identification was determined, and the results showed that vessels were among the main features of Dalbergia, Pterocarpus , Swartzia , Carapa, and Cedrela . The research results provide a computer-assisted tool for identifying endangered tree species and present visible identification results for judgment, which can be used to combat illegal logging and related trade and contribute to the implementation of CITES regulations and the conservation of global biodiversity.

Availability of data and materials

The scripts used for classification in this study are available on Github: https://github.com/zhengchang01/woodslice-classification-based-ResNet152/tree/master .

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Acknowledgements

We would like to thank Alex C. Wiedenhoeft of Center for Wood Anatomy Research, USDA Forest Service, Forest Products Laboratory for his help with data support.

Project of Natural Science Foundation of China, 32201496.

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Chang Zheng, Shoujia Liu, Jiajun Wang, Yang Lu, Lingyu Ma, Lichao Jiao, Juan Guo, Yafang Yin & Tuo He

Wood Collections, Chinese Academy of Forestry, Beijing, 100091, China

Wildlife Conservation Monitoring Center, National Forestry and Grassland Administration, Beijing, 100714, China

National Centre for Archaeology, Beijing, 100013, China

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TH, YL and JW prepared the samples for imaging and imaged the specimens. TH curated the collected dataset. CZ developed the deep learning models. CZ, TH, YL and SL designed the experiments. TH, CZ, YL, LJ, JG, LM and YY, analyzed the results and wrote the paper. All authors read and approved the final manuscript.

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Additional file 1..

Microscopic anatomically features for selected species showing their similarity of each group.

Additional file 2.

The detailed information of selected species in this study.

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Zheng, C., Liu, S., Wang, J. et al. Opening the black box: explainable deep-learning classification of wood microscopic image of endangered tree species. Plant Methods 20 , 56 (2024). https://doi.org/10.1186/s13007-024-01191-6

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Missing link in species conservation: Pharmacists, chemists could turn tide on plant, animal extinction

• Kim North Shine

As the world faces the loss of a staggering number of species of animals and plants to endangerment and extinction, one University of Michigan scientist has an urgent message: Chemists and pharmacists should be key players in species conservation efforts.

“Medicinal chemistry expertise is desperately needed on the frontlines of extinction,” said Timothy Cernak , assistant professor of medicinal chemistry at the U-M College of Pharmacy. “Animals are dying at staggering rates, but they don’t have to. Modern bioscience has achieved enormous breakthroughs in treating disease in humans, and the same medications, and the science behind them, can be applied in the wild.”

Local and global efforts to reduce environmental damage are underway, but they are too slow to save the many ailing populations in the wild, he said.

“We are in the middle of a mass extinction. We are chasing mass die-offs around the world. Lowland gorillas, Argentinian penguins, the akikiki bird in Hawaii, loggerhead turtles in Florida. The list goes on, and many precious plants are also hanging by a thread,” he said. “So it’s critical to bring the power of modern pharmaceuticals and the dosing expertise of medicinal chemistry into conservation efforts.”

Cernak and a team of young scientists, including a local high school student, make the case for establishing and nurturing the emerging field of conservation medicine in a research article published this week in the Journal of Medicinal Chemistry.

“It’s hard-core science. It’s bringing the lens of medicinal chemistry and modern pharmaceuticals into the conversation to save other species,” Cernak said. “Drivers of the current mass extinction include habitat loss, global warming and overharvesting, but one specific root cause—wildlife disease—seems ripe for intervention. Medicinal chemistry is that intervention.”

Cernak, in one of many roles and research projects, receives samples of dead and ailing species from around the world. Using the same methods and models used to find compounds that work against human disease, his lab at U-M, which recently brought a veterinarian on board, tests chemical compounds on samples to see which ones respond to disease-causing organisms. A major focus is fungus, the single-largest killer of amphibians.

In their paper, the authors propose a new role for chemistry and pharmacy on the frontlines of preventing extinction: “A long-term solution to mass extinction is to fix climate change and habitat loss using new technologies and new policies. As a bandage for the short term, chemistry in service of endangered species is needed.

“Medicinal chemists interested in preventing extinction are encouraged to talk to zookeepers, foresters, veterinarians, entomologists, wildlife rehabilitators and conservationists to learn about the challenges and solutions where conservation medicine could make an impact, and to share their wisdom from the frontlines of drug discovery.”

Cernak is pushing for a new, impactful field of science.

“At the higher level, my mission is to have pharmaceutical companies be involved in this space and young scientists view this as the field they want to go into—a field that doesn’t really exist at this point,” he said. “A more immediate goal is fundraising and more research as the field and the value of the field is established.”

From deadly fungus decimating Panamanian golden frogs, cancerous tumors killing loggerhead turtles and the numerous pests and illnesses sickening plants such as the hemlock tree, there is no shortage of challenges for conservation medicine to tackle.

One of those challenges may be preventing a disease from threatening public health.

“In January, 96% of sea lion pups in Argentina died in January from avian flu. If it reaches humans, what are we going to do?” Cernak said. “There may be just five akikiki songbirds left in the wild. They are dying from malaria and pox, diseases that can be treated in humans.”

Studying wildlife diseases could also provide critical insights to medicinal chemists focused on human health, he said, and possibly a new paradigm where drug development and dosing prediction models, which are currently trained heavily on pharmacokinetics in rodents, could be diversified.

“The problem is that too often, conservationists who are trying desperately to treat and save dwindling populations aren’t equipped with the latest pharmaceutical science and tools,” he said. “Given current knowledge gaps, they may not know which drug will work best or what the right dosage might be for an endangered species.”

Bringing chemists and pharmacists into the conservation fold isn’t meant to diminish veterinarians and conservation groups, but to blend their experience and expertise and achieve the same goals of saving lives—and the ecosystem, Cernak said.

“Modern medicine could prevent the extinction of endangered species. Wildlife disease is a major driver of the current mass extinction yet therapeutic intervention in nonhuman species remains poorly understood,” he said. “In zoos, botanical gardens and animal rehabilitation centers, many diseases are treatable, but the understanding of medicine for endangered species lags far behind our current understanding of human medicine.”

At this moment, Cernak’s lab is not only researching faster, safer pharmaceutical development for humans but also testing the Panamanian golden frogs afflicted with a fungus that threatens their existence.

Cernak supports the Centers for Disease Control and Prevention’s concept of One Health, which recognizes the connection between the health of people, animals and the environment.

“We look at plants and animals the same,” he said. “The concept of One Health Pharmacy—plants, humans and animals—is we treat any that are sick or in need.”

Cernak’s lab has advanced the use of artificial intelligence and other technology in speeding up the process of drug discovery. He said that only increases the opportunities to help animals and plants sooner than later.

“Streamlining drug and agrochemical discovery with automation and artificial intelligence is likely to usher in a future era of accelerated medicinal invention tailored to specific patient populations,” Cernak and team wrote in their paper.

“While it may still be decades away, one can imagine a future where it is possible to feed a chatbot prompts like, ‘Invent a single-dose antiviral for elephant endotheliotropic herpesvirus with optimal pharmacokinetic properties for Asian elephants.’ Exciting applications of medicinal chemistry on threatened and endangered species are beginning to offer hope.”

Cernak’s co-authors include: Tesko Chaganti, a student at Canton High School, Canton, Michigan; Chun-Yi Tsai, a graduate student in U-M’s Department of Chemistry; Yu-Pu Juang, a postdoctoral researcher in the Cernak Lab; and Mohamed Abdelalim, a visiting research investigator at U-M.

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Mary River's rare, endangered species numbers are falling, but scientists aren't giving up

The first extensive study of one of Australia's most unique rivers in decades has revealed the rare and endangered species that call it home aren't bouncing back like they should be.

Queensland's Mary River is home to the prehistoric Australian lungfish and the critically endangered Mary River cod.

Professor Mark Kennard, from Griffith University's Australian Rivers Institute, is part of a collective monitoring the Mary River, which winds northwards from the Sunshine Coast.

"You know this might be our last best chance to do something to recover these species before it's too late," he said.

Queensland's Mary River is home to the prehistoric Australian lungfish, the critically endangered Mary River cod and the endangered Mary River turtle — famous for breathing through its bum.

Professor Kennard has caught and counted fish and turtles at nearly 60 sites since September and said Mary River cod numbers were particularly low.

"We caught about 9,000 fish but only 30 were Mary River cod and most of them were big or adults, so that could show there's been poor breeding success," he said.

They found nearly 120 Australian lungfish, but breeding didn't look successful there either.

There was happier news when it came to the turtles though, with Mary River turtles discovered in the creeks and streams that run into the river for the first time.

New ideas trialled

The Mary River is one of the few free-flowing rivers in eastern Australia without a big dam, rising in the Sunshine Coast hinterland and emptying into the Great Sandy Strait at River Heads, south of Hervey Bay.

But it's been battered by floods, droughts, farming and invasive species, including the pest fish tilapia whose numbers were up in this survey.

Years of hard work have gone into rehabilitating the river and restocking a range of rare and endangered native fish and turtle species.

Professor Kennard said the results haven't been as promising as hoped, but there were a range of new ways to intervene.

"We're trialling different designs of hollow logs and woody structures, hoping the cod will spawn in those," he said.

"We're also enhancing the habitat for baby turtles with sticks and snags in the water, so they can hatch and hide in there to protect them in the first year or two of life."

Sharing knowledge for the future

The project is also exploring new ways to bring traditional owners, land care groups and scientists together.

Collecting and sharing cultural knowledge where it is appropriate is part of that.

Jinibara man BJ Murphy visited parts of the river for the first time during the study.

He rediscovered the connection between the staghorn fern and the Australian lungfish, which both share the Jinibara name of Dala.

"Working with these groups, getting on country, slowing down and relearning," Mr Murphy said.

"That's been a special moment for me in this."

He said getting access to cultural sites could be a challenge because of private ownership, but the study had helped to overcome that.

"I think we're in a good turning point, coming together and working with science."

Rehabilitation takes teamwork

Better access to private land has been a major game changer for scientists too, with more farmers who lease or own tracts of the Mary River granting access during the study.

Tom Ryan's place is one of the properties being used.

"They're [the scientists] very passionate and I'm happy to have them here," Mr Ryan said.

He said he was working to rehabilitate his place by planting 1,000 trees.

"We want to leave the land in much better conditions than when I found it. If I can leave it that much better that will be important to me," he said.

Working together to rescue the region

The scientists involved in the study spend extra time together too, which they said builds a strong base for long-term research.

They camp together and share meals on each trip.

Burnett Mary Regional Group chief executive Tom Espinoza said that was key to success.

"In the modern world in meeting rooms you don't establish those connections," he said.

"Here you have to engage on a whole different level because you're sleeping next to each other in tent. Well, snoring next to each for me primarily!"

Mr Espinoza said it was hoped the project would span at least a decade.

"In this group, we've got older heads who are rusty in the knees and hips to get the field work done but we've also got a younger generation here, getting in, doing the work, building their knowledge," he said.

The project is currently supported with a combination of state and federal funding including Australian-Queensland Disaster Recovery Funding Arrangements and the National Environmental Science Program's Resilient Landscapes Hub.

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