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Annika Walters, PhD

Assistant Unit Leader - Wyoming Cooperative Fish and Wildlife Research Unit

Annika's research has focused on aquatic ecosystems and how these ecosystems are altered by natural and anthropogenic disturbance.

Research Interests

Annika is interested in the resistance and resilience of aquatic communities to disturbance. Her research addresses disturbances that are relevant to the conservation and management of aquatic ecosystems through a combination of field observation, experimentation, and modeling. Disturbances of interest include flow alteration, climate change, nutrient loading, invasive species, and energy development. Most of her research involves fish that are of conservation concern and is set in a management context.

Teaching Interests

Annika currently teaches advanced fisheries management and seminars on topics of interest at University of Wyoming.

Professional Experience

  • Assistant Unit Leader, Wyoming Cooperative Fish and Wildlife Research Unit, 2011-

Education and Certifications

  • PhD, Oklahoma State University, 2001

  • MS, University of New Hampshire, 1997

  • BS, SUNY - College of Environmental Science and Forestry, 1992

Science and Products

link
Stream in the Flathead National Forest during fall

The Implications of Stream Fragmentation for Climate Change Resilience of Northern Prairie Fishes

Dry stream sections are characteristic of most prairie streams. Native fish are highly adapted to variable environments, using refuge habitats (e.g., remaining wet stream fragments) to recolonize areas after seasonal drying. However, dams and other barriers can prevent recolonization of seasonally-dry stream sections habitats known to be critical spawning and rearing areas for many species. This p
By
Climate Adaptation Science Centers
link

The Implications of Stream Fragmentation for Climate Change Resilience of Northern Prairie Fishes

Dry stream sections are characteristic of most prairie streams. Native fish are highly adapted to variable environments, using refuge habitats (e.g., remaining wet stream fragments) to recolonize areas after seasonal drying. However, dams and other barriers can prevent recolonization of seasonally-dry stream sections habitats known to be critical spawning and rearing areas for many species. This p
Learn More
link
Brown water meets clear water

Development of a Surface Water Index of Permanence (SWIPe) Database to Assess Surface Water Availability for Ecohydrological Refugia

Surface-water availability has been identified as one of the biggest issues facing society in the 21st century. Where and when water is on the landscape can have profound impacts on the economy, wildlife behavior, recreational use, industrial practices, energy development, and many other aspects of life, society, and the environment. Projections indicate that surface-water availability will be gen
By
Climate Adaptation Science Centers
link

Development of a Surface Water Index of Permanence (SWIPe) Database to Assess Surface Water Availability for Ecohydrological Refugia

Surface-water availability has been identified as one of the biggest issues facing society in the 21st century. Where and when water is on the landscape can have profound impacts on the economy, wildlife behavior, recreational use, industrial practices, energy development, and many other aspects of life, society, and the environment. Projections indicate that surface-water availability will be gen
Learn More
link
USGS science for a changing world logo

Synthesizing Multiple Long-Term Datasets to Test Flow Ecology Relationships for Fishes - Workshop

River ecosystems support a wide diversity of biota, including thousands of fish species, which are variously adapted to the dynamic environments provided by flowing-water habitats. One of the primary ways that human activities diminish the biological capacity of rivers is by altering the natural hydrologic variability of river systems through regulation and diversion of streamflow for other uses.
By
John Wesley Powell Center for Analysis and Synthesis
link

Synthesizing Multiple Long-Term Datasets to Test Flow Ecology Relationships for Fishes - Workshop

River ecosystems support a wide diversity of biota, including thousands of fish species, which are variously adapted to the dynamic environments provided by flowing-water habitats. One of the primary ways that human activities diminish the biological capacity of rivers is by altering the natural hydrologic variability of river systems through regulation and diversion of streamflow for other uses.
Learn More

Roundtail Chub and Flannelmouth Sucker movement data within the Blacks Fork subbasin, Wyoming 2019-2021

The dataset includes Roundtail Chub and Flannelmouth Sucker detections at passive integrated transponder (PIT) tag antenna systems. We installed nine instream Biomark PIT-tag antenna systems (five 24-meter and four 9-meter antennas) in a pass-over orientation throughout the Blacks Fork subbasin. In addition to the fixed antennas, we used a Biomark inflatable antenna and two Biomark submersible PIT
By
Cooperative Research Units

Brook Stickleback occurrence and environmental data 2020-2021

Brook Stickleback Culaea inconstans is an aquatic invasive species in Wyoming that may pose a risk to native biodiversity. Our aim was to evaluate the current risk Brook Stickleback poses to native fish species in the North Platte River drainage. We updated the current distribution of Brook Stickleback, evaluated for possible range expansion, and determined landscape-level habitat drivers and occu
By
Cooperative Research Units

Wyoming crayfish assemblages 1969 - 2020

Crayfish have experienced extensive community reorganization as a result of global change, with some species becoming globally invasive while others have become rare or extinct. We combined historical and contemporary sampling data to determine temporal trends of crayfish assemblages of Wyoming, United States (1969–2020). The dataset includes previous statewide surveys and more narrow studies focu
By
Cooperative Research Units

Isotopic Data for Fishes in Wyoming, USA

Trophic studies can provide valuable information on the risk an invader poses to native species. Brook Stickleback Culaea inconstans is an invasive fish species in Wyoming whose effect on native fish assemblages is poorly understood. Our goal was to understand the potential for competitive interactions between Brook Stickleback and native fishes. We used stable isotopes of carbon (ẟ13C) and nitrog
By
Cooperative Research Units

Fish movement and colonization in the Wyoming Range 2018-2019

Fish colonization ability may be one factor affecting population resilience after disturbance. We conducted displacement experiments in headwater streams in Wyoming, U.S.A. to evaluate mottled sculpin (Cottus bairdii) and mountain sucker (Catostomus platyrhynchus) colonization ability. Specifically, we (1) determined if fish could colonize sites rapidly after displacement, (2) evaluated site-level
By
Cooperative Research Units

Habitat and fish field survey data from Wyoming Range streams in 2012 and 2013

Stream habitat characteristics, energy development metrics, and fish catch per unit effort data for 91 sites (100m stream reach) sampled in the summers of 2012 and 2013.We sampled four streams in the Dry Piney Drainage (Dry Piney, Beaver Dam, Black Canyon, and North Black Canyon), five in the Fogarty Drainage (North and South Fogarty, North and South Pine Grove, and Sawmill) and four in the South
By
Cooperative Research Units
Filter Total Items: 40

Redd superimposition mediates the accuracy, precision, and significance of redd counts for cutthroat trout

Redd counts are commonly applied to estimate spawning population size for salmonids and allow for broad spatial and temporal coverage in monitoring efforts. However, the utility of redd counts may be compromised by observation error, particularly with respect to superimposition, where later arriving spawners construct redds overlapping existing redds. Here, we provide a mechanistic evaluation of t
Authors
Jeffrey R. Baldock, Robert Al-Chokhachy, Timothy E. Walsworth, Annika W. Walters
By
Ecosystems Mission Area, Northern Rocky Mountain Science Center

Simple statistical models can be sufficient for testing hypotheses with population time series data

Time-series data offer wide-ranging opportunities to test hypotheses about the physical and biological factors that influence species abundances. Although sophisticated models have been developed and applied to analyze abundance time series, they require information about species detectability that is often unavailable. We propose that in many cases, simpler models are adequate for testing hypothe
Authors
Seth J. Wenger, Edward S. Stowe, Keith B. Gido, Mary Freeman, Yoichiro Kanno, Nathan R. Franssen, Julian Olden, N. LeRoy Poff, Annika W. Walters, Phillip M. Bumpers, Meryl C. Mims, Mevin B. Hooten, Xinyi Lu
By
Cooperative Research Units, Eastern Ecological Science Center

Toward improved prediction of streamflow effects on freshwater fishes

Understanding the effects of hydrology on fish populations is essential to managing for native fish conservation. However, despite decades of research illustrating streamflow influences on fish habitat, reproduction and survival, biologists remain challenged when tasked with predicting how fish populations will respond to changes in flow regimes. This uncertainty stems from insufficient understand
Authors
Mary Freeman, Kevin R. Bestgen, Daren Carlisle, Emmanuel A. Frimpong, Nathan R. Franssen, Ketih B. Gido, Elise R. Irwin, Yoichiro Kanno, Charles H. Luce, S. Kyle McKay, Meryl C. Mims, Julian D. Olden, N. LeRoy Poff, David L. Propst, Laura Rack, Allison H. Roy, Edward S. Stowe, Annika W. Walters, Seth J. Wenger
By
Cooperative Research Units, Eastern Ecological Science Center

Movement dynamics and survival of stocked Colorado River Cutthroat Trout

The ability of native fish to establish self-sustaining populations when reintroduced to vacant habitats is variable. We evaluated factors that potentially affect the reintroduction success of juvenile Colorado River Cutthroat Trout Oncorhynchus clarkii pleuriticus that were reintroduced to an isolated watershed and were experiencing suboptimal survival and recruitment. We conducted a 3-year mark–
Authors
Alex G. LeCheminant, Gabriel M. Barrile, Shannon E. Albeke, Annika W. Walters
By
Cooperative Research Units

Livestock grazing, climatic variation, and breeding phenology jointly shape disease dynamics and survival in a wild amphibian

Wildlife responses to infectious disease can be influenced by environmental stressors that alter host-pathogen dynamics. We investigated how livestock grazing, climatic variation, and breeding phenology influence disease prevalence and annual survival in boreal toad (Anaxyrus boreas boreas) populations challenged with Batrachochytrium dendrobatidis (Bd), a fungal pathogen implicated in global amph
Authors
Gabriel M. Barrile, Annika W. Walters, Anna D. Chalfoun
By
Cooperative Research Units

Rapid colonisation post-displacement contributes to native fish resilience

Native freshwater fish are experiencing global declines. Determining what drives native fish resilience to disturbance is crucial to understanding their persistence in the face of multiple stressors. Fish colonisation ability may be one factor affecting population resilience after disturbance. We conducted displacement experiments in headwater streams in Wyoming, USA, to evaluate mottled sculpin (
Authors
Samantha L. Alford, Annika W. Walters
By
Cooperative Research Units

U.S. Geological Survey science for the Wyoming Landscape Conservation Initiative—2018 annual report

The Wyoming Landscape Conservation Initiative (WLCI) was established in 2007 as a collaborative interagency partnership to develop and implement science-based conservation actions. During the past 11 years, partners from U.S. Geological Survey (USGS), State and Federal land management agencies, universities, and the public have collaborated to implement a long-term (more than 10 years) science-bas
Authors
Patrick J. Anderson, Cameron L. Aldridge, Jason S. Alexander, Timothy J. Assal, Steven Aulenbach, Zachary H. Bowen, Anna D. Chalfoun, Geneva W. Chong, Holly Copeland, David R. Edmunds, Steve Germaine, Tabitha Graves, Julie A. Heinrichs, Collin G. Homer, Christopher Huber, Aaron N. Johnston, Matthew J. Kauffman, Daniel J. Manier, Ryan R. McShane, Cheryl A. Eddy-Miller, Kirk A. Miller, Adrian P. Monroe, Michael S. O'Donnell, Anna Ortega, Annika W. Walters, Daniel J. Wieferich, Teal B. Wyckoff, Linda Zeigenfuss
By
Ecosystems Mission Area, Water Resources Mission Area, Earth Resources Observation and Science (EROS) Center , Fort Collins Science Center, Nebraska Water Science Center, Northern Rocky Mountain Science Center, Core Research Center

Informed breeding dispersal following stochastic changes to patch quality in a pond-breeding amphibian

The unidirectional movement of animals between breeding patches (i.e. breeding dispersal) has profound implications for the ecological and evolutionary dynamics of spatially structured populations. In spatiotemporally variable environments, individuals are expected to adjust their dispersal decisions according to information gathered on the environmental and/or social cues that reflect the fitness
Authors
Gabriel M. Barrile, Annika W. Walters, Matthew Webster, Anna D. Chalfoun
By
Cooperative Research Units

Historical data provide important context for understanding declines in Cutthroat Trout

We used historical stocking and population survey records of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri and other salmonids in the North Fork Shoshone River drainage, Wyoming to summarize fish stocking history and population trends. Based on 98 years of historical records, we found that despite extensive stocking of Yellowstone Cutthroat Trout and minimal stocking of nonnative salmo
Authors
Brittany J. Nordberg, Elizabeth G. Mandeville, Annika W. Walters, Jason C. Burckhardt, Catherine E. Wagner
By
Cooperative Research Units

Biotic and abiotic determinants of finescale dace distribution at the southern edge of their range

AimThe factors that set range limits for animal populations can inform management plans aimed at maintaining regional biodiversity. We examine abiotic and biotic drivers of the distribution of finescale dace (Chrosomus neogaeus) in two Great Plains basins to identify limiting factors for a threatened freshwater fish population at the edge of their range.LocationGreat Plains, Nebraska, South Dakota
Authors
Evan C. J. Booher, Annika W. Walters
By
Cooperative Research Units

Warmer temperatures interact with salinity to weaken physiological facilitation to stress in freshwater fishes

Management of stressors requires an understanding of how multiple stressors interact, how different species respond to those interactions and the underlying mechanisms driving observed patterns in species' responses. Salinization and rising temperatures are two pertinent stressors predicted to intensify in freshwater ecosystems, posing concern for how susceptible organisms achieve and maintain hom
Authors
Richard H. Walker, Geoffrey D. Smith, Spencer B . Hudson, Susannah S. Susannah S. French, Annika W. Walters
By
Cooperative Research Units

Infection status as the basis for habitat choices in a wild amphibian

Animals challenged with disease may select specific habitat conditions that help prevent or reduce infection. Whereas preinfection avoidance of habitats with a high risk of disease exposure has been documented in both captive and free-ranging animals, evidence of switching habitats after infection to support the clearing of the infection is limited to laboratory experiments. The extent to which wi
Authors
Gabriel M. Barrile, Anna D. Chalfoun, Annika W. Walters
By
Cooperative Research Units

Science and Products

link
Stream in the Flathead National Forest during fall

The Implications of Stream Fragmentation for Climate Change Resilience of Northern Prairie Fishes

Dry stream sections are characteristic of most prairie streams. Native fish are highly adapted to variable environments, using refuge habitats (e.g., remaining wet stream fragments) to recolonize areas after seasonal drying. However, dams and other barriers can prevent recolonization of seasonally-dry stream sections habitats known to be critical spawning and rearing areas for many species. This p
By
Climate Adaptation Science Centers
link

The Implications of Stream Fragmentation for Climate Change Resilience of Northern Prairie Fishes

Dry stream sections are characteristic of most prairie streams. Native fish are highly adapted to variable environments, using refuge habitats (e.g., remaining wet stream fragments) to recolonize areas after seasonal drying. However, dams and other barriers can prevent recolonization of seasonally-dry stream sections habitats known to be critical spawning and rearing areas for many species. This p
Learn More
link
Brown water meets clear water

Development of a Surface Water Index of Permanence (SWIPe) Database to Assess Surface Water Availability for Ecohydrological Refugia

Surface-water availability has been identified as one of the biggest issues facing society in the 21st century. Where and when water is on the landscape can have profound impacts on the economy, wildlife behavior, recreational use, industrial practices, energy development, and many other aspects of life, society, and the environment. Projections indicate that surface-water availability will be gen
By
Climate Adaptation Science Centers
link

Development of a Surface Water Index of Permanence (SWIPe) Database to Assess Surface Water Availability for Ecohydrological Refugia

Surface-water availability has been identified as one of the biggest issues facing society in the 21st century. Where and when water is on the landscape can have profound impacts on the economy, wildlife behavior, recreational use, industrial practices, energy development, and many other aspects of life, society, and the environment. Projections indicate that surface-water availability will be gen
Learn More
link
USGS science for a changing world logo

Synthesizing Multiple Long-Term Datasets to Test Flow Ecology Relationships for Fishes - Workshop

River ecosystems support a wide diversity of biota, including thousands of fish species, which are variously adapted to the dynamic environments provided by flowing-water habitats. One of the primary ways that human activities diminish the biological capacity of rivers is by altering the natural hydrologic variability of river systems through regulation and diversion of streamflow for other uses.
By
John Wesley Powell Center for Analysis and Synthesis
link

Synthesizing Multiple Long-Term Datasets to Test Flow Ecology Relationships for Fishes - Workshop

River ecosystems support a wide diversity of biota, including thousands of fish species, which are variously adapted to the dynamic environments provided by flowing-water habitats. One of the primary ways that human activities diminish the biological capacity of rivers is by altering the natural hydrologic variability of river systems through regulation and diversion of streamflow for other uses.
Learn More

Roundtail Chub and Flannelmouth Sucker movement data within the Blacks Fork subbasin, Wyoming 2019-2021

The dataset includes Roundtail Chub and Flannelmouth Sucker detections at passive integrated transponder (PIT) tag antenna systems. We installed nine instream Biomark PIT-tag antenna systems (five 24-meter and four 9-meter antennas) in a pass-over orientation throughout the Blacks Fork subbasin. In addition to the fixed antennas, we used a Biomark inflatable antenna and two Biomark submersible PIT
By
Cooperative Research Units

Brook Stickleback occurrence and environmental data 2020-2021

Brook Stickleback Culaea inconstans is an aquatic invasive species in Wyoming that may pose a risk to native biodiversity. Our aim was to evaluate the current risk Brook Stickleback poses to native fish species in the North Platte River drainage. We updated the current distribution of Brook Stickleback, evaluated for possible range expansion, and determined landscape-level habitat drivers and occu
By
Cooperative Research Units

Wyoming crayfish assemblages 1969 - 2020

Crayfish have experienced extensive community reorganization as a result of global change, with some species becoming globally invasive while others have become rare or extinct. We combined historical and contemporary sampling data to determine temporal trends of crayfish assemblages of Wyoming, United States (1969–2020). The dataset includes previous statewide surveys and more narrow studies focu
By
Cooperative Research Units

Isotopic Data for Fishes in Wyoming, USA

Trophic studies can provide valuable information on the risk an invader poses to native species. Brook Stickleback Culaea inconstans is an invasive fish species in Wyoming whose effect on native fish assemblages is poorly understood. Our goal was to understand the potential for competitive interactions between Brook Stickleback and native fishes. We used stable isotopes of carbon (ẟ13C) and nitrog
By
Cooperative Research Units

Fish movement and colonization in the Wyoming Range 2018-2019

Fish colonization ability may be one factor affecting population resilience after disturbance. We conducted displacement experiments in headwater streams in Wyoming, U.S.A. to evaluate mottled sculpin (Cottus bairdii) and mountain sucker (Catostomus platyrhynchus) colonization ability. Specifically, we (1) determined if fish could colonize sites rapidly after displacement, (2) evaluated site-level
By
Cooperative Research Units

Habitat and fish field survey data from Wyoming Range streams in 2012 and 2013

Stream habitat characteristics, energy development metrics, and fish catch per unit effort data for 91 sites (100m stream reach) sampled in the summers of 2012 and 2013.We sampled four streams in the Dry Piney Drainage (Dry Piney, Beaver Dam, Black Canyon, and North Black Canyon), five in the Fogarty Drainage (North and South Fogarty, North and South Pine Grove, and Sawmill) and four in the South
By
Cooperative Research Units
Filter Total Items: 40

Redd superimposition mediates the accuracy, precision, and significance of redd counts for cutthroat trout

Redd counts are commonly applied to estimate spawning population size for salmonids and allow for broad spatial and temporal coverage in monitoring efforts. However, the utility of redd counts may be compromised by observation error, particularly with respect to superimposition, where later arriving spawners construct redds overlapping existing redds. Here, we provide a mechanistic evaluation of t
Authors
Jeffrey R. Baldock, Robert Al-Chokhachy, Timothy E. Walsworth, Annika W. Walters
By
Ecosystems Mission Area, Northern Rocky Mountain Science Center

Simple statistical models can be sufficient for testing hypotheses with population time series data

Time-series data offer wide-ranging opportunities to test hypotheses about the physical and biological factors that influence species abundances. Although sophisticated models have been developed and applied to analyze abundance time series, they require information about species detectability that is often unavailable. We propose that in many cases, simpler models are adequate for testing hypothe
Authors
Seth J. Wenger, Edward S. Stowe, Keith B. Gido, Mary Freeman, Yoichiro Kanno, Nathan R. Franssen, Julian Olden, N. LeRoy Poff, Annika W. Walters, Phillip M. Bumpers, Meryl C. Mims, Mevin B. Hooten, Xinyi Lu
By
Cooperative Research Units, Eastern Ecological Science Center

Toward improved prediction of streamflow effects on freshwater fishes

Understanding the effects of hydrology on fish populations is essential to managing for native fish conservation. However, despite decades of research illustrating streamflow influences on fish habitat, reproduction and survival, biologists remain challenged when tasked with predicting how fish populations will respond to changes in flow regimes. This uncertainty stems from insufficient understand
Authors
Mary Freeman, Kevin R. Bestgen, Daren Carlisle, Emmanuel A. Frimpong, Nathan R. Franssen, Ketih B. Gido, Elise R. Irwin, Yoichiro Kanno, Charles H. Luce, S. Kyle McKay, Meryl C. Mims, Julian D. Olden, N. LeRoy Poff, David L. Propst, Laura Rack, Allison H. Roy, Edward S. Stowe, Annika W. Walters, Seth J. Wenger
By
Cooperative Research Units, Eastern Ecological Science Center

Movement dynamics and survival of stocked Colorado River Cutthroat Trout

The ability of native fish to establish self-sustaining populations when reintroduced to vacant habitats is variable. We evaluated factors that potentially affect the reintroduction success of juvenile Colorado River Cutthroat Trout Oncorhynchus clarkii pleuriticus that were reintroduced to an isolated watershed and were experiencing suboptimal survival and recruitment. We conducted a 3-year mark–
Authors
Alex G. LeCheminant, Gabriel M. Barrile, Shannon E. Albeke, Annika W. Walters
By
Cooperative Research Units

Livestock grazing, climatic variation, and breeding phenology jointly shape disease dynamics and survival in a wild amphibian

Wildlife responses to infectious disease can be influenced by environmental stressors that alter host-pathogen dynamics. We investigated how livestock grazing, climatic variation, and breeding phenology influence disease prevalence and annual survival in boreal toad (Anaxyrus boreas boreas) populations challenged with Batrachochytrium dendrobatidis (Bd), a fungal pathogen implicated in global amph
Authors
Gabriel M. Barrile, Annika W. Walters, Anna D. Chalfoun
By
Cooperative Research Units

Rapid colonisation post-displacement contributes to native fish resilience

Native freshwater fish are experiencing global declines. Determining what drives native fish resilience to disturbance is crucial to understanding their persistence in the face of multiple stressors. Fish colonisation ability may be one factor affecting population resilience after disturbance. We conducted displacement experiments in headwater streams in Wyoming, USA, to evaluate mottled sculpin (
Authors
Samantha L. Alford, Annika W. Walters
By
Cooperative Research Units

U.S. Geological Survey science for the Wyoming Landscape Conservation Initiative—2018 annual report

The Wyoming Landscape Conservation Initiative (WLCI) was established in 2007 as a collaborative interagency partnership to develop and implement science-based conservation actions. During the past 11 years, partners from U.S. Geological Survey (USGS), State and Federal land management agencies, universities, and the public have collaborated to implement a long-term (more than 10 years) science-bas
Authors
Patrick J. Anderson, Cameron L. Aldridge, Jason S. Alexander, Timothy J. Assal, Steven Aulenbach, Zachary H. Bowen, Anna D. Chalfoun, Geneva W. Chong, Holly Copeland, David R. Edmunds, Steve Germaine, Tabitha Graves, Julie A. Heinrichs, Collin G. Homer, Christopher Huber, Aaron N. Johnston, Matthew J. Kauffman, Daniel J. Manier, Ryan R. McShane, Cheryl A. Eddy-Miller, Kirk A. Miller, Adrian P. Monroe, Michael S. O'Donnell, Anna Ortega, Annika W. Walters, Daniel J. Wieferich, Teal B. Wyckoff, Linda Zeigenfuss
By
Ecosystems Mission Area, Water Resources Mission Area, Earth Resources Observation and Science (EROS) Center , Fort Collins Science Center, Nebraska Water Science Center, Northern Rocky Mountain Science Center, Core Research Center

Informed breeding dispersal following stochastic changes to patch quality in a pond-breeding amphibian

The unidirectional movement of animals between breeding patches (i.e. breeding dispersal) has profound implications for the ecological and evolutionary dynamics of spatially structured populations. In spatiotemporally variable environments, individuals are expected to adjust their dispersal decisions according to information gathered on the environmental and/or social cues that reflect the fitness
Authors
Gabriel M. Barrile, Annika W. Walters, Matthew Webster, Anna D. Chalfoun
By
Cooperative Research Units

Historical data provide important context for understanding declines in Cutthroat Trout

We used historical stocking and population survey records of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri and other salmonids in the North Fork Shoshone River drainage, Wyoming to summarize fish stocking history and population trends. Based on 98 years of historical records, we found that despite extensive stocking of Yellowstone Cutthroat Trout and minimal stocking of nonnative salmo
Authors
Brittany J. Nordberg, Elizabeth G. Mandeville, Annika W. Walters, Jason C. Burckhardt, Catherine E. Wagner
By
Cooperative Research Units

Biotic and abiotic determinants of finescale dace distribution at the southern edge of their range

AimThe factors that set range limits for animal populations can inform management plans aimed at maintaining regional biodiversity. We examine abiotic and biotic drivers of the distribution of finescale dace (Chrosomus neogaeus) in two Great Plains basins to identify limiting factors for a threatened freshwater fish population at the edge of their range.LocationGreat Plains, Nebraska, South Dakota
Authors
Evan C. J. Booher, Annika W. Walters
By
Cooperative Research Units

Warmer temperatures interact with salinity to weaken physiological facilitation to stress in freshwater fishes

Management of stressors requires an understanding of how multiple stressors interact, how different species respond to those interactions and the underlying mechanisms driving observed patterns in species' responses. Salinization and rising temperatures are two pertinent stressors predicted to intensify in freshwater ecosystems, posing concern for how susceptible organisms achieve and maintain hom
Authors
Richard H. Walker, Geoffrey D. Smith, Spencer B . Hudson, Susannah S. Susannah S. French, Annika W. Walters
By
Cooperative Research Units

Infection status as the basis for habitat choices in a wild amphibian

Animals challenged with disease may select specific habitat conditions that help prevent or reduce infection. Whereas preinfection avoidance of habitats with a high risk of disease exposure has been documented in both captive and free-ranging animals, evidence of switching habitats after infection to support the clearing of the infection is limited to laboratory experiments. The extent to which wi
Authors
Gabriel M. Barrile, Anna D. Chalfoun, Annika W. Walters
By
Cooperative Research Units