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 United States and Canada.
My research spans a range of scientific and conservation issues from examining 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 freshwater ecology and conservation biology projects. 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.
Education and Certifications
Ph.D. 2008. Fish and Wildlife Biology, Montana State University, Bozeman
M.S. 1999. Fishery Resources, University of Idaho, Moscow
B.S. 1994. Aquatic Biology, University of Montana, Missoula; University of Maine, Orono
Affiliations and Memberships*
Flathead Lake Biological Station, University of Montana
Science and Products
Climate change links fate of glaciers and rare alpine stream invertebrates in Glacier National Park
Assessing the Vulnerability of Native Trout in the Northern Rockies: Linking Science and Management for Climate Adaptation
Integrated Ecohydrological Science in the Northern Rocky Mountains — the variability of water availability and the effects on ecosystems
Experimental suppression of invasive lake trout: Implications for conservation of imperiled bull trout in Glacier National Park
Predicting Climate-Induced Expansions of Invasive Fish in the Pacific Northwest: Implications for Climate Adaptation of Native Salmon and Trout
Understanding Climate Impacts on Native and Invasive Fish for Conservation, Management, and Economic Goals in the Northern Rockies
Science in Glacier National Park
Western Waters Invasive Species and Disease Research Program
Climate Change Impacts on Invasive Species in the Northwest: A Synthesis and Path Forward
Translocation of imperiled fishes: Conservation introduction of threatened bull trout in Glacier National Park
Predicting climate change impacts on river ecosystems and salmonids across the Pacific Northwest: Combining vulnerability modeling, landscape genomics, and economic evaluations for conservation
Genetic status and distribution of native westslope cutthroat trout in Glacier National Park
Glacier National Park alpine aquatic invertebrates, 2011-2013
High dispersal rates in hybrids drive expansion of maladaptive hybridization
Rapid SNP genotyping, sex identification, and hybrid-detection in threatened bull trout
Socioeconomic resilience to climatic extremes in a freshwater fishery
Stream size, temperature, and density explain body sizes of freshwater salmonids across a range of climate conditions
Stoneflies in the genus Lednia (Plecoptera: Nemouridae): Sentinels of climate change impacts on mountain stream biodiversity
Climate change and expanding invasive species drive widespread declines of native trout in the northern Rocky Mountains, USA
Species invasion progressively disrupts the trophic structure of native food webs
Testing a generalizable machine learning workflow for aquatic invasive species on Rainbow Trout (Oncorhynchus mykiss) in northwest Montana
Influence of water temperature and biotic interactions on the distribution of westslope cutthroat trout (Oncorhynchus clarkii lewisi) in a population stronghold under climate change
Hybridization alters growth and migratory life-history expression of native trout
An interactive data visualization framework for exploring geospatial environmental datasets and model predictions
Specialized meltwater biodiversity persists despite widespread deglaciation
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 21
Climate change links fate of glaciers and rare alpine stream invertebrates in Glacier National ParkThe 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 – are...
Assessing the Vulnerability of Native Trout in the Northern Rockies: Linking Science and Management for Climate AdaptationTrout are one of the most culturally, economically, and ecologically important groups of freshwater fishes in the Rocky Mountain region. However, human impacts and climate change are significantly altering freshwater ecosystems that support native trout species. Despite their broad importance, many of the region’s trout populations are threatened and some require immediate conservation efforts to
Integrated Ecohydrological Science in the Northern Rocky Mountains — the variability of water availability and the effects on ecosystemsOur primary goal is to better understand and characterize how stream environments and the ecosystems they support are influenced by climate change and drought in the Northern Rocky Mountains.
Experimental suppression of invasive lake trout: Implications for conservation of imperiled bull trout in Glacier National ParkAfter 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...
Predicting Climate-Induced Expansions of Invasive Fish in the Pacific Northwest: Implications for Climate Adaptation of Native Salmon and TroutThe headwaters of the Columbia River Basin in the Northern Rocky Mountains region is widely recognized as a stronghold for native fish, containing some of the last remaining connected cold-water habitats for species such as the threatened bull trout and native westslope cutthroat trout. However, as temperatures rise, non-native invasive fish species could be poised to prosper in the region as cond
Understanding Climate Impacts on Native and Invasive Fish for Conservation, Management, and Economic Goals in the Northern RockiesAs the origin of three major basins that drain the Columbia, Missouri, and Saskatchewan rivers, Montana is the hydrologic apex for North America. The Northern Rocky Mountain region is home to some of the last remaining interconnected habitats for many native fishes, including the threatened bull trout and native westslope cutthroat trout. The Northern Rockies are also experiencing rapidly changing
Science in Glacier National ParkGlacier National Park (GNP) is considered a stronghold for a large diversity of plant and animal species and harbors some of the last remaining populations of threatened and endangered species such as grizzly bear and bull trout, as well as non threatened keystone species such as bighorn sheep and black bear. The mountain ecosystems of GNP that support these species are dynamic and influenced by...
Western Waters Invasive Species and Disease Research ProgramResearchers at the Northern Rocky Mountain Science Center's Western Waters Invasive Species and Disease Research Program work extensively with federal, state, tribal, regional, and local partners to deliver science to improve early detection and prevention of invasive species and disease; understand complex interactions that promote invasive species and disease, and their impacts (and associated...
Climate Change Impacts on Invasive Species in the Northwest: A Synthesis and Path ForwardInvasive species have increasingly severe consequences for ecosystems and human communities alike. The ecological impacts of invasive species are often irreversible, and include the loss of native species and the spread of disease. Implications for human communities include damaged water transportation systems, reduced crop yields, reduced forage quality for livestock, and widespread tree death -
Translocation of imperiled fishes: Conservation introduction of threatened bull trout in Glacier National ParkThere 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...
Predicting climate change impacts on river ecosystems and salmonids across the Pacific Northwest: Combining vulnerability modeling, landscape genomics, and economic evaluations for conservationSalmonids – 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...
Genetic status and distribution of native westslope cutthroat trout in Glacier National ParkAfter 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...
Glacier National Park alpine aquatic invertebrates, 2011-2013This data release incorporates high-resolution geospatial and biological data and accompanies a peer-reviewed manuscript "Specialized meltwater biodiversity persists despite widespread deglaciation". In this study, we tested the prediction that glacier retreat reduces biodiversity in mountain ecosystems through the loss of uniquely adapted meltwater stream species in Glacier National Park, USA. Th
Filter Total Items: 87
High dispersal rates in hybrids drive expansion of maladaptive hybridizationHybridization between native and invasive species, a major cause of biodiversity loss, can spread rapidly even when hybrids have reduced fitness. This paradox suggests that hybrids have greater dispersal rates than non-hybridized individuals, yet this mechanism has not been empirically tested in animal populations. Here, we test if non-native genetic introgression increases reproductive dispersalAuthorsSamuel Bourret, Ryan P. Kovach, Timothy Joseph Cline, Jeffrey Strait, Clint C. Muhlfeld
Rapid SNP genotyping, sex identification, and hybrid-detection in threatened bull troutWe developed new bull trout genetic markers using Restriction-site Associated DNA sequencing (RAD-seq) to improve our ability to address questions important for their conservation and management. Samples from across the species range were sequenced and 5020 high quality single nucleotide polymorphism (SNP) loci were discovered, including hundreds with high heterozygosity (H > 0.30). We developed 6AuthorsStephen J. Amish, Shana Bernall, Patrick W. DeHaan, Michael A. Miller, Sean M. O'Rourke, Matthew Boyer, Clint C. Muhlfeld, Angela Lodmell, Robb F. Leary, Gordon Luikart
Socioeconomic resilience to climatic extremes in a freshwater fisheryHeterogeneity is a central feature of ecosystem resilience, but how this translates to socioeconomic resilience depends on people’s ability to track shifting resources in space and time. Here, we quantify how climatic extremes have influenced how people (fishers) track economically valuable ecosystem services (fishing opportunities) across a range of spatial scales in rivers of the northern RockyAuthorsTimothy Joseph Cline, Clint C. Muhlfeld, Ryan P. Kovach, Robert Al-Chokhachy, David Schmetterling, Diane Whited, Abigail Lynch
Stream size, temperature, and density explain body sizes of freshwater salmonids across a range of climate conditionsClimate change and anthropogenic activities are altering the body sizes of fishes, yet our understanding of factors influencing body size for many taxa remains incomplete. We evaluated the relationships between climate, environmental, and landscape attributes and the body size of different taxa of freshwater trout (Salmonidae) in the USA. Hierarchical spatial modeling across a gradient of habitatsAuthorsRobert K. Al-Chokhachy, Benjamin Letcher, Clint C. Muhlfeld, Jason Dunham, Timothy Joseph Cline, Nathaniel P. Hitt, James Roberts, David Schmetterling
Stoneflies in the genus Lednia (Plecoptera: Nemouridae): Sentinels of climate change impacts on mountain stream biodiversityRapid recession of glaciers and snowfields is threatening the habitats of cold-water biodiversity worldwide. In many ice-sourced headwaters of western North America, stoneflies in the genus Lednia (Plecoptera: Nemouridae) are a prominent member of the invertebrate community. With a broad distribution in mountain streams and close ties to declining glacier cover, Lednia has emerged as a sentinel ofAuthorsMatthew D. Green, Lusha M. Tronstad, J. Joseph Giersch, Alisha A. Shah, Candace E. Fallon, Emilie Blevins, Taylor Kai, Clint C. Muhlfeld, Debra S. Finn, Scott Hotaling
Climate change and expanding invasive species drive widespread declines of native trout in the northern Rocky Mountains, USAClimate change and invasive species are major threats to native biodiversity, but few empirical studies have examined their combined effects at large spatial and temporal scales. Using 21,917 surveys collected over 30 years, we quantified the impacts of climate change on the past and future distributions of five interacting native and invasive trout species throughout the northern Rocky Mountains,AuthorsDonovan A. Bell, Ryan P. Kovach, Clint C. Muhlfeld, Robert Al-Chokhachy, Timothy Joseph Cline, Diane C. Whited, David Schmetterling, Paul M Lukacs, Andrew R. Whiteley
Species invasion progressively disrupts the trophic structure of native food websSpecies invasions can have substantial impacts on native species and ecosystems, with important consequences for biodiversity. How these disturbances drive changes in the trophic structure of native food webs through time is poorly understood. Here, we quantify trophic disruption in freshwater food webs to invasion by an apex fish predator, lake trout, using an extensive stable isotope dataset acrAuthorsCharles Wainright, Clint C. Muhlfeld, James J. Elser, Samuel Bourret, Shawn P. Devlin
Testing a generalizable machine learning workflow for aquatic invasive species on Rainbow Trout (Oncorhynchus mykiss) in northwest MontanaBiological invasions are accelerating worldwide, causing major ecological and economic impacts in aquatic ecosystems. The urgent decision-making needs of invasive species managers can be better met by the integration of biodiversity big data with large-domain models and data-driven products. Remotely sensed data products can be combined with existing invasive species occurrence data via machine leAuthorsSean C. Carter, Charles B. van Rees, Brian K. Hand, Clint C. Muhlfeld, Gordon Luikart, John S Kimball
Influence of water temperature and biotic interactions on the distribution of westslope cutthroat trout (Oncorhynchus clarkii lewisi) in a population stronghold under climate changeClimate warming is expected to have substantial impacts on native trout across the Rocky Mountains, but there is little understanding of how these changes affect future distributions of co-occurring native fishes within population strongholds. We used mixed-effects logistic regression to investigate the role of abiotic (e.g., temperature) and biotic factors (bull trout presence, Salvelinus conflueAuthorsKadie Heinle, Lisa A Eby, Clint C. Muhlfeld, Amber Steed, Leslie Jones, Vincent S. D'Angelo, Andrew R. Whiteley, Mark Hubblewhite
Hybridization alters growth and migratory life-history expression of native troutHuman-mediated hybridization threatens many native species, but the effects of introgressive hybridization on life-history expression are rarely quantified, especially in vertebrates. We quantified the effects of non-native rainbow trout admixture on important life-history traits including growth and partial migration behavior in three populations of westslope cutthroat trout over five years. RainAuthorsJeffrey Strait, Lisa A Eby, Ryan P. Kovach, Clint C. Muhlfeld, Matthew Boyer, Stephen J. Amish, Seth Smith, Winsor H. Lowe, Gordon Luikart
An interactive data visualization framework for exploring geospatial environmental datasets and model predictionsWith the rise of large-scale environmental models comes new challenges for how we best utilize this information in research, management and decision making. Interactive data visualizations can make large and complex datasets easier to access and explore, which can lead to knowledge discovery, hypothesis formation and improved understanding. Here, we present a web-based interactive data visualizatiAuthorsJeffrey D Walker, Benjamin Letcher, Kirk D. Rodgers, Clint C. Muhlfeld, Vincent S. D'Angelo
Specialized meltwater biodiversity persists despite widespread deglaciationGlaciers are important drivers of environmental heterogeneity and biological diversity across mountain landscapes. Worldwide, glaciers are receding rapidly due to climate change, with important consequences for biodiversity in mountain ecosystems. However, the effects of glacier loss on biodiversity have never been quantified across a mountainous region, primarily due to a lack of adequate data atAuthorsClint C. Muhlfeld, Timothy Joseph Cline, J. Joseph Giersch, Erich Peitzsch, Caitlyn Florentine, Dean Jacobsen, Scott Hotaling
Non-USGS Publications**Muhlfeld, Clint C., Thomas E. McMahon, and Durae Belcer. 2009. Spatial and temporal dynamics of spawning between native westslope cutthroat trout (Oncorhynchus clarkii lewisi), introduced rainbow trout (O. mykiss), and their hybrids. Canadian Journal of Fisheries and Aquatic Sciences 66:1153-1168.Muhlfeld, Clint C., Thomas E. McMahon, Matthew C. Boyer, and Robert E. Gresswell. 2009. Local-habitat, watershed, and biotic factors in the spread of hybridization between native westslope cutthroat trout and introduced rainbow trout. Transactions of the American Fisheries Society 138:1036-1051.Boyer, Matthew C., Clint C. Muhlfeld, and Fred Allendorf. 2008. Rainbow trout invasion and the spread of hybridization with westslope cutthroat trout. Canadian Journal of Fisheries and Aquatic Sciences 65:658-669.Muhlfeld, Clint C., David H. Bennett, Kirk Steinhorst, Brian Marotz, and Matthew C. Boyer. 2008. Using bioenergetics modeling to estimate consumption of native juvenile salmonids by nonnative northern pike in the upper Flathead River system, Montana. North American Journal of Fisheries Management 28:636-648.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government