Bob Gresswell, Ph.D. (Former Employee)
Science and Products
Filter Total Items: 60
Aquatic invasive species: Lessons from cancer research
Aquatic invasive species are disrupting ecosystems with increasing frequency. Successful control of these invasions has been rare: Biologists and managers have few tools for fighting aquatic invaders. In contrast, the medical community has long worked to develop tools for preventing and fighting cancer. Its successes are marked by a coordinated research approach with multiple steps: prevention, ea
Authors
Adam J. Sepulveda, Andrew Ray, Robert K. Al-Chokhachy, Clint C. Muhlfeld, Robert E. Gresswell, Jackson A. Gross, Jeffrey L. Kershner
Thermal controls of Yellowstone cutthroat trout and invasive fishes under climate change
We combine large observed data sets and dynamically downscaled climate data to explore historic and future (2050–2069) stream temperature changes over the topographically diverse Greater Yellowstone Ecosystem (elevation range = 824–4017 m). We link future stream temperatures with fish growth models to investigate how changing thermal regimes could influence the future distribution and persistence
Authors
Robert K. Al-Chokhachy, Jay R. Alder, Steven W. Hostetler, Robert E. Gresswell, Bradley Shepard
Genetic variation reveals influence of landscape connectivity on population dynamics and resiliency of western trout in disturbance-prone habitats
Salmonid fishes have evolved and persisted in dynamic ecosystems where disturbance events vary in frequency, magnitude, timing, and duration, as well as the specific nature of associated effects (e.g., changes in thermal or flow regimes, geomorphology, or water chemistry). In the western United States, one of the major drivers of disturbance in stream ecosystems is fire. Although there is a growin
Authors
Helen M. Neville, Robert E. Gresswell, Jason B. Dunham
Incorporating spatial context into the analysis of salmonid habitat relations
In this response to the chapter by Lapointe (this volume), we discuss the question of why it is so difficult to predict salmonid-habitat relations in gravel-bed rivers and streams. We acknowledge that this cannot be an exhaustive treatment of the subject and, thus, identify what we believe are several key issues that demonstrate the necessity of incorporating spatial context into the analysis of f
Authors
Christian E. Torgersen, Colden V. Baxter, J. L. Ebersole, Bob Gresswell
Twenty Years After the 1988 Yellowstone Fires: Lessons About Disturbance and Ecosystems
The 1988 Yellowstone fires were among the first in what has proven to be an upsurge in large severe fires in the western USA during the past 20 years. At the time of the fires, little was known about the impacts of such a large severe disturbance because scientists had had few previous opportunities to study such an event. Ecologists predicted short- and long-term effects of the 1988 fires on vege
Authors
W.H. Romme, M.S. Boyce, R. Gresswell, E.H. Merrill, G.W. Minshall, C. Whitlock, M.G. Turner
Biology, status, and management of the yellowstone cutthroat trout
Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri were historically distributed in the Yellowstone River drainage (Montana and Wyoming) and the Snake River drainage (Wyoming, Idaho, Utah, Nevada, and probably Washington). Individual populations evolved distinct life history characteristics in response to the diverse environments in which they were isolated after the last glaciation. Anthro
Authors
Robert E. Gresswell
The 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 anthro
Authors
A.L. Haak, J.E. Williams, D. Isaak, A. Todd, C.C. Muhlfeld, J. L. Kershner, R. E. Gresswell, S. W. Hostetler, H.M. Neville
Factors influencing coastal cutthroat trout (Oncorhynchus clarkii clarkii) seasonal survival rates: A spatially continuous approach within stream networks
Mark-recapture methods were used to examine watershed-scale survival of coastal cutthroat trout (Oncorhynchus clarkii clarkii) from two headwater stream networks. A total of 1725 individuals (???100 mm, fork length) were individually marked and monitored seasonally over a 3-year period. Differences in survival were compared among spatial (stream segment, subwatershed, and watershed) and temporal (
Authors
A.M. Berger, R. E. Gresswell
Landscape-scale evaluation of genetic structure among barrier-isolated populations of coastal cutthroat trout, Oncorhynchus clarkii clarkii
Relationships among landscape structure, stochastic disturbance, and genetic diversity were assessed by examining interactions between watershed-scale environmental factors and genetic diversity of coastal cutthroat trout (Oncorhynchus clarkii clarkii) in 27 barrier-isolated watersheds from western Oregon, USA. Headwater populations of coastal cutthroat trout were genetically differentiated (mean
Authors
T.J. Guy, R. E. Gresswell, M. A. Banks
Longitudinal patterns of fish assemblages, aquatic habitat, and water temperature in the Lower Crooked River, Oregon
The Lower Crooked River is a remarkable groundwater-fed stream flowing through vertical basalt canyons in the Deschutes River Valley ecoregion in central Oregon (Pater and others, 1998). The 9-mile section of the river between the Crooked River National Grasslands boundary near Ogden Wayside and river mile (RM) 8 is protected under the National Wild and Scenic Rivers Act (16 U.S.C. 1271-1287) for
Authors
Christian E. Torgersen, David P. Hockman-Wert, Douglas S. Bateman, David W. Leer, Robert E. Gresswell
Use of seasonal freshwater wetlands by fishes in a temperate river floodplain
This study examined the use of freshwater wetland restoration and enhancement projects (i.e. non-estuarine wetlands subject to seasonal drying) by fish populations. To quantify fish use of freshwater emergent wetlands and assess the effect of wetland enhancement (i.e. addition of water control structures), two enhanced and two unenhanced emergent wetlands were compared, as well as two oxbow habita
Authors
Julie A. Henning, Robert E. Gresswell, Ian A. Fleming
Population-scale movement of coastal cutthroat trout in a naturally isolated stream network
To identify population‐scale patterns of movement, coastal cutthroat trout Oncorhynchus clarkii clarkii tagged and marked (35 radio‐tagged, 749 passive integrated transponder [PIT]‐tagged, and 3,025 fin‐clipped) were monitored from June 1999 to August 2000. The study watershed, located in western Oregon, was above a natural barrier to upstream movement. Emigration out of the watershed was estimate
Authors
R. E. Gresswell, S.R. Hendricks
Science and Products
Filter Total Items: 60
Aquatic invasive species: Lessons from cancer research
Aquatic invasive species are disrupting ecosystems with increasing frequency. Successful control of these invasions has been rare: Biologists and managers have few tools for fighting aquatic invaders. In contrast, the medical community has long worked to develop tools for preventing and fighting cancer. Its successes are marked by a coordinated research approach with multiple steps: prevention, ea
Authors
Adam J. Sepulveda, Andrew Ray, Robert K. Al-Chokhachy, Clint C. Muhlfeld, Robert E. Gresswell, Jackson A. Gross, Jeffrey L. Kershner
Thermal controls of Yellowstone cutthroat trout and invasive fishes under climate change
We combine large observed data sets and dynamically downscaled climate data to explore historic and future (2050–2069) stream temperature changes over the topographically diverse Greater Yellowstone Ecosystem (elevation range = 824–4017 m). We link future stream temperatures with fish growth models to investigate how changing thermal regimes could influence the future distribution and persistence
Authors
Robert K. Al-Chokhachy, Jay R. Alder, Steven W. Hostetler, Robert E. Gresswell, Bradley Shepard
Genetic variation reveals influence of landscape connectivity on population dynamics and resiliency of western trout in disturbance-prone habitats
Salmonid fishes have evolved and persisted in dynamic ecosystems where disturbance events vary in frequency, magnitude, timing, and duration, as well as the specific nature of associated effects (e.g., changes in thermal or flow regimes, geomorphology, or water chemistry). In the western United States, one of the major drivers of disturbance in stream ecosystems is fire. Although there is a growin
Authors
Helen M. Neville, Robert E. Gresswell, Jason B. Dunham
Incorporating spatial context into the analysis of salmonid habitat relations
In this response to the chapter by Lapointe (this volume), we discuss the question of why it is so difficult to predict salmonid-habitat relations in gravel-bed rivers and streams. We acknowledge that this cannot be an exhaustive treatment of the subject and, thus, identify what we believe are several key issues that demonstrate the necessity of incorporating spatial context into the analysis of f
Authors
Christian E. Torgersen, Colden V. Baxter, J. L. Ebersole, Bob Gresswell
Twenty Years After the 1988 Yellowstone Fires: Lessons About Disturbance and Ecosystems
The 1988 Yellowstone fires were among the first in what has proven to be an upsurge in large severe fires in the western USA during the past 20 years. At the time of the fires, little was known about the impacts of such a large severe disturbance because scientists had had few previous opportunities to study such an event. Ecologists predicted short- and long-term effects of the 1988 fires on vege
Authors
W.H. Romme, M.S. Boyce, R. Gresswell, E.H. Merrill, G.W. Minshall, C. Whitlock, M.G. Turner
Biology, status, and management of the yellowstone cutthroat trout
Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri were historically distributed in the Yellowstone River drainage (Montana and Wyoming) and the Snake River drainage (Wyoming, Idaho, Utah, Nevada, and probably Washington). Individual populations evolved distinct life history characteristics in response to the diverse environments in which they were isolated after the last glaciation. Anthro
Authors
Robert E. Gresswell
The 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 anthro
Authors
A.L. Haak, J.E. Williams, D. Isaak, A. Todd, C.C. Muhlfeld, J. L. Kershner, R. E. Gresswell, S. W. Hostetler, H.M. Neville
Factors influencing coastal cutthroat trout (Oncorhynchus clarkii clarkii) seasonal survival rates: A spatially continuous approach within stream networks
Mark-recapture methods were used to examine watershed-scale survival of coastal cutthroat trout (Oncorhynchus clarkii clarkii) from two headwater stream networks. A total of 1725 individuals (???100 mm, fork length) were individually marked and monitored seasonally over a 3-year period. Differences in survival were compared among spatial (stream segment, subwatershed, and watershed) and temporal (
Authors
A.M. Berger, R. E. Gresswell
Landscape-scale evaluation of genetic structure among barrier-isolated populations of coastal cutthroat trout, Oncorhynchus clarkii clarkii
Relationships among landscape structure, stochastic disturbance, and genetic diversity were assessed by examining interactions between watershed-scale environmental factors and genetic diversity of coastal cutthroat trout (Oncorhynchus clarkii clarkii) in 27 barrier-isolated watersheds from western Oregon, USA. Headwater populations of coastal cutthroat trout were genetically differentiated (mean
Authors
T.J. Guy, R. E. Gresswell, M. A. Banks
Longitudinal patterns of fish assemblages, aquatic habitat, and water temperature in the Lower Crooked River, Oregon
The Lower Crooked River is a remarkable groundwater-fed stream flowing through vertical basalt canyons in the Deschutes River Valley ecoregion in central Oregon (Pater and others, 1998). The 9-mile section of the river between the Crooked River National Grasslands boundary near Ogden Wayside and river mile (RM) 8 is protected under the National Wild and Scenic Rivers Act (16 U.S.C. 1271-1287) for
Authors
Christian E. Torgersen, David P. Hockman-Wert, Douglas S. Bateman, David W. Leer, Robert E. Gresswell
Use of seasonal freshwater wetlands by fishes in a temperate river floodplain
This study examined the use of freshwater wetland restoration and enhancement projects (i.e. non-estuarine wetlands subject to seasonal drying) by fish populations. To quantify fish use of freshwater emergent wetlands and assess the effect of wetland enhancement (i.e. addition of water control structures), two enhanced and two unenhanced emergent wetlands were compared, as well as two oxbow habita
Authors
Julie A. Henning, Robert E. Gresswell, Ian A. Fleming
Population-scale movement of coastal cutthroat trout in a naturally isolated stream network
To identify population‐scale patterns of movement, coastal cutthroat trout Oncorhynchus clarkii clarkii tagged and marked (35 radio‐tagged, 749 passive integrated transponder [PIT]‐tagged, and 3,025 fin‐clipped) were monitored from June 1999 to August 2000. The study watershed, located in western Oregon, was above a natural barrier to upstream movement. Emigration out of the watershed was estimate
Authors
R. E. Gresswell, S.R. Hendricks