Annika Walters, PhD (Former Employee)
Science and Products
Filter Total Items: 71
Simple statistical models can be sufficient for testing hypotheses with population time series data 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...
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
Wildfire influences individual growth and breeding dispersal, but not survival and recruitment in a montane amphibian Wildfire influences individual growth and breeding dispersal, but not survival and recruitment in a montane amphibian
Global wildfire regimes are changing rapidly, with widespread increases in the size, frequency, duration, and severity of wildfires. Whereas the effects of wildfire on ecological state variables such as occupancy, abundance, and species diversity are relatively well documented, changes in population vital rates (e.g., survival, recruitment) and individual responses (e.g., growth...
Authors
Gabriel M. Barrile, Anna D. Chalfoun, Wendy A. Estes-Zumpf, Annika W. Walters
Hybridization decreases native cutthroat trout reproductive fitness Hybridization decreases native cutthroat trout reproductive fitness
Examining natural selection in wild populations is challenging, but crucial to understanding many ecological and evolutionary processes. Additionally, in hybridizing populations, natural selection may be an important determinant of the eventual outcome of hybridization. We characterized several components of relative fitness in hybridizing populations of Yellowstone cutthroat trout and...
Authors
William C. Rosenthal, John M. Fennell, Elizabeth G. Mandeville, Jason C. Burckhardt, Annika W. Walters, Catherine E. Wagner
Temporal segregation in spawning between native Yellowstone cutthroat trout and introduced rainbow trout Temporal segregation in spawning between native Yellowstone cutthroat trout and introduced rainbow trout
Hybridisation with introduced taxa poses a threat to native fish populations. Mechanisms of reproductive isolation can limit or prevent hybridisation between closely related species. Understanding how these mechanisms interact between the same species across geographically distinct occurrences of secondary contact, and how regional factors influence them, can inform our understanding of
Authors
John M. Fennell, William C. Rosenthal, Catherine E. Wagner, Jason C. Burckhardt, Annika W. Walters
Stage-specific environmental correlates of reproductive success in Boreal Toads (Anaxyrus boreas boreas) Stage-specific environmental correlates of reproductive success in Boreal Toads (Anaxyrus boreas boreas)
Compensatory recruitment can facilitate the persistence of populations experiencing high adult mortality. Because early life-stages of many taxa, including amphibians, are difficult to mark and recapture, sources of variation in survival at these stages often are unknown, which creates barriers to improving in situ recruitment rates. We leveraged count data and open N-mixture models to...
Authors
Gabriel M. Barrile, Annika W. Walters, Anna D. Chalfoun
Toward improved prediction of streamflow effects on freshwater fishes 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
Authors
Mary Freeman, Kevin R. Bestgen, Daren M. 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
Climatic drivers and ecological impacts of a rapid range expansion by non-native smallmouth bass Climatic drivers and ecological impacts of a rapid range expansion by non-native smallmouth bass
Smallmouth bass (Micropterus dolomieu) are a globally introduced fish species that have experienced widespread range expansions in recent decades and which can have deleterious effects on native fish communities. Rapidly assessing their expansions will aid conservation and management actions geared towards controlling their spread and mitigating their impacts. Smallmouth bass have...
Authors
Mark A. Kirk, Bryan M. Maitland, Brian T. Hickerson, Annika W. Walters, Frank J. Rahel
Identifying translocation sites for a climate relict population of Finescale Dace Identifying translocation sites for a climate relict population of Finescale Dace
Translocation is a management strategy that seeks to address threats to fish and wildlife populations by establishing new populations in ecologically suitable areas. Populations of Finescale Dace Chrosomus neogaeus in the Great Plains may benefit from translocation, as they exhibit a climate relict natural history that has led to a disjunct distribution and minimal dispersal...
Authors
Evan C.J. Booher, Annika W. Walters
Movement dynamics and survival of stocked Colorado River Cutthroat Trout 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...
Authors
Alex G. LeCheminant, Gabriel M. Barrile, Shannon E. Albeke, Annika W. Walters
Livestock grazing, climatic variation, and breeding phenology jointly shape disease dynamics and survival in a wild amphibian 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...
Authors
Gabriel M. Barrile, Annika W. Walters, Anna D. Chalfoun
Rapid colonisation post-displacement contributes to native fish resilience 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...
Authors
Samantha L. Alford, Annika W. Walters
U.S. Geological Survey science for the Wyoming Landscape Conservation Initiative—2018 annual report 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)...
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 A. 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
Science and Products
Filter Total Items: 71
Simple statistical models can be sufficient for testing hypotheses with population time series data 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...
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
Wildfire influences individual growth and breeding dispersal, but not survival and recruitment in a montane amphibian Wildfire influences individual growth and breeding dispersal, but not survival and recruitment in a montane amphibian
Global wildfire regimes are changing rapidly, with widespread increases in the size, frequency, duration, and severity of wildfires. Whereas the effects of wildfire on ecological state variables such as occupancy, abundance, and species diversity are relatively well documented, changes in population vital rates (e.g., survival, recruitment) and individual responses (e.g., growth...
Authors
Gabriel M. Barrile, Anna D. Chalfoun, Wendy A. Estes-Zumpf, Annika W. Walters
Hybridization decreases native cutthroat trout reproductive fitness Hybridization decreases native cutthroat trout reproductive fitness
Examining natural selection in wild populations is challenging, but crucial to understanding many ecological and evolutionary processes. Additionally, in hybridizing populations, natural selection may be an important determinant of the eventual outcome of hybridization. We characterized several components of relative fitness in hybridizing populations of Yellowstone cutthroat trout and...
Authors
William C. Rosenthal, John M. Fennell, Elizabeth G. Mandeville, Jason C. Burckhardt, Annika W. Walters, Catherine E. Wagner
Temporal segregation in spawning between native Yellowstone cutthroat trout and introduced rainbow trout Temporal segregation in spawning between native Yellowstone cutthroat trout and introduced rainbow trout
Hybridisation with introduced taxa poses a threat to native fish populations. Mechanisms of reproductive isolation can limit or prevent hybridisation between closely related species. Understanding how these mechanisms interact between the same species across geographically distinct occurrences of secondary contact, and how regional factors influence them, can inform our understanding of
Authors
John M. Fennell, William C. Rosenthal, Catherine E. Wagner, Jason C. Burckhardt, Annika W. Walters
Stage-specific environmental correlates of reproductive success in Boreal Toads (Anaxyrus boreas boreas) Stage-specific environmental correlates of reproductive success in Boreal Toads (Anaxyrus boreas boreas)
Compensatory recruitment can facilitate the persistence of populations experiencing high adult mortality. Because early life-stages of many taxa, including amphibians, are difficult to mark and recapture, sources of variation in survival at these stages often are unknown, which creates barriers to improving in situ recruitment rates. We leveraged count data and open N-mixture models to...
Authors
Gabriel M. Barrile, Annika W. Walters, Anna D. Chalfoun
Toward improved prediction of streamflow effects on freshwater fishes 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
Authors
Mary Freeman, Kevin R. Bestgen, Daren M. 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
Climatic drivers and ecological impacts of a rapid range expansion by non-native smallmouth bass Climatic drivers and ecological impacts of a rapid range expansion by non-native smallmouth bass
Smallmouth bass (Micropterus dolomieu) are a globally introduced fish species that have experienced widespread range expansions in recent decades and which can have deleterious effects on native fish communities. Rapidly assessing their expansions will aid conservation and management actions geared towards controlling their spread and mitigating their impacts. Smallmouth bass have...
Authors
Mark A. Kirk, Bryan M. Maitland, Brian T. Hickerson, Annika W. Walters, Frank J. Rahel
Identifying translocation sites for a climate relict population of Finescale Dace Identifying translocation sites for a climate relict population of Finescale Dace
Translocation is a management strategy that seeks to address threats to fish and wildlife populations by establishing new populations in ecologically suitable areas. Populations of Finescale Dace Chrosomus neogaeus in the Great Plains may benefit from translocation, as they exhibit a climate relict natural history that has led to a disjunct distribution and minimal dispersal...
Authors
Evan C.J. Booher, Annika W. Walters
Movement dynamics and survival of stocked Colorado River Cutthroat Trout 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...
Authors
Alex G. LeCheminant, Gabriel M. Barrile, Shannon E. Albeke, Annika W. Walters
Livestock grazing, climatic variation, and breeding phenology jointly shape disease dynamics and survival in a wild amphibian 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...
Authors
Gabriel M. Barrile, Annika W. Walters, Anna D. Chalfoun
Rapid colonisation post-displacement contributes to native fish resilience 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...
Authors
Samantha L. Alford, Annika W. Walters
U.S. Geological Survey science for the Wyoming Landscape Conservation Initiative—2018 annual report 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)...
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 A. 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