Clint Muhlfeld, Ph.D.
I am a Research Aquatic Ecologist at the USGS Northern Rocky Mountain Science Center (NOROCK) in West Glacier, Montana. I currently serve as the Acting Center Director of NOROCK in Bozeman, Montana.
Research interests
As a Research Aquatic Ecologist, I study the ecology, evolution, and conservation of freshwater species and ecosystems. My research examines how climate variability, hydrologic change, biological invasions, and habitat alteration influence freshwater biodiversity and ecosystem processes, with particular expertise in cold-water biota. I have led ecological and evolutionary studies across freshwater systems ranging from glacier-fed mountain streams and large river networks to lakes, as well as regional and global assessments of trout and char. My research combines long-term ecological studies, field research, genetics, and quantitative modeling and draws on multiple disciplines, including ecology, fisheries science, genetics, and hydrology.
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: 24
Filter Total Items: 96
The potential influence of changing climate on the persistence of salmonids of the inland west 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. Todd, C.C. Muhlfeld, J. L. Kershner, R. E. Gresswell, S. W. Hostetler, H.M. Neville
Founding population size of an aquatic invasive species 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 Cox
A century of climate and ecosystem change in Western Montana: What do temperature trends portend? 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, L.J. Graumlich, D.B. Fagre, T. Kipfer, C.C. Muhlfeld
Hybridization rapidly reduces fitness of a native trout in the wild 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
C.C. Muhlfeld, S.T. Kalinowski, T.E. McMahon, M.L. Taper, S. Painter, R.F. Leary, F.W. Allendorf
Observer error structure in bull trout redd counts in Montana streams: Implications for inference on true redd numbers 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
Seasonal movement and habitat use by sub-adult bull trout in the upper Flathead River system, Montana Seasonal movement and habitat use by sub-adult bull trout in the upper Flathead River system, Montana
Despite the importance of large-scale habitat connectivity to the threatened bull trout Salvelinus confluentus, little is known about the life history characteristics and processes influencing natural dispersal of migratory populations. We used radiotelemetry to investigate the seasonal movements and habitat use by subadult bull trout (i.e., fish that emigrated from natal streams to the...
Authors
Clint C. Muhlfeld, Brian Marotz
Spread of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, Oncorhynchus mykiss Spread of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, Oncorhynchus mykiss
We examined spatial and temporal patterns of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, O. mykiss, in streams of the Flathead River system in Montana, U.S.A. We detected hybridization in 24 of 42 sites sampled from 1998 to 2001. We found new Oncorhynchus mykiss introgression in seven of 11 sample populations that were...
Authors
Nathaniel P. Hitt, Christopher A. Frissell, Clint C. Muhlfeld, Fred W. Allendorf
Winter diel habitat use and movement by subadult bull trout in the upper Flathead River, Montana Winter diel habitat use and movement by subadult bull trout in the upper Flathead River, Montana
We evaluated the diel habitat use and movement of subadult bull trout Salvelinus confluentus by use of radiotelemetry during winter in the upper Flathead River, Montana. Of the 13 monitored bull trout, 12 (92%) made at least one diel movement to other habitat locations during their respective day–night tracking surveys and moved an average of 73% of the time. The median distance moved...
Authors
Clint C. Muhlfeld, Steve Glutting, Rick Hunt, Durae Daniels, Brian Marotz
Genetic structure of Columbia River redband trout populations in the Kootenai River drainage, Montana, revealed by microsatellite and allozyme loci Genetic structure of Columbia River redband trout populations in the Kootenai River drainage, Montana, revealed by microsatellite and allozyme loci
We describe the genetic divergence among 10 populations of redband trout Oncorhynchus mykiss gairdneri from the upper Columbia River drainage. Resident redband trout from two watersheds in the Kootenai River drainage and hatchery stocks of migratory Kamloops redband trout from Kootenay Lake, British Columbia, were analyzed using allele frequency data from microsatellite and allozyme loci...
Authors
Kathy L. Knudsen, Clint C. Muhlfeld, George K. Sage, Robb F. Leary
Spawning characteristics of redband trout in a headwater stream in Montana Spawning characteristics of redband trout in a headwater stream in Montana
I investigated the spawning characteristics of redband trout Oncorhynchus mykiss gairdneri (a rainbow trout subspecies) during the spring of 1998 in Basin Creek, a third-order headwater stream located in the Kootenai River drainage in northwestern Montana. I examined the timing of spawning as related to discharge and water temperature and analyzed microhabitat selection of 30 completed...
Authors
Clint C. Muhlfeld
Fall and winter habitat use and movement by Columbia River redband trout in a small stream in Montana Fall and winter habitat use and movement by Columbia River redband trout in a small stream in Montana
We used radiotelemetry to quantify the movements and habitat use of resident adult Columbia River redband trout Oncorhynchus mykiss gairdneri (hereafter, redband trout) from October to December 1997 in South Fork Callahan Creek, a third‐order tributary to Callahan Creek in the Kootenai River drainage in northwestern Montana. All redband trout (N = 23) were consistently relocated in a...
Authors
Clint C. Muhlfeld, David H. Bennett, B. Marotz
Summer habitat use by Columbia River redband trout in the Kootenai River drainage, Montana Summer habitat use by Columbia River redband trout in the Kootenai River drainage, Montana
The reported decline in the abundance, distribution, and genetic diversity of Columbia River redband trout Oncorhynchus mykiss gairdneri (a rainbow trout subspecies) has prompted fisheries managers to investigate their habitat requirements, identify critical habitat, and develop effective conservation and recovery programs. We analyzed the microhabitat, mesohabitat, and macrohabitat use...
Authors
Clint C. Muhlfeld, David H. Bennett
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.
Science and Products
Filter Total Items: 24
Filter Total Items: 96
The potential influence of changing climate on the persistence of salmonids of the inland west 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. Todd, C.C. Muhlfeld, J. L. Kershner, R. E. Gresswell, S. W. Hostetler, H.M. Neville
Founding population size of an aquatic invasive species 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 Cox
A century of climate and ecosystem change in Western Montana: What do temperature trends portend? 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, L.J. Graumlich, D.B. Fagre, T. Kipfer, C.C. Muhlfeld
Hybridization rapidly reduces fitness of a native trout in the wild 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
C.C. Muhlfeld, S.T. Kalinowski, T.E. McMahon, M.L. Taper, S. Painter, R.F. Leary, F.W. Allendorf
Observer error structure in bull trout redd counts in Montana streams: Implications for inference on true redd numbers 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
Seasonal movement and habitat use by sub-adult bull trout in the upper Flathead River system, Montana Seasonal movement and habitat use by sub-adult bull trout in the upper Flathead River system, Montana
Despite the importance of large-scale habitat connectivity to the threatened bull trout Salvelinus confluentus, little is known about the life history characteristics and processes influencing natural dispersal of migratory populations. We used radiotelemetry to investigate the seasonal movements and habitat use by subadult bull trout (i.e., fish that emigrated from natal streams to the...
Authors
Clint C. Muhlfeld, Brian Marotz
Spread of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, Oncorhynchus mykiss Spread of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, Oncorhynchus mykiss
We examined spatial and temporal patterns of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, O. mykiss, in streams of the Flathead River system in Montana, U.S.A. We detected hybridization in 24 of 42 sites sampled from 1998 to 2001. We found new Oncorhynchus mykiss introgression in seven of 11 sample populations that were...
Authors
Nathaniel P. Hitt, Christopher A. Frissell, Clint C. Muhlfeld, Fred W. Allendorf
Winter diel habitat use and movement by subadult bull trout in the upper Flathead River, Montana Winter diel habitat use and movement by subadult bull trout in the upper Flathead River, Montana
We evaluated the diel habitat use and movement of subadult bull trout Salvelinus confluentus by use of radiotelemetry during winter in the upper Flathead River, Montana. Of the 13 monitored bull trout, 12 (92%) made at least one diel movement to other habitat locations during their respective day–night tracking surveys and moved an average of 73% of the time. The median distance moved...
Authors
Clint C. Muhlfeld, Steve Glutting, Rick Hunt, Durae Daniels, Brian Marotz
Genetic structure of Columbia River redband trout populations in the Kootenai River drainage, Montana, revealed by microsatellite and allozyme loci Genetic structure of Columbia River redband trout populations in the Kootenai River drainage, Montana, revealed by microsatellite and allozyme loci
We describe the genetic divergence among 10 populations of redband trout Oncorhynchus mykiss gairdneri from the upper Columbia River drainage. Resident redband trout from two watersheds in the Kootenai River drainage and hatchery stocks of migratory Kamloops redband trout from Kootenay Lake, British Columbia, were analyzed using allele frequency data from microsatellite and allozyme loci...
Authors
Kathy L. Knudsen, Clint C. Muhlfeld, George K. Sage, Robb F. Leary
Spawning characteristics of redband trout in a headwater stream in Montana Spawning characteristics of redband trout in a headwater stream in Montana
I investigated the spawning characteristics of redband trout Oncorhynchus mykiss gairdneri (a rainbow trout subspecies) during the spring of 1998 in Basin Creek, a third-order headwater stream located in the Kootenai River drainage in northwestern Montana. I examined the timing of spawning as related to discharge and water temperature and analyzed microhabitat selection of 30 completed...
Authors
Clint C. Muhlfeld
Fall and winter habitat use and movement by Columbia River redband trout in a small stream in Montana Fall and winter habitat use and movement by Columbia River redband trout in a small stream in Montana
We used radiotelemetry to quantify the movements and habitat use of resident adult Columbia River redband trout Oncorhynchus mykiss gairdneri (hereafter, redband trout) from October to December 1997 in South Fork Callahan Creek, a third‐order tributary to Callahan Creek in the Kootenai River drainage in northwestern Montana. All redband trout (N = 23) were consistently relocated in a...
Authors
Clint C. Muhlfeld, David H. Bennett, B. Marotz
Summer habitat use by Columbia River redband trout in the Kootenai River drainage, Montana Summer habitat use by Columbia River redband trout in the Kootenai River drainage, Montana
The reported decline in the abundance, distribution, and genetic diversity of Columbia River redband trout Oncorhynchus mykiss gairdneri (a rainbow trout subspecies) has prompted fisheries managers to investigate their habitat requirements, identify critical habitat, and develop effective conservation and recovery programs. We analyzed the microhabitat, mesohabitat, and macrohabitat use...
Authors
Clint C. Muhlfeld, David H. Bennett
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.