Jeffrey Falke, PhD
Unit Leader - Nevada Cooperative Fish and Wildlife Research Unit
Jeff's research program focuses on the impact of environmental stressors such as climate and land use change on fish population, with emphases on freshwater fish ecology, management, and conservation biology, freshwater processes and habitat dynamics, climate change impacts, landscape and spatial ecology, and invasive species biology.
Research and Teaching Interests
- Freshwater fish ecology and conservation biology;
- Ecology and evolutionary biology of salmonids;
- Landscape and spatial ecology of freshwater ecosystems;
- Climate change impacts on aquatic systems;
- Impacts of introduced species on native aquatic fauna
Multidisciplinary in nature, Jeff's research includes retrospective and forecasting analyses, is carried out at fine to broad-spatial scales, and is responsive to the needs of cooperators. Jeff's current research includes resiliency of boreal stream ecosystems to wildlife, hydrologic and juvenile salmon responses to climate change in coastal Alaska, and impacts and management of invasive Northern pike in south-central Alaska. He teaches graduate courses in research design and freshwater habitat dynamics at the University of Alaska Fairbanks.
Professional Experience
Unit Leader, Nevada Cooperative Fish and Wildlife Research Unit, 2023-
Unit Leader, Alaska Cooperative Fish and Wildlife Research Unit, 2019-2023
Assistant Unit Leader, Alaska Cooperative Fish and Wildlife Research Unit, 2012-2019
Education and Certifications
Ph D Colorado State University 2009
MS Kansas State University 2004
BS University of Missouri 2000
Science and Products
A general model of temporary aquatic habitat use: Water phenology as a life history filter
Main stem and off-channel habitat use by juvenile Chinook salmon in a sub-Arctic riverscape
An interferometric synthetic aperture radar (InSAR) habitat suitability model to identify overwinter conditions for coregonine whitefishes in Arctic lagoons
A rapid assessment method to estimate the distribution of juvenile Chinook Salmon in tributary habitats using eDNA and occupancy estimation
Influences of spawning timing, water temperature, and climatic warming on early life history phenology in western Alaska sockeye salmon
Rainbow trout movement behavior and habitat occupancy are influenced by sex and Pacific salmon presence in an Alaska river system
Thermal adaptation and phenotypic plasticity in a warming world: Insights from common garden experiments on Alaskan sockeye salmon
Groundwater declines are linked to changes in Great Plains stream fish assemblages
Global synthesis of the documented and projected effects of climate change on inland fishes
The role of density-dependent and –independent processes in spawning habitat selection by salmon in an Arctic riverscape
Fish assemblages
Seasonal movements and habitat use of Potamodromous Rainbow Trout across a complex Alaska riverscape
Science and Products
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Filter Total Items: 32
A general model of temporary aquatic habitat use: Water phenology as a life history filter
Temporary aquatic habitats are not widely appreciated fish habitat. However, fish navigate the transient waters of intertidal zones, floodplains, intermittent and ephemeral streams, lake margins, seasonally frozen lakes and streams, and anthropogenic aquatic habitats across the globe to access important resources. The selective pressures imposed by water impermanence (i.e., freezing, drying, tidalAuthorsKurt C. Heim, Jeffrey A. Falke, Thomas E. McMahon, Mark S. Wipfli, Leonardo CalleMain stem and off-channel habitat use by juvenile Chinook salmon in a sub-Arctic riverscape
Poor growth and survival in freshwater and marine environments have been implicated as responsible for Chinook salmon (Oncorhynchus tshawytscha) declines across Alaska.Lateral connectivity of river main stems with off-channel habitats may play an integral role in sustaining Alaskan salmonid populations because off-channel habitats commonly provide greater growth opportunities than main stem habitaAuthorsBrock M. Huntsman, Jeffrey A. FalkeAn interferometric synthetic aperture radar (InSAR) habitat suitability model to identify overwinter conditions for coregonine whitefishes in Arctic lagoons
Lagoons provide critical habitats for many fishes, including coregonine whitefishes, which are a mainstay in many subsistence fisheries of rural communities in Arctic Alaska. Despite their importance, little is known about the overwintering habits of whitefishes in Arctic Alaska due to the challenges associated with sampling during winter. We developed a habitat suitability (HS) model to understanAuthorsMarguerite Tibbles, Jeffrey A. Falke, Andrew R. Mahoney, Martin D. Robards, Andrew C. SeitzA rapid assessment method to estimate the distribution of juvenile Chinook Salmon in tributary habitats using eDNA and occupancy estimation
Identification and protection of water bodies used by anadromous species are critical in light of increasing threats to fish populations, yet often challenging given budgetary and logistical limitations. Noninvasive, rapid‐assessment, sampling techniques may reduce costs and effort while increasing species detection efficiencies. We used an intrinsic potential (IP) habitat model to identify high‐qAuthorsA. Matter, Jeffrey A. Falke, J. Andres López, James W. SavereideInfluences of spawning timing, water temperature, and climatic warming on early life history phenology in western Alaska sockeye salmon
We applied an empirical model to predict hatching and emergence timing for 25 western Alaska sockeye salmon (Oncorhynchus nerka) populations in four lake-nursery systems to explore current patterns and potential responses of early life history phenology to warming water temperatures. Given experienced temperature regimes during development, we predicted hatching to occur in as few as 58 d to as maAuthorsMorgan M. Sparks, Jeffrey A. Falke, Thomas P. Quinn, Milo D. Adkison, Daniel E. Schindler, Krista K. Bartz, Daniel B. Young, Peter A. H. WestleyRainbow trout movement behavior and habitat occupancy are influenced by sex and Pacific salmon presence in an Alaska river system
We used spatially continuous field-measured and remotely-sensed aquatic habitat characteristics paired with weekly ground-based telemetry tracking and snorkel surveys to describe movements and habitat occupancy of adult rainbow trout (N = 82) in a runoff-fed, salmon-influenced southcentral Alaska river system. We found that during the ice-free feeding season (June through September) rainbow troutAuthorsKevin M. Fraley, Jeffrey A. Falke, Megan V. McPhee, Anupma PrakashThermal adaptation and phenotypic plasticity in a warming world: Insights from common garden experiments on Alaskan sockeye salmon
An important unresolved question is how populations of coldwater-dependent fishes will respond to rapidly warming water temperatures. For example, the culturally and economically important group, Pacific salmon (Oncorhynchus spp.), experience site-specific thermal regimes during early development that could be disrupted by warming. To test for thermal local adaptation and heritable phenotypic plasAuthorsMorgan M. Sparks, Peter A. H. Westley, Jeffrey A. Falke, Thomas P. QuinnGroundwater declines are linked to changes in Great Plains stream fish assemblages
Groundwater pumping for agriculture is a major driver causing declines of global freshwater ecosystems, yet the ecological consequences for stream fish assemblages are rarely quantified. We combined retrospective (1950–2010) and prospective (2011–2060) modeling approaches within a multiscale framework to predict change in Great Plains stream fish assemblages associated with groundwater pumping froAuthorsJoshuah S. Prekins, Keith B. Gido, Jeffrey A. Falke, Kurt D. Fausch, Harry Crockett, Eric R. Johnson, John SandersonGlobal synthesis of the documented and projected effects of climate change on inland fishes
Although climate change is an important factor affecting inland fishes globally, a comprehensive review of how climate change has impacted and will continue to impact inland fishes worldwide does not currently exist. We conducted an extensive, systematic primary literature review to identify English-language, peer-reviewed journal publications with projected and documented examples of climate chanAuthorsBonnie Myers, Abigail Lynch, David B. Bunnell, Cindy Chu, Jeffrey A. Falke, Ryan Kovach, Trevor J. Krabbenhoft, Thomas J. Kwak, Craig P. PaukertThe role of density-dependent and –independent processes in spawning habitat selection by salmon in an Arctic riverscape
Density-dependent (DD) and density-independent (DI) habitat selection is strongly linked to a species’ evolutionary history. Determining the relative importance of each is necessary because declining populations are not always the result of altered DI mechanisms but can often be the result of DD via a reduced carrying capacity. We developed spatially and temporally explicit models throughout the CAuthorsBrock M. Huntsman, Jeffrey A. Falke, James W. Savereide, Katrina E. BennettFish assemblages
Methods to sample fishes in stream ecosystems and to analyze the raw data, focusing primarily on assemblage-level (all fish species combined) analyses, are presented in this chapter. We begin with guidance on sample site selection, permitting for fish collection, and information-gathering steps to be completed prior to conducting fieldwork. Basic sampling methods (visual surveying, electrofishing,AuthorsDaniel J. McGarvey, Jeffrey A. Falke, Hiram W. Li, Judith LiSeasonal movements and habitat use of Potamodromous Rainbow Trout across a complex Alaska riverscape
Potamodromous Rainbow Trout Oncorhynchus mykiss are an important ecological and recreational resource in freshwater ecosystems of Alaska, and increased human development, hydroelectric projects, and reduced escapement of Chinook Salmon Oncorhynchus tshawytscha may threaten their populations. We used aerial and on-the-ground telemetry tracking, a digital landscape model, and resource selection funcAuthorsKevin M. Fraley, Jeffrey A. Falke, Richard Yanusz, Sam S. Ivey - Software