NatureServe estimates that 34% of plant species and 40% of animal species in the U.S. are at risk of extinction. The organization also estimates that 41% of ecosystems are at risk of range-wide collapse.[1,2]
NatureServe is a non-profit that collects data from a network of more than 60 governmental and non-governmental programs in the U.S. and Canada.[3] They are generally viewed as providing the most credible and comprehensive evaluation of the state of U.S. biodiversity.
Their Conservation Status Ranks divide “at risk” species into 4 categories: possibly extinct, critically imperiled, imperiled, or vulnerable.[4] We use NatureServe figures throughout this page, adding other credible data where available.[5,6]
NatureServe (2023) Biodiversity in Focus: United States Edition. NatureServe: Arlington, VA, p. 8. https://www.natureserve.org/sites/default/files/NatureServe_BiodiversityInFocusReport_medium.pdf
For on-line data. See: NatureServe, Conservation Status Assessment.
https://www.natureserve.org/conservation-status-assessmentBiodiversity in Focus: United States Edition, p. 4. [“For nearly 50 years, NatureServe has developed data and methods to comprehensively assess the conservation status of North American plant and animal species. As the authoritative source for data on U.S. and Canadian biodiversity, NatureServe is uniquely suited to answer questions about species and ecosystems and the extent to which they are threatened.”]
Biodiversity in Focus: United States Edition, p. 7.
IUCN Red list (2024) Summary Statistics, Table 5: number of threatened species in each major taxonomic group by country in North America, and Table 6a: number of animal species. https://www.iucnredlist.org/statistics [The IUCN Red List database assesses endangered species by country. In 2024, the overall number of “threatened” species in the U.S. (of species assessed) by major taxonomic group included 1,213 animals (including fish and invertebrates), 749 plants, and 88 fungi, for a total of 2,050 species. Endangered species are classified as vulnerable, endangered, or critically endangered.]
WWF (2024) Living Planet Report 2024 – A System in Peril. WWF, Gland, Switzerland, Foreword, p. 29. [Report estimates in North America a 39% average decline in the size of monitored wild vertebrate species populations in the period from 1970 to 2020.]
According to NatureServe, 40% of animal species in the U.S. are at risk of extinction.[1]
Chart data from NatureServe (2023) Biodiversity in Focus: United States Edition. NatureServe: Arlington, VA, p. 10 & footnote 7. [“It includes animals in comprehensively assessed taxonomic groups native to all 50 states. The reported percentage of species at risk is a best estimate that assumes that the same percentage of unassessed species are at risk as species whose conservation status has been assessed.”]
An estimated 34% of plants species are at risk of extinction.[1]
NatureServe (2023) Biodiversity in Focus: United States Edition. NatureServe: Arlington, VA, p. 10.
According to NatureServe, an estimated 41% of all terrestrial ecosystems are at risk of range-wide collapse.[1,2]
Temperate Forests are ~40% at risk. Grasslands are ~50% at risk. Wetlands are ~40% at risk.
About half of all plants and animals in the U.S. listed as threatened or endangered depend on wetlands for survival.[3]
Ecological Society of America (2012) Biodiversity. https://www.esa.org/wp-content/uploads/2012/12/biodiversity.pdf [“Ecosystem: Any geographic area with all of the living organisms present and the nonliving parts of their physical environment. Involves the movement and storage of energy and matter through living things and activities.”]
NatureServe. (2023) Biodiversity in Focus: United States Edition. NatureServe: Arlington, VA, [“At the ecosystem level, NatureServe focuses on terrestrial communities.” at p. 7. “Collapse involves a transformation of identity, loss of defining features, and/or replacement by a novel ecosystem. It occurs when all ecosystem occurrences lose defining biotic or abiotic features and when characteristic native biota are no longer sustained.” at pp. 12-13. “At-risk” ecosystems are categorized as either “imperiled” or “vulnerable.”]
Lang, M. W., et al., (2024). Status and Trends of Wetlands in the Conterminous United States 2009 to 2019. U.S. Department of the Interior; Fish and Wildlife Service, Washington, D.C., p. 6. [“Wetlands enhance water quality, control erosion, maintain stream flows, sequester carbon, and provide a home to about half of all threatened and endangered species.”]
Yes, freshwater species, including amphibians, snails, mussels, crayfish, and many aquatic insects are at greatest risk.[1,2]
The USGS estimates that amphibians, including frogs, toads, and salamanders, are experiencing serious declines in the U.S. at an annual 3.79% average decline in overall populations.[3]
“Amphibians are good indicators of significant environmental changes. Amphibians, unlike people, breathe at least partly through their skin, which is constantly exposed to everything in their environment. Consequently, their bodies are much more sensitive to environmental factors such as disease, pollution, toxic chemicals, ultraviolet radiation, and habitat destruction. The worldwide occurrences of amphibian declines and deformities could be an early warning that some of our ecosystems, even seemingly pristine ones, are seriously out of balance.”[4]
NatureServe. 2023. Biodiversity in Focus: United States Edition. NatureServe: Arlington, VA, p. 11. [“As a group, species associated with fresh water, including amphibians, snails, mussels, crayfish, and many aquatic insects, have the highest percentage of at-risk species, highlighting the importance of conservation strategies to protect freshwater ecosystems.”]
Stein, B. A., et al., (2018). Reversing America’s Wildlife Crisis: Securing the Future of Our Fish and Wildlife. Washington, DC: National Wildlife Federation, p. 3. [“America’s freshwater animals have been particularly hard hit and approximately 40 percent of the nation’s freshwater fish species are now rare or imperiled.”]
U.S. Geological Survey (n.d.) Why are amphibian populations declining? https://www.usgs.gov/faqs/why-are-amphibian-populations-declining
U.S. Geological Survey (n.d.) Why are amphibian populations declining?
There are approximately 200,000 known species of fungi, plants, and animals in the U.S.[1,2] Including species still undiscovered, there are perhaps 500,000 or more.[3]
Wilcove, D. S., & Master, L. L. (2005). How many endangered species are there in the United States? Frontiers in Ecology and the Environment, 3(8), 414-420, p. 414. [“A recent tally found that over 200,000 species of fungi, plants, and animals have been described to date in the US.”]
NatureServe (January 1, 2000) Precious Heritage: The Status of Biodiversity in the United States. https://www.natureserve.org/publications/precious-heritage-status-biodiversity-united-states [“More than 200,000 species are now known from the United States – a figure double the previous estimate. This figure, however, includes only those species that scientists have formally studied and named, and may represent fewer than half the plants, animals, and microbes yet to be discovered in the United States.”]
Dirzo, R., & Raven, P. H. (2003). Global state of biodiversity and loss. Annual review of Environment and Resources, 28(1), 137-167, p. 147. [“Even for relatively well-known areas like the United States, the rate of discovery suggests that no more than a third to a half of the estimated total 500,000 to 750,000 species of organisms have yet been discovered.”]
Of NatureServe’s assessed native species in the U.S., there are ~11,500 species of plants and animals that are considered at risk. (These are in 3 categories: critically imperiled, imperiled, or vulnerable.)[1]
Of NatureServe’s assessed native species, there are ~7,300 species of plants and animals that are considered critically imperiled or imperiled.[2]
NatureServe Explorer. Search criteria United States/Species/National Status N1 (critically imperiled), N2 (imperiled), N3 (vulnerable) = 11,479. https://explorer.natureserve.org/
NatureServe Explorer. Search criteria United States/Species/National Status N1 (critically imperiled), N2 (imperiled) = 7,269.
The Endangered Species Act of 1973 (ESA) is the primary law for assessing and mitigating biodiversity loss in the United States; the federal agencies responsible for administering the ESA are the U.S. Fish and Wildlife Service (FWS) and the National Marine Fisheries Service.[1,2]
U.S. Fish & Wildlife Service. Endangered Species Act of 1973, As Amended through the 108th Congress. https://www.fws.gov/media/endangered-species-act
Congressional Research Service (March 4, 2021) The Endangered Species Act: Overview and Implementation, R46677.
There are ~1,700 species ESA-listed as either endangered or threatened in the U.S.[1]
NatureServe’s comparable figures (as noted above) are much larger. Many reports and organizations have pointed out that the number of species listed under the ESA is just a small share of the number endangered or threatened.[2,3]
Considering all known species in the U.S. (about 200,000), a 2005 report based on NatureServe data found that “somewhere between 14,000 – 35,000 imperiled species (roughly 7–18% of the nation’s known plants, animals, and fungi) appears to be a reasonable, conservative estimate for the US. This total is more than an order of magnitude greater than the number of species currently protected under the ESA.”[4] Twenty years later, this estimate would presumably be much larger.
U.S. Fish & Wildlife Service (January 5, 2025). ECOS Environmental Conservation Online System, Listed Species Summary (Boxscore). https://ecos.fws.gov/ecp/species-reports [As of January 5, 2025, a total of 1685 species. The U.S. listings include those populations in which the U.S. shares jurisdiction with another nation.]
Evans, D.M. et al., (2016) Species recovery in the United States: Increasing the effectiveness of the endangered species act, Issues in Ecology, The Ecological Society of America, p. 1. [“…at least 10 times more species than are actually listed probably qualify for listing.”]
Stein, B. A., et al., (2018). Reversing America’s Wildlife Crisis: Securing the Future of Our Fish and Wildlife. Washington, DC: National Wildlife Federation, p. 2. [“Listings under the Act are not an accurate barometer of the overall conservation status of U.S. species, however, and the number of species of conservation concern is far higher…”]
Wilcove, D. S., & Master, L. L. (2005). How many endangered species are there in the United States? Frontiers in Ecology and the Environment, 3(8), 414-420, p. 414. [“A recent tally found that over 200,000 species of fungi, plants, and animals have been described to date in the US.”]