Clint Muhlfeld, Ph.D.

There is an urgent need to consider more aggressive and direct interventions for conservation of freshwater fishes threatened by invasive species, habitat loss, and climate change. Conservation introduction - moving species to areas outside their previous range, where conditions are predicted to be more suitable - is one type of translocation strategy that fisheries managers can use to establish new conservation populations and potential refugia (safe havens). To date, however, there are few examples of successful conservation-based introductions, and many attempts fail to establish new populations likely due in part to inadequate assessment of environmental factors influencing success prior to implementation.

After 14,000 years of surviving extreme environmental events, such as floods, fires and glaciations, Glacier’s greatest native trout is at high risk of disappearing from several streams and lakes east and west of the Continental Divide. The decline of westslope cutthroat trout (Oncorhynchus clarkii lewisi; WCT) in Glacier National Park (GNP) has been attributed to the establishment of nonnative fish species, which consistently displace and hybridize with native cutthroat trout populations in systems where they have been introduced. In response to these declines, GNP wants to develop a management plan to protect and restore WCT in GNP; however, little information exists regarding the distribution and genetic composition of WCT populations throughout the park. This research project will aid in this effort by assessing the genetic status, population structure, and evolutionary history of WCT throughout GNP using stream electrofishing and non-lethal genetic testing. This information may be used to inform management actions in GNP and elsewhere in the western United States.

Future climate change is expected to dramatically alter the structure and function of freshwater ecosystems that support salmonid species. The response of salmonids to climate change will vary through space and time and manifest in both known and currently unknown ways. A potentially rich source of understanding of how salmonids interact with climate lies in a unified retrospective analysis of observed climate and population data in diverse habitats across the United States.

The Transboundary Flathead and Kootenai Basins in Montana and British Columbia host some of the most diverse and unique native aquatic ecosystems throughout North America. Headwaters of these basin feed into Waterton-Glacier International Peace Park (U.S. and Canada) and Flathead Lake, and Lake Koocanusa and the Kootenai River in the U.S.   Despite the tremendous historical and ecological value of the region, the headwaters in the Flathead were targeted for coal mining, which may threaten water and habitat quality, migratory fish populations, and aquatic life downstream. A history of coal mining and coalbed methane extraction in the headwaters of the Elk River, which drains into Lake Koocanusa, suggest that upstream land use practices are producing sediment and water pollution that degrade waters downstream. Since 2008, the USGS has led an aquatics research project, working with Federal, State, and International partners, to help understand the effects on species and aquatic ecosystems and to provide information to support of the Transboundary Flathead and Kootenai Ecosystems.

Climate warming in the mid- to high-latitudes and high-elevation mountainous regions is occurring more rapidly than anywhere else on Earth, causing extensive loss of glaciers and snowpack. The loss of glaciers in Glacier National Park (GNP) is iconic of the combined impacts of global warming and reduced snowpack−all remaining 25 glaciers are predicted to disappear by 2030. These changes will impact many aquatic species, particularly range-restricted mountaintop species that show strong reductions in range due to changes in temperature and stream flow. However, little is known about the effects of climate change on stream biota, especially invertebrates, in GNP and other mountain ecosystems in the USA.