Clint Muhlfeld, Ph.D.
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.
Research interests
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
Seasonal movements of non-native lake trout in a connected lake and river system
The distribution and abundance ofa nuisance native alga, Didymosphenia geminata,in streams of Glacier National Park: Climate drivers and management implications
Climate change links fate of glaciers and an endemic alpine invertebrate
Genetic variation in westslope cutthroat trout Oncorhynchus clarkii lewisi: Implications for conservation
The distribution and abundance of a nuisance native alga, Didymosphen Didymosphenia geminata, in streams of Glacier National Park: Climate drivers and management implications
The potential influence of changing climate on the persistence of salmonids of the inland west
Founding population size of an aquatic invasive species
A century of climate and ecosystem change in Western Montana: What do temperature trends portend?
Hybridization rapidly reduces fitness of a native trout in the wild
Observer error structure in bull trout redd counts in Montana streams: Implications for inference on true redd numbers
Seasonal movement and habitat use by sub-adult bull trout in the upper Flathead River system, Montana
Spread of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, Oncorhynchus mykiss
Non-USGS Publications**
**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
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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 spatiotemporAuthorsClint C. Muhlfeld, J. Joseph Giersch, Brian MarotzThe 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 stream teAuthorsClint C. Muhlfeld, Leslie A. Jones, E. William Schweiger, Isabel W. Ashton, Loren L. BahlsClimate 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 of a rare aAuthorsClint C. Muhlfeld, J. Joseph Giersch, F. Richard Hauer, Gregory T. Pederson, Gordon Luikart, Douglas P. Peterson, Christopher C. Downs, Daniel B. FagreGenetic 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 least. NeigAuthorsD.P. Drinan, S.T. Kalinowski, N.V. Vu, B.B. Shepard, C.C. Muhlfeld, M. R. CampbellThe 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 stream teAuthorsSchweiger E. William, I.W. Ashton, C.C. Muhlfeld, L.A. Jones, L.L. BahlsThe 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 with anthroAuthorsA.L. Haak, J.E. Williams, D. Isaak, A. Todd, C.C. Muhlfeld, J. L. Kershner, R. E. Gresswell, S. W. Hostetler, H.M. NevilleFounding 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 used microsaAuthorsSteven T. Kalinowski, Clint C. Muhlfeld, Christopher S. Guy, Benjamin CoxA 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, a region cAuthorsG.T. Pederson, L.J. Graumlich, D.B. Fagre, T. Kipfer, C.C. MuhlfeldHybridization 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 created hyAuthorsC.C. Muhlfeld, S.T. Kalinowski, T.E. McMahon, M.L. Taper, S. Painter, R.F. Leary, F.W. AllendorfObserver 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 variability iAuthorsClint C. Muhlfeld, Mark L. Taper, David F. Staples, Bradley B. ShepardSeasonal 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 river systAuthorsClint C. Muhlfeld, Brian MarotzSpread 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 determinedAuthorsNathaniel P. Hitt, Christopher A. Frissell, Clint C. Muhlfeld, Fred W. AllendorfNon-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.
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*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