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Science in support of management and conservation of threatened and endangered species

What do gray wolves, manatees and bears have in common? They are just a few of the species that are part of an important USGS research priority that informs U.S. Fish and Wildlife Service (USFWS) decisions for endangered and threatened species under the Endangered Species Act (ESA). 

The ESA provides federal protections for at-risk species and addresses the threats they face. Cooperative conservation efforts supported by USGS science can help stabilize a species to a point where federal listing can be avoided, inform the decision to downlist a species from endangered to threatened, or can lead to the delisting of a recovered species.

Downlisting is the reclassification of a species from endangered to threatened. Delisting is the removal of species from the Federal Lists of Endangered and Threatened Wildlife and Plants, also known as the endangered species list. Species showing signs of improvement and successful recovery efforts can result in downlisting or delisting actions.

USGS scientists collaborate with federal, state, tribal, and non-governmental partners to provide the science needed for conservation management decisions on many species and their habitat before listing is necessary. Get to know a bit about a few of the species where USGS science has aided in collaborative species conservation across the Nation.

Image: Wolf in Yellowstone National Park
Wolves were reintroduced to Yellowstone National Park in 1995 and 1996.(Credit: Arthur Middleton, University of Wyoming, U.S. Geological Survey. Public domain.)

The gray wolf is an ecologically important carnivore found in varied habitats such as forests, grasslands, and mountainous areas throughout the northern hemisphere. Direct impacts of human settlement on wolves and their habitat led to greatly reduced populations by the 1930s, and in 1978 the gray wolf was listed as endangered across the contiguous U.S. and Mexico and threatened in Minnesota. In the 1990s, gray wolves were reintroduced to Yellowstone National Park in an effort to recover the population. USGS research on wolf ecology and population dynamics was fundamental to the 2011 decision to delist this population. Due to a reduction of threats and collaborative management and conservation, the species has recovered throughout much of its range.


Male Okaloosa darter
Male Okaloosa darter (Public domain.)

The Okaloosa darter is about two inches long, weighs mere ounces and is part of a small group of fishes most often found in clear, fast-flowing streams. Its range is limited, only being found in  a small portion of northwestern Florida. This played a role in the darter being vulnerable to extinction and its ESA listing in 1973. Most of the species’ range is within Eglin Air Force Base, which led to a partnership between the USGS and the Department of Defense (DOD) to find ways for compatible management of darter habitat, land use and base operations. USGS science documented population increases and improved habitat conditions, leading to the 2011 decision to downlist the Okaloosa darter from endangered to threatened.  The USGS cooperative efforts with the DOD on population and habitat restoration continue in support of the management goal of delisting.

USGS Researcher with Manatee
USGS researcher collects data on manatee in Florida spring. (Credit: Bob Bonde, USGS. Public domain.)

In the United States, the West Indian manatee is found along the Atlantic coast from Florida to North Carolina, though a few individuals have been known to go as far north as a New England. The species is also found in the Gulf of Mexico from Florida to Texas, and in the Caribbean along the coasts of Puerto Rico, Central America, and northern and eastern South America. Manatees feed on aquatic vegetation and use brackish, freshwater, and marine habitats, and loss of any of these environments can negatively affect their populations.  Manatees have a low birth rate, which makes population recovery a challenge, and the species has been protected since 1967. Over four decades of USGS collaborative research on manatee habitat and movements, populations, health and genetics were considered in a 2017 decision to downlist them from endangered to threatened. USGS scientists will continue to monitor and analyze manatee population dynamics to inform management needs toward the ultimate goal,  recovery of the species.

Louisiana Black Bear and Cubs
Louisiana Black Bear and Cubs (Public domain.)

Delisted in 2016, the Louisiana black bear is a subspecies of the American black bear which historically inhabited east Texas, all of Louisiana, and southwestern Mississippi. Concerns about habitat fragmentation and a reduction to only three breeding populations led to its ESA listing in 1992. USGS researchers found that litter size, life history and biology showed stable or increasing populations based on scientific models. USGS efforts, combined with USFWS agreements with private land owners, helped confirm that the threats that existed previously were reduced enough to justify delisting.

Mother grizzly and cub at Gibbon River, Yellowstone National Park.
A USGS grizzly bear researcher snapped this picture of a mother grizzly bear and her cub in Yellowstone National Park. Adult females are the most important segment of the grizzly bear populations because they are the reproductive engine. (Credit: Frank van Manen, USGS. Public domain.)

Once found from the Pacific Ocean to the Great Plains, the grizzly bear by the late 1960s only occupied about two percent of its historic range in the lower 48 states due to hunting and habitat loss. In 1975 grizzly bears in this region were listed as threatened under the ESA. The USGS leads the Interagency Grizzly Bear Study Team which has been conducting research on grizzlies in the Yellowstone ecosystem for over 40 years. In 2017 the Yellowstone population of grizzly bears was delisted and the USGS provided more than 100 research products that were used in the decision to delist that population. The USGS continues coordinated research and monitoring of the Yellowstone grizzly bear population since the delisting and plays an important role providing objective science to many stakeholders, including the states of Montana, Wyoming, and Idaho that now have management authority.

Walrus on the shore
Walruses gathered by the tens of thousands in September 2013 to rest on the shores of the Chukchi Sea near the coastal village of Point Lay, Alaska. Walruses are finding it increasingly difficult to remain offshore in over their preferred foraging grounds in the eastern Chukchi Sea due to unprecedented loss of sea ice in the autumn, which has completely disappeared during 5 of the past 7 years. Drifting sea ice gives walruses a platform to rest on between foraging dives. Without sea ice walruses turn to shore to rest, which forces them to either to commute offshore foraging grounds or to forage near­shore over lower quality foraging grounds. The USGS Walrus Research Project is focused on tracking tagged walrus to understand how a loss of sea ice may be affecting the walrus. (Photo taken during USGS research efforts permitted under US Fish and Wildlife Service Permit No. MA801652­3) (Credit: Ryan Kingsbery, USGS. Public domain.)

The Bering and Chukchi seas of Russia and Alaska are home to the Pacific walrus. This large marine animal is dependent on drifting sea ice, a critical resource to walruses that provides a resting platform between feeding and for breeding. Over the last 30 years, the Chukchi Sea has experienced a dramatic decrease of sea ice and USGS science addresses how the changing sea ice environment and the associated stressors affect walrus populations. The Pacific walrus is of great importance to Alaska Native subsistence hunters, and this science is used to inform the co-management of walruses by USFWS and Alaska Native tribal organizations. In 2017 the USFWS published its final decision not to list the Pacific walrus as threatened or endangered, based, in part, on USGS science on walrus biology, distribution, mortality and projections of sea ice coverage. USGS scientists continue to work with USFWS to update the scientific assessments of the Pacific walrus as new information is gathered.

Image: Nesting Bald Eagle at Blackwater National Wildlife Refuge
A nesting bald eagle at Blackwater National Wildlife Refuge, which is home to the largest breeding population of American bald eagles on the East Coast, north of Florida. The platform was provided by the Refuge for use by nesting birds of prey. (Credit: Alex Demas, USGS. Public domain.)

Nesting in tall trees located near coastal areas, lakes, and rivers, bald eagles are monogamous and pair for life. Distinguished by a white head and white tail feathers bald eagles are powerful, brown birds that may weigh 14 pounds and have a wingspan of 8 feet. Removed from the endangered species list in 2007 after nearly disappearing from most of the United States, the bald eagle now thrives. USFWS research on eggshell thinning led to banning DDT, a synthetic organic compound used as an insecticide. The first studies of DDT by scientists were conducted in 1943, and the first papers were published in 1946, just after the end of the Second World War. A major breakthrough in DDT research occurred in 1969 when Patuxent researchers, then part of the USFWS, published results of research linking eggshell thinning with DDT in the food of birds. Research clearly indicated that DDT obtained in the food eaten by birds changed to DDE (dichlorodiphenyldichloroethylene), and then physiologically affected the process of calcium deposition on the eggshell of the birds’ eggs. Although initial eggshell thinning studies were conducted with mallards and black ducks, the findings had major implications with other species, especially fish-eating birds such as the brown pelican, osprey, and bald eagle. After learning of this research, Congress in 1972 passed laws that banned DDT and related pesticides, leading the way for bald eagle recovery. Though no longer a federally listed species, the bald eagle remains protected under the Migratory Bird Treaty Act (MBTA) and the Bald Eagle and Golden Eagle Protection Act (Eagle Act)


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