Jeffrey Falke, PhD
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, Alaska Cooperative Fish and Wildlife Research Unit, 2019-
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
Coral Response to Land-to-Ocean Freshwater Flux: A Ridge-to-Reef Perspective
Webinar: Aquatic Ecosystem Vulnerability to Fire and Climate Change in Alaskan Boreal Forests
Stream hydrology and a pulse subsidy shape patterns of fish foraging
Data describing vulnerability of Pacific salmon to invasion of northern pike (Esox lucius) in southcentral Alaska, 2017-2019
Fish and Climate Change (FiCli) Database: Informing climate change adaptation and management actions for freshwater fishes
Reducing uncertainty in climate change responses of inland fishes: A decision-path approach
Climate change effects on North American fish and fisheries to inform adaptation strategies
Assessing potential stock structure of adult Coho Salmon in a small Alaska watershed: Quantifying run timing, spawning locations, and holding areas with radiotelemetry
High-resolution remote sensing and multistate occupancy estimation identify drivers of spawning site selection in fall chum salmon (Oncorhynchus keta) across a sub-Arctic riverscape
Vulnerability of Pacific salmon to invasion of northern pike (Esox lucius) in Southcentral Alaska
Determinants of gray wolf (Canis lupus) sightings in Denali National Park
FiCli, the Fish and Climate Change Database, informs climate adaptation and management for freshwater fishes
Thermal diversity of salmon streams in the Matanuska-Susitna Basin, Alaska
A classification of streamflow patterns across the coastal Gulf of Alaska
Energetic status of Alaskan Chinook Salmon: Interpopulation comparisons and predictive modeling using bioelectrical impedance analysis
Climatic variation drives growth potential of juvenile Chinook Salmon (Oncorhynchus tshawytscha) along a sub-Arctic boreal riverscape
Energetic status and bioelectrical impedance modeling of Arctic grayling Thymallus arcticus in interior Alaska Rivers
Code to Support Hypoxia vulnerability in the salmon watersheds of Southeast Alaska
Science and Products
- Science
Coral Response to Land-to-Ocean Freshwater Flux: A Ridge-to-Reef Perspective
Assessments that incorporate areas from land-to-ocean, or “ridge-to-reef", are critical to examine how land-use practices are altering stream discharge and nearshore marine health and productivity. Stream systems in both Alaska and Hawaiʻi are expected to experience changes in water quality associated with changing environmental conditions and increased human-use. Watershed systems throughout theWebinar: Aquatic Ecosystem Vulnerability to Fire and Climate Change in Alaskan Boreal Forests
View this webinar for more information about conservation efforts surrounding aquatic habitats in boreal Alaska. - Data
Stream hydrology and a pulse subsidy shape patterns of fish foraging
Pulsed subsidy events create ephemeral fluxes of hyper-abundant resources that can shape annual patterns of consumption and growth for recipient consumers. However, environmental conditions strongly affect local resource availability for much of the year, and can heavily impact consumer foraging and growth patterns prior to pulsed subsidy events. Thus, a consumer’s capacity to exploit pulse subsidData describing vulnerability of Pacific salmon to invasion of northern pike (Esox lucius) in southcentral Alaska, 2017-2019
The shapefile contains the data necessary to recreate the analyses used in Jalbert et al., in review, Vulnerability of Pacific salmon to invasion of northern pike (Esox lucius) in southcentral Alaska. Specifically, users will be able to view 1) intrinsic potential model calculations for 5 Pacific salmonids (Chinook, chum, pink, sockeye, and coho salmon) and northern pike and 2) all parent nodes ofFish and Climate Change (FiCli) Database: Informing climate change adaptation and management actions for freshwater fishes
Inland fishes provide important ecosystem services to communities worldwide and are especially vulnerable to the impacts of climate change. Fish respond to climate change in diverse and nuanced ways, which creates challenges for practitioners of fish conservation, climate change adaptation, and management. Although climate change is known to affect fish globally, a comprehensive online, public dat - Publications
Filter Total Items: 32
Reducing uncertainty in climate change responses of inland fishes: A decision-path approach
Climate change will continue to be an important consideration for conservation practitioners. However, uncertainty in identifying appropriate management strategies, particularly for understudied species and regions, constrains the implementation of science-based solutions and adaptation strategies. Here, we share a decision-path approach to reduce uncertainty in climate change responses of inlandAuthorsAbigail Lynch, Bonnie Myers, Jesse P. Wong, Cindy Chu, Ralph W. Tingley, Jeffrey A. Falke, Thomas J. Kwak, Craig Paukert, Trevor J. KrabbenhoftClimate change effects on North American fish and fisheries to inform adaptation strategies
Climate change is a global persistent threat to fish and fish habitats throughout North America. Climate-induced modification of environmental regimes, including changes in streamflow, water temperature, salinity, storm surges, and habitat connectivity can change fish physiology, disrupt spawning cues, cause fish extinctions and invasions, and alter fish community structure. Reducing greenhouse emAuthorsCraig Paukert, Julian D. Olden, Abigail Lynch, Dave Brashears, R. Christopher Chambers, Cindy Chu, Margaret Daly, Kimberly L. Dibble, Jeffrey A. Falke, Dan Issak, Peter C. Jacobson, Olaf P. Jensen, Daphne MunroeAssessing potential stock structure of adult Coho Salmon in a small Alaska watershed: Quantifying run timing, spawning locations, and holding areas with radiotelemetry
Run timing and spatial locations of spawning habitats are often used to identify stocks for conservation planning or management of salmonid fishes. Although complex stock structure is most common within large watersheds with diverse habitats, even small drainages can produce multiple co-occurring spatially or temporally isolated populations or “stocks.” This project sought to address the potentialAuthorsM. E. Stratton, H. Finkle, Jeffrey A. Falke, P. A. H. WestleyHigh-resolution remote sensing and multistate occupancy estimation identify drivers of spawning site selection in fall chum salmon (Oncorhynchus keta) across a sub-Arctic riverscape
Groundwater upwellings provide warmer, stable overwinter temperatures for developing salmon embryos, which may be particularly important in cold, braided, gravel-bed sub-Arctic rivers. We used a three-year time series of aerial counts and remote sensing to estimate the distribution of low and high aggregations of spawning fall chum salmon (Oncorhynchus keta), classify approximately 0.5 km long rivAuthorsChelsea M. Clawson, Jeffrey A. Falke, Larissa L. Bailey, Joshua Rose, Anupma Prakash, Aaron E. MartinVulnerability of Pacific salmon to invasion of northern pike (Esox lucius) in Southcentral Alaska
The relentless role of invasive species in the extinction of native biota requires predictions of ecosystem vulnerability to inform proactive management strategies. The worldwide invasion and range expansion of predatory northern pike (Esox lucius) has been linked to the decline of native fishes and tools are needed to predict the vulnerability of habitats to invasion over broad geographic scales.AuthorsChase S. Jalbert, Jeffrey A. Falke, Andrés López, Kristine J. Dunker, Adam J. Sepulveda, Peter A. H. WestleyDeterminants of gray wolf (Canis lupus) sightings in Denali National Park
Wildlife viewing within protected areas is an increasingly popular recreational activity. Management agencies are often tasked with providing these opportunities, yet quantitative analyses of factors influencing wildlife sightings are lacking. We analyzed locations of GPS-collared wolves and wolf sightings from 2945 trips in Denali National Park and Preserve, Alaska, USA, to provide a mechanisticAuthorsBridget L. Borg, Stephen M. Arthur, Jeffrey A. Falke, Laura R. PrughFiCli, the Fish and Climate Change Database, informs climate adaptation and management for freshwater fishes
Inland fishes provide important ecosystem services to communities worldwide and are especially vulnerable to the impacts of climate change. Fish respond to climate change in diverse and nuanced ways, which creates challenges for practitioners of fish conservation, climate change adaptation, and management. Although climate change is known to affect fish globally, a comprehensive online, public datAuthorsTrevor J. Krabbenhoft, Bonnie Jean Evaline Myers, Jesse Wong, Cindy Chu, Ralph W. III Tingley, Jeffrey A. Falke, Thomas J. Kwak, Craig P. Paukert, Abigail LynchThermal diversity of salmon streams in the Matanuska-Susitna Basin, Alaska
We present the first description of summer stream thermal regimes in Alaska using metrics that represent the magnitude, variability, frequency, duration, and timing of temperature events related to salmon life histories. We used cluster analysis to characterize thermal regimes present in the Matanuska-Susitna (Mat-Su) Basin based on 10 nonredundant temperature metrics and identified the most imporAuthorsRebecca Shaftel, Sue Mauger, Jeffrey A. Falke, Daniel Rinella, Jeff Davis, Leslie JonesA classification of streamflow patterns across the coastal Gulf of Alaska
Streamflow controls many freshwater and marine processes, including salinity profiles, sediment composition, fluxes of nutrients, and the timing of animal migrations. Watersheds that border the Gulf of Alaska (GOA) comprise over 400,000 km2 of largely pristine freshwater habitats and provide ecosystem services such as reliable fisheries for local and global food production. Yet no comprehensive waAuthorsChristopher J. Sergeant, Jeffrey A. Falke, Rebecca A. Bellmore, J. Ryan Bellmore, Ryan L. CrumleyEnergetic status of Alaskan Chinook Salmon: Interpopulation comparisons and predictive modeling using bioelectrical impedance analysis
Adult Pacific Salmon Oncorhynchus spp. undertake energetically demanding migrations wherein they must have adequate energy reserves to survive to spawning locations and reproduce. Proximate analysis provides insight into available energy stores (e.g., lipids), but the ability to non-lethally monitor energetic status may be useful for managers to better understand how energetic status affects salmoAuthorsKristin R. Courtney, Jeffrey A. Falke, M. Keith Cox, Jeff NicholsClimatic variation drives growth potential of juvenile Chinook Salmon (Oncorhynchus tshawytscha) along a sub-Arctic boreal riverscape
Climatic variation is a key driver of freshwater physical processes that in turn control stream fish growth and population dynamics at fine spatial scales and species distributions across broad landscapes. A recent downturn in Chinook Salmon returns across the Yukon River basin, Alaska, USA, and Yukon Territories, Canada, has led to hardship among user groups and increased interest in understandinAuthorsJeffrey A. Falke, Brock M. Huntsman, Erik R. SchoenEnergetic status and bioelectrical impedance modeling of Arctic grayling Thymallus arcticus in interior Alaska Rivers
The energetic status of fishes represents energy stored as protein and lipids and reflects the ability of an individual to reproduce, migrate, and transition through life stages, ultimately influencing survival. However, traditional measurement methods, while highly accurate, are time consuming, expensive, and lethal, and nonlethal methods such as condition factor may not adequately characterize eAuthorsJeffrey A. Falke, Lauren T. Bailey, Kevin M. Fraley, Michael J. Lunde, Andrew D. Gryska - Software
Code to Support Hypoxia vulnerability in the salmon watersheds of Southeast Alaska
Oxygen depletion events (hypoxia) in coastal aquatic ecosystems occur more frequently, yet their causes and consequences remain poorly understood. We identified key drivers of hypoxia in Southeast Alaska watersheds for long-term hypoxia monitoring. This software release contains one R script that can be used to calculate hypoxia risk from environmental variables. This R code will re-create Figure