What are the differences between endangered, threatened, imperiled, and at-risk species?
Under the Endangered Species Act (ESA), plant and animal species may be listed as either endangered or threatened. “Endangered” means a species is in danger of extinction throughout all or a significant portion of its range. “Threatened” means a species is likely to become endangered within the foreseeable future.'
States have their own ESA-type laws, so species can have different Threatened/Endangered statuses at the federal and state levels. The USGS typically refers to the federal status unless otherwise noted.
"Imperiled" or "at risk" are not legal terms under ESA, but more biological terms. Generally speaking, they are animals and plants that are in decline and may be in danger of extinction. Those terms can include species that are at low populations and near extinction but still not legally protected under ESA.
Learn more: USGS Threatened & Endangered Species
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U.S. Geological Survey science in support of the North American Bat Monitoring Program (NABat)
Bats make up one-fifth of all mammalian species worldwide and are found on every continent except Antarctica. They contribute to overall ecosystem health by suppressing pest insects and pollinating plants and spreading seeds. Eight North American bat species are listed as federally endangered or threatened, and more than one-half are of current...
Reichert, Brian E.; Soileau, Suzanna C.
Status and threats analysis for the Florida manatee (Trichechus manatus latirostris), 2016
Trichechus manatus (West Indian manatee), especially T. m. latirostris, the Florida subspecies, has been the focus of conservation efforts and extensive research since its listing under the Endangered Species Act of 1973. To determine the status of, and severity of threats to, the Florida manatee, a comprehensive revision and update of the manatee...
Runge, Michael C.; Sanders-Reed, Carol A.; Langtimm, Catherine A.; Hostetler, Jeffrey A.; Martin, Julien; Deutsch, Charles J.; Ward-Geiger, Leslie I.; Mahon, Gary L.
Early action to address an emerging wildlife disease
A deadly fungal pathogen, Batrachochytrium salamandrivorans (Bsal) that affects amphibian skin was discovered during a die-off of European fire salamanders (Salamandra salamandra) in 2014. This pathogen has the potential to worsen already severe worldwide amphibian declines. Bsal is a close relative to another fungal disease known as...
Adams, M.J.; Harris, M. Camille; Grear, Daniel A.
Using genetic research to inform imperiled and invasive species management
The long-term viability of species and populations is related to their potential to migrate, reproduce, and adapt to environmental changes. In the southeast United States, U.S. Geological Survey (USGS) scientists are providing resource managers with genetic information to improve the long-term survival and sustainability of the Nation's aquatic...
Hunter, Margaret E.; Pawlitz, Rachel J.
White-nose syndrome in bats: U.S. Geological Survey updates
White-nose syndrome (WNS) is a devastating disease that has killed millions of hibernating bats since it first appeared in New York in 2007 and has spread at an alarming rate from the northeastern to the central United States and Canada. The disease is named for the white fungus Geomyces destructans that infects the skin of the muzzle, ears, and...
Rogall, Gail Moede; Verant, Michelle
Lead poisoning in wild birds
Lead in its various forms has been used for thousands of years, originally in cooking utensils and glazes and more recently in many industrial and commercial applications. However, lead is a potent, potentially deadly toxin that damages many organs in the body and can affect all animals, including humans. By the mid 1990s, lead had been removed...
Lahner, Lesanna L.; Franson, J. Christian
Protecting Black-Footed Ferrets and Prairie Dogs against sylvatic plague
Scientists at the USGS National Wildlife Health Center (NWHC), in collaboration with colleagues at other federal agencies and the University of Wisconsin, are developing and testing vaccines that can be used to protect black-footed ferrets and prairie dogs against plague. The black-footed ferret is commonly regarded as the most endangered mammal...
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A Century of Habitat Loss Affects Genetics of Endangered Bird
A new study analyzes the genetic diversity and population structure of the California Ridgway’s rail, Rallus obsoletus, a state and federally-listed endangered bird. The results demonstrate that the so-called “rails” are experiencing negative genetic effects following more than a century of salt marsh habitat loss from agriculture, commercial salt production and urban development.
A Century of Habitat Loss Affects Genetics of Endangered Bird
A new study analyzes the genetic diversity and population structure of the California Ridgway’s rail, Rallus obsoletus, a state and federally-listed endangered bird. The results demonstrate that the so-called “rails” are experiencing negative genetic effects following more than a century of salt marsh habitat loss from agriculture, commercial salt production and urban development.
A Deadly Double Punch: Together, Turbines and Disease Jeopardize Endangered Bats
Drought and Wildfires Threaten the Endangered Mountain Yellow-Legged Frog (Los Angeles Times)
SOUTHERN CALIFORNIA — Wildfires are affecting endangered Mountain yellow-legged frogs in San Diego and other counties.
Community flood protection may also help endangered salmon to thrive
Building a river setback levee to reduce the risk of flood for a community may also help endangered fish species to thrive, according to the results of a novel computer model reported by the U.S. Geological Survey.
Magical Manatees
It may be hard to believe the legend that sailors long-at-sea once believed manatees to be mermaids. The manatee nickname the “Sea Cow” – named so for their affinity for grazing on vegetation and their slow, ambling way – just makes more sense. But a new U.S. Geological Survey video reveals that while they may be cow-like, they also have more than a bit of magical mermaid to them.
Long-term Prognosis for Florida Manatees Improves
The risk of extinction for the endangered Florida manatee appears to be lower, according to a new U.S. Geological Survey led study.
Culprit Identified in Decline of Endangered Missouri River Pallid Sturgeon
BOZEMAN – Pallid sturgeon come from a genetic line that has lived on this planet for tens of millions of years; yet it has been decades since anyone has documented any of the enormous fish successfully producing young that survive to adulthood in the upper Missouri River basin.
Captive Whooping Cranes Released Into the Wild
Four whooping crane chicks raised in captivity began their integration into the wild Saturday as part of the continuing effort to increase the wild population of this endangered species.
Endangered Desert Pupfish found in Research Ponds near the Salton Sea, Calif.
Researchers from the U.S. Geological Survey (USGS) have discovered a population of the endangered desert pupfish (Cyprinodon macularius)in constructed ponds along the southeastern shore of the Salton Sea, in south-central California.
A First: Endangered Puaiohi Birds Fledge Four Chicks in the Wild
A highly endangered native Hawaiian bird species has taken a small but significant step back from the brink of extinction. USGS biologists monitoring 14 captive-reared puaiohi released into the wild earlier this year by The Peregrine Fund say the birds are nesting and have already fledged four young.
Endangered Humpback Chub
Endangered humpback chub caught near the confluence of the Colorado River and Little Colorado Rivers in Grand Canyon.
Endangered Karner blue butterfly, Lycaeides melissa samuelis
Whooping Crane, Grus americana, adult and chick
Pima pineapple cactus
Pima pineapple cactus and vegetative offshoot, commonly called a pup, in the Altar Valley of south-central Arizona (November 2014).
Endangered Sonoran Tiger Salamander (Ambystoma mavortium stebbinsi)
A green and black endangered Sonoran tiger salamander (Ambystoma mavortium stebbinsi) on a tree branch
An Endangered Puaiohi (Small Mountain Thrush) in Hawaii
Many species of Hawaiian honeycreepers have persisted into the 20th century because high elevation rain forests on the islands of Kaua’i, Maui, and Hawai'i are cool enough to limit transmission of introduced avian malaria (Plasmodium relictum). Malaria transmission is tied closely to the effects of temperature on development of malarial parasites within their mosquito
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Green Sea Turtle Swimming in Dry Tortugas National Park
A green sea turtle, sporting a USGS satellite tag, swims the waters of Dry Tortugas National Park, Florida, USA. Note: All marine turtle images taken in Florida were obtained with the approval of the U.S. Fish & Wildlife Service (USFWS) and the Florida Fish & Wildlife Conservation Commission (FWC) under conditions not harmful to this or other turtles. The activity
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Female Pallid Sturgeon
Biologists prepare to perform ultrasound and an egg biopsy on female pallid sturgeon, radio code 30, to determine how close to spawning she is or whether spawning may already have occurred. Biologists from Montana Fish, Wildlife and Parks determined that code 30 eventually spawned in the Yellowstone River on July 19-20, 2012.
An Endangered Yellow-Legged Frog
USGS biologists are leading the monitoring and reintroduction effort of the Southern California mountain yellow-legged frog -- federally listed as endangered with only 200 wild adults remaining in the mountains surrounding Los Angeles County.
An Endangered Humpback Chub
The Colorado River basin supports one of the most distinctive fish communities in North America, including the federally endangered humpback chub (Gila cypha). One of only six remaining populations of this fish is found in Grand Canyon National Park, Arizona. USGS scientists and their cooperators are responsible for monitoring the Grand Canyon population. The number Grand
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