Clint Muhlfeld, Ph.D.
Research Associate Professor
Flathead Lake Biological Station, University of Montana
Ph.D. 2008. Fish and Wildlife Biology, Montana State University, Bozeman.
Dissertation: Behavioral, ecological, and fitness consequences of hybridization between native westslope cutthroat trout and nonnative rainbow trout
M.S. 1999. Fishery Resources, University of Idaho, Moscow.
Thesis: Seasonal habitat use and movement of redband trout in the Kootenai River drainage, Montana
B.S. 1994. Aquatic Biology, University of Montana, Missoula; University of Maine, Orono (1990-1993)
I am a Research Aquatic Ecologist for the USGS Northern Rocky Mountain Science Center stationed in Glacier National Park and Associate Research Professor at the University of Montana’s Flathead Lake Biological Station. My general research interests encompass the fields of aquatic ecology, fisheries biology, and conservation biology. My research goal is to understand how aquatic species interact with physical and biological templates over space and time to inform conservation and management. Specifically, my applied research focuses on assessing how human stressors – invasive species, habitat modification, and climate change – influence native salmonids and rare alpine macroinvertebrates in the Rocky Mountains of the United States and Canada.
My published research spans a range of scientific questions and conservation issues from examining the evolutionary and ecological impacts of invasive species on native fishes, assessing life history and genetic diversity of native salmonids, assessing the status of threatened freshwater species, investigating the impacts of dams and barriers on aquatic species and ecosystems, developing quantitative models (e.g., stream temperature, instream flow/habitat, bioenergetics, riverscape connectivity, population viability) to predict species’ responses to environmental change, to understanding and predicting the impacts of climate change on freshwater species and ecosystems.
I particularly enjoy collaboration and multidisciplinary research, and advising and educating graduate students working on various aspects of freshwater ecology and conservation biology. Currently, I actively participate on several regional, national, and international science teams that address natural resource issues facing aquatic ecosystems. My hope is that the ecological integrity of aquatic ecosystems will be conserved for future generations through research-informed management and education.
Science and Products
After 14,000 years of dominance, Glacier National Park’s (GNP) greatest native aquatic predator is at high risk of extirpation (local extinction) in several lakes on the western slopes of the Continental Divide. The decline of threatened bull trout in GNP is directly attributed to the invasion and establishment of nonnative lake trout, which consistently displace bull trout in systems where lake trout have been introduced. Lake trout have colonized almost every accessible lake to which bull trout are native on the west side of GNP and unless research-based management is implemented immediately, these ecologically unique populations face continued decline and likely extirpation.
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.
Salmonids – a group of coldwater adapted fishes of enormous ecological and socio-economic value – historically inhabited a variety of freshwater habitats throughout the Pacific Northwest (PNW). Over the past century, however, populations have dramatically declined due to habitat loss, overharvest, and invasive species. Consequently, many populations are listed as threatened or endangered under the U.S. Endangered Species Act. Complicating these stressors is global warming and associated climate change. Overall, aquatic ecosystems across the PNW are predicted to experience increasingly earlier snowmelt in the spring, reduced late spring and summer flows, increased winter flooding, warmer and drier summers, increased water temperatures, and expansion of invasive species. Understanding how the effects of climate change might influence habitat for native salmonid populations is critical for effective management and recovery of these species.
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.
Invasive species and hybridization (reproduction between different species or subspecies) – among the most serious threats to native species and biodiversity – provide some of the richest opportunities for “natural experiments” in evolutionary biology. New genomic technologies, combined with long-term hybridization studies in natural populations, provide exciting opportunities to advance our understanding of evolutionary mechanisms that influence hybridization, adaptation, and the spread of invasive species. Rates of hybridization and species invasion are increasing as a result of environmental change and introductions of nonnative species. However, interpreting the evolutionary and ecological significance of hybridization remains a conservation challenge.
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.
Climate change poses a serious threat to natural resources, biodiversity, and ecosystem services in the United States, especially in the Rocky Mountain Ecoregion. The Crown of the Continent Ecosystem (CCE) is considered one of the largest, most pristine, and biodiverse ecosystems in North America, spanning the northern Rocky Mountains of the United States and Canada. In the heart of the CCE is the Transboundary Flathead Watershed, a significant portion of which forms Waterton-Glacier International Peace Park, a World Heritage Site and Biosphere Reserve (Fig. 1). The Transboundary Flathead originates in British Columbia and flows into Montana and is considered one of America's most biodiverse river systems. Its water quality is pristine, it harbors abundant and diverse aquatic life, and it has long been recognized as a range-wide stronghold for two hallmark threatened fish species, the bull trout and the westslope cutthroat trout.
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.
The extensive loss of glaciers in Glacier National Park (GNP) is iconic of the global impacts of climate warming in mountain ecosystems. However, little is known about how climate change may threaten alpine stream species, especially invertebrates, persisting below disappearing snow and ice masses in GNP. Two alpine stream invertebrates – the meltwater stonefly and the glacier stonefly – have been petitioned for protection under the Endangered Species Act (ESA) due to climate-change-induced glacier loss. These cryptic species are found nowhere else in the world, but are restricted to short sections of cold streams fed by disappearing glaciers and permanent snowfields in GNP. Understanding how these species and critical alpine habitats are likely to respond to climate change is critical for conservation management and adaptation planning for freshwater systems undergoing rapid change. This project aims to investigate the current and future impacts of glacier and snow loss on the distribution, abundance, and genetic diversity of the meltwater stonefly and the glacier stonefly and other poorly known alpine aquatic invertebrates persisting below disappearing snow and ice masses in GNP.
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.
The goal of this project is to quantify the operational impacts of Hungry Horse Dam on native bull trout and westslope cutthroat trout in the upper Flathead River system, Montana.
Demographic modelling reveals a history of divergence with gene flow for a glacially tied stonefly in a changing post-Pleistocene landscape
AimClimate warming is causing extensive loss of glaciers in mountainous regions, yet our understanding of how glacial recession influences evolutionary processes and genetic diversity is limited. Linking genetic structure with the influences shaping it can improve understanding of how species respond to environmental change. Here, we used genome-...Hotaling, Scott; Muhlfeld, Clint C.; Giersch, J. Joseph; Ali, Omar; Jordan, Steve; Miller, Michael R.; Luikart, Gordon; Weisrock, David W.
A social–ecological perspective for riverscape management in the Columbia River Basin
Riverscapes are complex, landscape-scale mosaics of connected river and stream habitats embedded in diverse ecological and socioeconomic settings. Social–ecological interactions among stakeholders often complicate natural-resource conservation and management of riverscapes. The management challenges posed by the conservation and restoration of...Hand, Brian K.; Flint, Courtney G.; Frissell, Chris A.; Muhlfeld, Clint C.; Devlin, Shawn P.; Kennedy, Brian P.; Crabtree, Robert L.; McKee, W. Arthur; Luikart, Gordon; Stanford, Jack A.
Projected warming portends seasonal shifts of stream temperatures in the Crown of the Continent Ecosystem, USA and Canada
Climate warming is expected to increase stream temperatures in mountainous regions of western North America, yet the degree to which future climate change may influence seasonal patterns of stream temperature is uncertain. In this study, a spatially explicit statistical model framework was integrated with empirical stream temperature data (...Jones, Leslie A.; Muhlfeld, Clint C.; Marshall, Lucy A.
No evidence for ecological segregation protecting native trout from invasive hybridization
We appreciate the comments of Young et al. (2017) on our recent paper (Muhlfeld et al., 2017) concerning spatiotemporal dynamics of hybridization between native westslope cutthroat trout (Oncorhynchus clarkii lewisi; WCT) and introduced coastal rainbow trout (Oncorhynchus mykiss irideus; RBT). Nevertheless, we believe there is no evidence for “...Kovach, Ryan; Muhlfeld, Clint C.; Al-Chokhachy, Robert K.; Amish, Stephen J.; Kershner, Jeffrey L.; Leary, Robb F.; Lowe, Winsor H.; Luikart, Gordon; Matson, Phil; Schmetterling, David; Shepard, Bradley; Westley, Peter A. H.; Whited, Diane; Whiteley, Andrew R.; Allendorf, Fred W.
USGS integrated drought science
Project Need and OverviewDrought poses a serious threat to the resilience of human communities and ecosystems in the United States (Easterling and others, 2000). Over the past several years, many regions have experienced extreme drought conditions, fueled by prolonged periods of reduced precipitation and exceptionally warm temperatures. Extreme...Ostroff, Andrea C.; Muhlfeld, Clint C.; Lambert, Patrick M.; Booth, Nathaniel L.; Carter, Shawn L.; Stoker, Jason M.; Focazio, Michael J.
Chapter 6: Temperature
Stream temperature has direct and indirect effects on stream ecology and is critical in determining both abiotic and biotic system responses across a hierarchy of spatial and temporal scales. Temperature variation is primarily driven by solar radiation, while landscape topography, geology, and stream reach scale ecosystem processes contribute to...F. Richard Hauer; Lamberti, G.A.; Jones, Leslie A.; Muhlfeld, Clint C.; Hauer, F. Richard
Legacy introductions and climatic variation explain spatiotemporal patterns of invasive hybridization in a native trout
Hybridization between invasive and native species, a significant threat to worldwide biodiversity, is predicted to increase due to climate-induced expansions of invasive species. Long-term research and monitoring are crucial for understanding the ecological and evolutionary processes that modulate the effects of invasive species. Using a large,...Muhlfeld, Clint C.; Kovach, Ryan P.; Al-Chokhachy, Robert K.; Amish, Stephen J.; Kershner, Jeffrey L.; Leary, Robb F.; Lowe, Winsor H.; Luikart, Gordon; Matson, Phil; Schmetterling, David A.; Shepard, Bradley B.; Westley, Peter A. H.; Whited, Diane; Whiteley, Andrew R.; Allendorf, Fred W.
Suppression of invasive lake trout in an isolated backcountry lake in Glacier National Park
Fisheries managers have implemented suppression programmes to control non-native lake trout, Salvelinus namaycush (Walbaum), in several lakes throughout the western United States. This study determined the feasibility of experimentally suppressing lake trout using gillnets in an isolated backcountry lake in Glacier National Park, Montana, USA, for...Fredenberg, C. R.; Muhlfeld, Clint C.; Guy, Christopher S.; D'Angelo, Vincent S.; Downs, Christopher C.; Syslo, John M.
Climate-induced glacier and snow loss imperils alpine stream insects
Climate warming is causing rapid loss of glaciers and snowpack in mountainous regions worldwide. These changes are predicted to negatively impact the habitats of many range-restricted species, particularly endemic, mountaintop species dependent on the unique thermal and hydrologic conditions found only in glacier-fed and snowmelt-driven alpine...Giersch, J. Joseph; Hotaling, Scott; Kovach, Ryan; Jones, Leslie A.; Muhlfeld, Clint C.
Assessments of species' vulnerability to climate change: From pseudo to science
Climate change vulnerability assessments (CCVAs) are important tools to plan for and mitigate potential impacts of climate change. However, CCVAs often lack scientific rigor, which can ultimately lead to poor conservation prioritization and associated ecological and economic costs. We discuss the need to improve comparability and consistency of...Wade, Alisa A.; Hand, Brian K.; Kovach, Ryan; Muhlfeld, Clint C.; Waples, Robin S.; Luikart, Gordon
Climate, invasive species and land use drive population dynamics of a cold-water specialist
Climate change is an additional stressor in a complex suite of threats facing freshwater biodiversity, particularly for cold-water fishes. Research addressing the consequences of climate change on cold-water fish has generally focused on temperature limits defining spatial distributions, largely ignoring how climatic variation influences...Kovach, Ryan P.; Al-Chokhachy, Robert K.; Whited, Diane C.; Schmetterling, David A.; Dux, Andrew M; Muhlfeld, Clint C.
Genetic status and conservation of Westslope Cutthroat Trout in Glacier National Park
Invasive hybridization is one of the greatest threats to the persistence of Westslope Cutthroat Trout Oncorhynchus clarkii lewisi. Large protected areas, where nonhybridized populations are interconnected and express historical life history and genetic diversity, provide some of the last ecological and evolutionary strongholds for...Muhlfeld, Clint C.; D'Angelo, Vincent S.; Downs, Christopher C.; Powell, John D.; Amish, Stephen J.; Luikart, Gordon; Kovach, Ryan; Boyer, Matthew; Kalinowski, Steven T.
CDFISH: A landscape genetics program to simulate gene flow in complex riverscapes under a wide range of environmental scenarios for aquatic organisms.
MISSOULA – Gravel-bed river floodplains are some of the most ecologically important habitats in North America, according to a new study by scientists from the U.S. and Canada. Their research shows how broad valleys coming out of glaciated mountains provide highly productive and important habitat for a large diversity of aquatic, avian and terrestrial species.
Scientists have discovered that the diversity of a threatened native trout species will likely decrease due to future climate change.
The persistence of an already rare aquatic insect, the western glacier stonefly, is being imperiled by the loss of glaciers and increased stream temperatures due to climate warming in mountain ecosystems, according to a new study released in Freshwater Science.