Clint Muhlfeld, Ph.D.
I am a Research Aquatic Ecologist for the USGS Northern Rocky Mountain Science Center stationed in Glacier National Park.
Research interests
I specialize in aquatic ecology, fisheries biology, ecohydrology, and conservation biology. My research focuses on understanding the complex interactions between aquatic species and their environments to guide conservation and management of freshwater fisheries and ecosystems. I focus on how human-driven stressors—such as drought, invasive species, and habitat degradation—impact native trout, valuable recreational fisheries, and freshwater ecosystems, particularly in the northern Rocky Mountains of the United States.
My research addresses various scientific and conservation issues, including:
- Predicting the impacts of environmental changes on native trout and their freshwater habitats
- Evaluating the effects of invasive species on native fishes and ecosystem health
- Conducting ecohydrological assessments of drought and water management impacts
- Investigating life history and genetic diversity of native salmonids
- Assessing the status, threats, and conservation of threatened species to inform management needs
I am passionate about multidisciplinary science collaboration and enjoy mentoring graduate students in fisheries and freshwater ecology. I also contribute to regional, national, and international science teams focused on transboundary river management and the sustainable use of freshwater resources. My ultimate goal is to conserve native species and ecosystems 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
Science and Products
Filter Total Items: 91
A fine-scale assessment of using barriers to conserve native stream salmonids: a case study in Akokala Creek, Glacier National Park, USA
Biologists are often faced with the difficult decision in managing native salmonids of where and when to install barriers as a conservation action to prevent upstream invasion of nonnative fishes. However, fine-scale approaches to assess long-term persistence of populations within streams and watersheds chosen for isolation management are often lacking. We employed a spatially-explicit...
Authors
Clint C. Muhlfeld, Vincent S. D'Angelo, Steven T. Kalinowski, Erin L. Landguth, C.C. Downs, Joel Tohtz, Jeffrey L. Kershner
Genetic variation in westslope cutthroat trout Oncorhynchusclarkii lewisi: implications for conservation
Twenty-five populations of westslope cutthroat trout from throughout their native range were genotyped at 20 microsatellite loci to describe the genetic structure of westslope cutthroat trout. The most genetic diversity (heterozygosity, allelic richness, and private alleles) existed in populations from the Snake River drainage, while populations from the Missouri River drainage had the...
Authors
Daniel P. Drinan, Steven T. Kalinowski, Ninh V. Vu, Bradley B. Shepard, Clint C. Muhlfeld, Matthew R. Campbell
Seasonal movements of non-native lake trout in a connected lake and river system
Non-native lake trout, Salvelinus namaycush (Walbaum), threaten native salmonid populations in the western United States. Effective management of lake trout requires understanding movements within connected lake and river systems. This study determined the seasonal movements of subadult lake trout in the Flathead River upstream of Flathead Lake, Montana, USA using radio telemetry. The...
Authors
Clint C. Muhlfeld, J. Joseph Giersch, Brian Marotz
The distribution and abundance ofa nuisance native alga, Didymosphenia geminata,in streams of Glacier National Park: Climate drivers and management implications
Didymosphenia geminata (didymo) is a freshwater alga native to North America, including Glacier National Park, Montana. It has long been considered a cold-water species, but has recently spread to lower latitudes and warmer waters, and increasingly forms large blooms that cover streambeds. We used a comprehensive monitoring data set from the National Park Service (NPS) and USGS models of...
Authors
Clint C. Muhlfeld, Leslie A. Jones, E. William Schweiger, Isabel W. Ashton, Loren L. Bahls
Climate change links fate of glaciers and an endemic alpine invertebrate
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. However, little is known about the effects of climate change on alpine stream biota, especially invertebrates. Here, we show a strong linkage between regional climate change and the fundamental niche...
Authors
Clint C. Muhlfeld, J. Joseph Giersch, F. Richard Hauer, Gregory T. Pederson, Gordon Luikart, Douglas P. Peterson, Christopher C. Downs, Daniel B. Fagre
The distribution and abundance of a nuisance native alga, Didymosphen Didymosphenia geminata, in streams of Glacier National Park: Climate drivers and management implications
Didymosphenia geminata (didymo) is a freshwater alga native to North America, including Glacier National Park, Montana. It has long been considered a cold-water species, but has recently spread to lower latitudes and warmer waters, and increasingly forms large blooms that cover streambeds. We used a comprehensive monitoring data set from the National Park Service (NPS) and USGS models of...
Authors
Schweiger E. William, I.W. Ashton, Clint C. Muhlfeld, L.A. Jones, L.L. Bahls
Genetic variation in westslope cutthroat trout Oncorhynchus clarkii lewisi: Implications for conservation
Twenty-five populations of westslope cutthroat trout from throughout their native range were genotyped at 20 microsatellite loci to describe the genetic structure of westslope cutthroat trout. The most genetic diversity (heterozygosity, allelic richness, and private alleles) existed in populations from the Snake River drainage, while populations from the Missouri River drainage had the...
Authors
Daniel P. Drinan, Steven T. Kalinowski, N.V. Vu, B.B. Shepard, Clint C. Muhlfeld, M.R. Campbell
The potential influence of changing climate on the persistence of salmonids of the inland west
The Earth's climate warmed steadily during the 20th century, and mean annual air temperatures are estimated to have increased by 0.6°C (Intergovernmental Panel on Climate Change, 2007). Although many cycles of warming and cooling have occurred in the past, the most recent warming period is unique in its rate and magnitude of change (Siegenthaler and others, 2005) and in its association...
Authors
A.L. Haak, J.E. Williams, D. Isaak, A. A. Todd, Clint C. Muhlfeld, J. L. Kershner, Robert E. Gresswell, Steven W. Hostetler, H.M. Neville
Founding population size of an aquatic invasive species
Non-native species of fish threaten native fishes throughout North America, and in the Rocky Mountains, introduced populations of lake trout threaten native populations of bull trout. Effective management of lake trout and other exotic species require understanding the dynamics of invasion in order to either suppress non-native populations or to prevent their spread. In this study, we...
Authors
Steven T. Kalinowski, Clint C. Muhlfeld, Christopher S. Guy, Benjamin S. Cox
A century of climate and ecosystem change in Western Montana: What do temperature trends portend?
The physical science linking human-induced increases in greenhouse gasses to the warming of the global climate system is well established, but the implications of this warming for ecosystem processes and services at regional scales is still poorly understood. Thus, the objectives of this work were to: (1) describe rates of change in temperature averages and extremes for western Montana...
Authors
G.T. Pederson, Lisa J. Graumlich, D.B. Fagre, T. Kipfer, Clint C. Muhlfeld
Hybridization rapidly reduces fitness of a native trout in the wild
Human-mediated hybridization is a leading cause of biodiversity loss worldwide. How hybridization affects fitness and what level of hybridization is permissible pose difficult conservation questions with little empirical information to guide policy and management decisions. This is particularly true for salmonids, where widespread introgression among non-native and native taxa has often...
Authors
Clint C. Muhlfeld, Steven T. Kalinowski, Tom E McMahon, M.L. Taper, S Painter, R.F. Leary, Fred W. Allendorf
Observer error structure in bull trout redd counts in Montana streams: Implications for inference on true redd numbers
Despite the widespread use of redd counts to monitor trends in salmonid populations, few studies have evaluated the uncertainties in observed counts. We assessed the variability in redd counts for migratory bull trout Salvelinus confluentus among experienced observers in Lion and Goat creeks, which are tributaries to the Swan River, Montana. We documented substantially lower observer...
Authors
Clint C. Muhlfeld, Mark L. Taper, David F. Staples, Bradley B. Shepard
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.
Filter Total Items: 23
Science and Products
Filter Total Items: 91
A fine-scale assessment of using barriers to conserve native stream salmonids: a case study in Akokala Creek, Glacier National Park, USA
Biologists are often faced with the difficult decision in managing native salmonids of where and when to install barriers as a conservation action to prevent upstream invasion of nonnative fishes. However, fine-scale approaches to assess long-term persistence of populations within streams and watersheds chosen for isolation management are often lacking. We employed a spatially-explicit...
Authors
Clint C. Muhlfeld, Vincent S. D'Angelo, Steven T. Kalinowski, Erin L. Landguth, C.C. Downs, Joel Tohtz, Jeffrey L. Kershner
Genetic variation in westslope cutthroat trout Oncorhynchusclarkii lewisi: implications for conservation
Twenty-five populations of westslope cutthroat trout from throughout their native range were genotyped at 20 microsatellite loci to describe the genetic structure of westslope cutthroat trout. The most genetic diversity (heterozygosity, allelic richness, and private alleles) existed in populations from the Snake River drainage, while populations from the Missouri River drainage had the...
Authors
Daniel P. Drinan, Steven T. Kalinowski, Ninh V. Vu, Bradley B. Shepard, Clint C. Muhlfeld, Matthew R. Campbell
Seasonal movements of non-native lake trout in a connected lake and river system
Non-native lake trout, Salvelinus namaycush (Walbaum), threaten native salmonid populations in the western United States. Effective management of lake trout requires understanding movements within connected lake and river systems. This study determined the seasonal movements of subadult lake trout in the Flathead River upstream of Flathead Lake, Montana, USA using radio telemetry. The...
Authors
Clint C. Muhlfeld, J. Joseph Giersch, Brian Marotz
The distribution and abundance ofa nuisance native alga, Didymosphenia geminata,in streams of Glacier National Park: Climate drivers and management implications
Didymosphenia geminata (didymo) is a freshwater alga native to North America, including Glacier National Park, Montana. It has long been considered a cold-water species, but has recently spread to lower latitudes and warmer waters, and increasingly forms large blooms that cover streambeds. We used a comprehensive monitoring data set from the National Park Service (NPS) and USGS models of...
Authors
Clint C. Muhlfeld, Leslie A. Jones, E. William Schweiger, Isabel W. Ashton, Loren L. Bahls
Climate change links fate of glaciers and an endemic alpine invertebrate
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. However, little is known about the effects of climate change on alpine stream biota, especially invertebrates. Here, we show a strong linkage between regional climate change and the fundamental niche...
Authors
Clint C. Muhlfeld, J. Joseph Giersch, F. Richard Hauer, Gregory T. Pederson, Gordon Luikart, Douglas P. Peterson, Christopher C. Downs, Daniel B. Fagre
The distribution and abundance of a nuisance native alga, Didymosphen Didymosphenia geminata, in streams of Glacier National Park: Climate drivers and management implications
Didymosphenia geminata (didymo) is a freshwater alga native to North America, including Glacier National Park, Montana. It has long been considered a cold-water species, but has recently spread to lower latitudes and warmer waters, and increasingly forms large blooms that cover streambeds. We used a comprehensive monitoring data set from the National Park Service (NPS) and USGS models of...
Authors
Schweiger E. William, I.W. Ashton, Clint C. Muhlfeld, L.A. Jones, L.L. Bahls
Genetic variation in westslope cutthroat trout Oncorhynchus clarkii lewisi: Implications for conservation
Twenty-five populations of westslope cutthroat trout from throughout their native range were genotyped at 20 microsatellite loci to describe the genetic structure of westslope cutthroat trout. The most genetic diversity (heterozygosity, allelic richness, and private alleles) existed in populations from the Snake River drainage, while populations from the Missouri River drainage had the...
Authors
Daniel P. Drinan, Steven T. Kalinowski, N.V. Vu, B.B. Shepard, Clint C. Muhlfeld, M.R. Campbell
The potential influence of changing climate on the persistence of salmonids of the inland west
The Earth's climate warmed steadily during the 20th century, and mean annual air temperatures are estimated to have increased by 0.6°C (Intergovernmental Panel on Climate Change, 2007). Although many cycles of warming and cooling have occurred in the past, the most recent warming period is unique in its rate and magnitude of change (Siegenthaler and others, 2005) and in its association...
Authors
A.L. Haak, J.E. Williams, D. Isaak, A. A. Todd, Clint C. Muhlfeld, J. L. Kershner, Robert E. Gresswell, Steven W. Hostetler, H.M. Neville
Founding population size of an aquatic invasive species
Non-native species of fish threaten native fishes throughout North America, and in the Rocky Mountains, introduced populations of lake trout threaten native populations of bull trout. Effective management of lake trout and other exotic species require understanding the dynamics of invasion in order to either suppress non-native populations or to prevent their spread. In this study, we...
Authors
Steven T. Kalinowski, Clint C. Muhlfeld, Christopher S. Guy, Benjamin S. Cox
A century of climate and ecosystem change in Western Montana: What do temperature trends portend?
The physical science linking human-induced increases in greenhouse gasses to the warming of the global climate system is well established, but the implications of this warming for ecosystem processes and services at regional scales is still poorly understood. Thus, the objectives of this work were to: (1) describe rates of change in temperature averages and extremes for western Montana...
Authors
G.T. Pederson, Lisa J. Graumlich, D.B. Fagre, T. Kipfer, Clint C. Muhlfeld
Hybridization rapidly reduces fitness of a native trout in the wild
Human-mediated hybridization is a leading cause of biodiversity loss worldwide. How hybridization affects fitness and what level of hybridization is permissible pose difficult conservation questions with little empirical information to guide policy and management decisions. This is particularly true for salmonids, where widespread introgression among non-native and native taxa has often...
Authors
Clint C. Muhlfeld, Steven T. Kalinowski, Tom E McMahon, M.L. Taper, S Painter, R.F. Leary, Fred W. Allendorf
Observer error structure in bull trout redd counts in Montana streams: Implications for inference on true redd numbers
Despite the widespread use of redd counts to monitor trends in salmonid populations, few studies have evaluated the uncertainties in observed counts. We assessed the variability in redd counts for migratory bull trout Salvelinus confluentus among experienced observers in Lion and Goat creeks, which are tributaries to the Swan River, Montana. We documented substantially lower observer...
Authors
Clint C. Muhlfeld, Mark L. Taper, David F. Staples, Bradley B. Shepard
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.
Filter Total Items: 23