Climate Change and Drought

Aquatic species, aquatic habitats, and ecological drought.—Freshwater fisheries are recreationally valuable and major economic drivers of local economies in the northern Rocky Mountains. Climate change threatens many of these fisheries through drought-induced reductions in streamflows and increased water temperatures. In fiscal year 2023, our scientists initiated a project, funded by the NOAA’s National Integrated Drought Information System, to develop a regional drought early warning system across the northern Rocky Mountains of Montana. The project will result in a tool providing forecasts of trout abundance based on drought risk with short-term (3–6-month) and long-term (1–2-year) outlooks. Our scientists will also evaluate the effects of different streamflows caused by management actions on trout abundance, allowing managers to identify critical instream flows and develop management strategies for a range of drought severities. Ultimately, this project will provide fisheries managers with tools to manage Montana’s popular trout fisheries in various climate change and drought conditions.

Solution-based approaches to climate adaptation.—To improve climate change vulnerability assessments for species and better inform and prioritize management actions, our scientists, in collaboration with other USGS scientists, have been developing a framework to incorporate adaptive capacity into the decision-making process. Adaptive capacity is the ability of species or populations to cope with climate based on changes in genetics or behavior or by shifting to more suitable ranges or microhabitats. Additionally, our scientists have been placing adaptive management within the Resist-Accept-Direct Framework where managers decide if they actively manage to maintain contemporary or historical ecological characteristics, do not intervene, or nudge the ecosystem toward a particular state or function. Our science can provide managers with useful frameworks at the subspecies, species, population, or ecosystem scales to inform management in climate change or ecosystem transformation scenarios.

Quantifying glacier response to climate for international and interagency partners.—Climate-induced glacier retreat can affect cold-water habitats and the species that rely on them, create flood hazards by altering glacier meltwater dynamics, and affect tourism- and recreation-based economies. To study climate-glacier dynamics, we perform USGS Benchmark Glacier Project research, which involves maintaining the longest, most continuous field-based record of glacier mass balance (gain or loss of snow and ice) in North America. During fiscal year 2023, our scientists collaborated with the USGS Alaska Climate Adaptation Science Center and USGS Alaska Science Center to engineer a data visualization platform that enables National Park Service and FS partners to access new datasets on glacier ice thickness, surface elevation change, and glacier motion. This data visualization platform and our accompanying research on glacier vulnerability enable partners to anticipate and respond to the consequences of glacier change in the western United States and Alaska.

Species at Risk

Native trout.—In the West, trout are among the most culturally, economically, and ecologically important groups of freshwater fishes. However, climate change, invasive species, and habitat modifications threaten native species like westslope cutthroat trout, Yellowstone cutthroat trout, bull trout, and Lahontan cutthroat trout. Our scientists are using long-term monitoring and climate data to assess the vulnerability of westslope cutthroat trout and federally threatened bull trout in the Rocky Mountains region and evaluate conservation management strategies. They are advancing a novel biosurveillance technology based on geochemical tracers in water and fish ear bones (otoliths) to identify invasion dynamics of lake trout, which threaten bull trout. Our scientists have also been using innovative approaches that involve a combination of field surveys, geographical information system (GIS) data, and remote sensing techniques to assess the habitat and status of federally threatened Lahontan cutthroat trout in the Great Basin. Our research to assess the vulnerability of native trout and their habitat in the West provides our partners with critical information needed to understand the status of trout fisheries, what threatens them, and what tools can be used to mitigate those threats.

Western bumble bees.—Pollinators support the agriculture industry and pollinate the plants that provide high-calorie, nutritious resources like seeds, nuts, and berries that humans and wildlife rely on. There has been a global decline in pollinators, and the once-common western bumble bee is no exception. The western bumble bee is a native pollinator that has undergone severe population declines and is a candidate for listing per the Endangered Species Act. Our science directly supports a FWS Species Status Assessment for the western bumble bee by evaluating the effects of climate change and pesticides on this species across the western United States. Several tools are being developed to efficiently collect baseline information on entire pollinator communities and gather key pollinator data while minimizing risks to this imperiled species.

Grizzly bears.—The Northern Rocky Mountain Science Center leads the Interagency Grizzly Bear Study Team (IGBST), an interdisciplinary group of scientists responsible for the long-term monitoring and research of grizzly bears in the Greater Yellowstone Ecosystem. The IGBST celebrated 50 years of service during fiscal year 2023, and the team’s half-century mark comes at a pivotal moment in history for grizzly bear conservation. The State of Wyoming filed a 2022 petition to delist the Yellowstone National Park grizzly bear population; the FWS is updating their Species Status Assessment; and Federal, State, and Tribal partner agencies of the Yellowstone Ecosystem Subcommittee are revising the 2016 Conservation Strategy. The IGBST met this pivotal moment by implementing major improvements to long-term grizzly bear demographic research by integrating count, survival, and reproduction data to provide more accurate estimates of Greater Yellowstone Ecosystem grizzly bear population size and vital rates. The team also completed a study that offered important insights into factors affecting grizzly bear body condition, an issue that plays a pivotal role in policy decisions.

Louisiana black bears.—Our bear research portfolio extends to other bear species and conservation standings. A subspecies of the American black bear found in the American Southeast—the Louisiana black bear—was listed as threatened per the Federal Endangered Species Act in 1992 but was delisted in 2016. Since Louisiana black bears were delisted in 2016, our scientists have been monitoring them and providing yearly results of those efforts to the Louisiana Department of Wildlife and Fisheries and the FWS. The final post-delisting monitoring report was delivered to partners during fiscal year 2023 and provided a comprehensive evaluation of 14 years of capture-recapture data, including estimates of bear population abundance, annual population growth rates, female survival rates, and recruitment.

Amphibians.—Amphibians are in global decline owing to habitat loss, introduced species, disease, and contaminants. Our science is an important tool in understanding amphibian threats and how to manage for them. In collaboration with other USGS centers, our scientists studied the effects of invasive American bullfrogs and their associated pathogens on native amphibian species in the American Southwest. Working with USGS collaborators from across the country, our scientists validated a nonlethal method to assess levels of methylmercury (which forms when bacteria interact with mercury in aquatic environments) accumulation in amphibians in 11 States. A total of 14 species were sampled, including threatened and endangered species and species proposed to be listed as threatened or endangered by the FWS. Our amphibian research evaluates the effectiveness of management actions, has the capacity to perform large-scale assessments, and provides managers with information about threats to amphibians.

Habitat in Changing Landscapes

Migratory wildlife.—Migration of ungulates is an important behavioral strategy that connects western landscapes and allows species to access high-quality forage and avoid severe weather. However, human-caused activities can introduce landscape features that may disrupt or intersect migration routes, with unknown consequences to wildlife. Our scientists documented the effects of wind turbine facilities and their construction on female pronghorn migration behavior in Wyoming. Migration science can help wildlife managers and energy developers draft informed strategies about siting decisions for new energy facilities that could limit wildlife and energy development conflicts, including in critical pronghorn habitats. Pronghorn have larger and more unpredictable migratory movements than other North American ungulates, so this research highlights our capacity to provide valuable insight into the migratory behavior of difficult-to-study wildlife species.

Energy development.—As offshore wind energy development expands, the need to understand how flying wildlife (birds, bats) interact with wind energy facilities becomes increasingly important. We have new offshore wind energy research projects in the Great Lakes and the Gulf of Mexico to address these needs. Using biological radar, our scientists will collect abundance and behavior data on flying wildlife. U.S. Geological Survey scientists, including the Northern Rocky Mountain Science Center lead, collected data for the Gulf of Mexico project in September 2023 from a NOAA research vessel to test an offshore radar prototype. Data from these projects will be used to address technical issues of collecting radar data in open-water environments, inform decisions on where to locate wind energy facilities, and provide information to wildlife and energy facility managers that can be used to limit costly wind energy and wildlife conflicts.

Invasive Species and Wildlife Disease

Rapid eDNA Assessment and Deployment Initiative & Network (READI-Net).—Once established, aquatic invasive species can be ecologically destructive, expensive to manage, and difficult—if not impossible—to eradicate. We lead a national USGS project called READI-Net that uses eDNA as an early detection tool for aquatic invasive species, allowing managers to initiate a rapid management response. The READI-Net project operates within the Department of the Interior’s National Early Detection and Rapid Response Framework and offers Federal, State, and Tribal agencies; municipalities; and nongovernmental organizations the technology (for example, autonomous eDNA samplers), guidance, and communication framework to properly sample, analyze, and distribute the results to end users and decision makers. During fiscal year 2023, READI-Net engaged with partners to develop an eDNA autosampler capable of taking more than 140 samples, tested another eDNA autosampler design in multiple field deployments, and worked on incorporating high-throughput techniques. With READI-Net, partners and stakeholders can quickly detect new invasive species, which is the first step to stopping an invasion as early as possible.

Identifying CWD transmission hotspots.—Chronic wasting disease is fatal and is freely transmitted among different species of ungulates (deer, elk, moose). There is no treatment or vaccine for the disease. Therefore, it is critical to identify hotspots of disease transmission and understand why high levels of CWD transmission are occurring on the landscape. Our scientists, in collaboration with the USGS Northern Prairie Wildlife Research Center, are addressing State, Federal, and Tribal partner needs on the Wind River Reservation in Wyoming by identifying CWD transmission hotspots in adult mule deer and white-tailed deer. U.S. Geological Survey scientists will use deer movement, density, and disease data to estimate CWD transmission hotspots. This research will not only provide information on potential disease transmission hotspots but will also identify the mule deer population component (migrating compared to nonmigrating) that may be contributing more to the high CWD prevalence in the region.