Theodore Kennedy, Ph.D.
I use food webs to describe ecosystem response to river regulation and biological invasions. I have been with USGS since 2004, providing science in support of the Glen Canyon Dam Adaptive Management Program.
Professional Experience
11/04 - present: Research Ecologist, Grand Canyon Monitoring and Research Center, Southwest Biological Science Center, US Geological Survey, Flagstaff, AZ
1/04 - 11/04: Postdoctoral researcher, Arizona State University
1/03 - 1/04: Postdoctoral researcher, Grand Canyon Monitoring and Research Center, Southwest Biological Science Center, US Geological Survey, Flagstaff, AZ.
Education and Certifications
9/96 - 12/02: Ph.D. in Ecology, Dept. of Ecology, Evolution, and Behavior, University of Minnesota. Dissertation title: The causes and consequences of plant invasions
1/90 - 12/94: B.S. in Ecology, California Polytechnic State University at San Luis Obispo, cum laude.
Science and Products
Filter Total Items: 15
No Result Found
Filter Total Items: 64
Warm water temperatures and shifts in seasonality increase trout recruitment but only moderately decrease adult size in western North American tailwaters Warm water temperatures and shifts in seasonality increase trout recruitment but only moderately decrease adult size in western North American tailwaters
Dams throughout western North America have altered thermal regimes in rivers, creating cold, clear “tailwaters” in which trout populations thrive. Ongoing drought in the region has led to highly publicized reductions in reservoir storage and raised concerns about potential reductions in downstream flows. Large changes in riverine thermal regimes may also occur as reservoir water levels...
Authors
Kimberly L. Dibble, Charles B. Yackulic, Theodore A. Kennedy
Brown trout in the Lees Ferry reach of the Colorado River—Evaluation of causal hypotheses and potential interventions Brown trout in the Lees Ferry reach of the Colorado River—Evaluation of causal hypotheses and potential interventions
Over the period 2014–2016, the number of nonnative brown trout (Salmo trutta) captured during routine monitoring in the Lees Ferry reach of the Colorado River, downstream of Glen Canyon Dam, began increasing. Management agencies and stakeholders have questioned whether the increase in brown trout in the Lees Ferry reach represents a threat to the endangered humpback chub (Gila cypha), to...
Authors
Michael C. Runge, Charles B. Yackulic, Lucas S. Bair, Theodore A. Kennedy, Richard A. Valdez, Craig Ellsworth, Jeffrey L. Kershner, R. Scott Rogers, Melissa A. Trammell, Kirk L. Young
Pulsed flows, tributary inputs, and food web structure in a highly regulated river Pulsed flows, tributary inputs, and food web structure in a highly regulated river
1.Dams disrupt the river continuum, altering hydrology, biodiversity, and energy flow. Although research indicates that tributary inputs have the potential to dilute these effects, knowledge at the food web level is still scarce. 2.Here we examined the riverine food web structure of the Colorado River below Glen Canyon Dam, focusing on organic matter sources, trophic diversity, and food...
Authors
John Sabo, Melanie Caron, Richard R. Doucett, Kimberly L. Dibble, Albert Ruhi, Jane Marks, Bruce Hungate, Theodore A. Kennedy
Meeting the challenge of interacting threats in freshwater ecosystems: A call to scientists and managers Meeting the challenge of interacting threats in freshwater ecosystems: A call to scientists and managers
Human activities create threats that have consequences for freshwater ecosystems and, in most watersheds, observed ecological responses are the result of complex interactions among multiple threats and their associated ecological alterations. Here we discuss the value of considering multiple threats in research and management, offer suggestions for filling knowledge gaps, and provide...
Authors
Laura S. Craig, Julian D. Olden, Angela Arthington, Sally Entrekin, Charles P. Hawkins, John J. Kelly, Theodore A. Kennedy, Bryan M. Maitland, Emma J. Rosi, Allison H. Roy, David L. Strayer, Jennifer L. Tank, Amie O. West, Matthew S. Wooten
A coupled metabolic-hydraulic model and calibration scheme for estimating of whole-river metabolism during dynamic flow conditions A coupled metabolic-hydraulic model and calibration scheme for estimating of whole-river metabolism during dynamic flow conditions
Conventional methods for estimating whole-stream metabolic rates from measured dissolved oxygen dynamics do not account for the variation in solute transport times created by dynamic flow conditions. Changes in flow at hourly time scales are common downstream of hydroelectric dams (i.e. hydropeaking), and hydrologic limitations of conventional metabolic models have resulted in a poor
Authors
Robert A. Payn, Robert O Hall, Theodore A. Kennedy, Geoff C Poole, Lucy A. Marshall
Trends in Rainbow Trout recruitment, abundance, survival, and growth during a boom-and-bust cycle in a tailwater fishery Trends in Rainbow Trout recruitment, abundance, survival, and growth during a boom-and-bust cycle in a tailwater fishery
Data from a large-scale mark-recapture study was used in an open population model to determine the cause for long-term trends in growth and abundance of a Rainbow Trout Oncorhynchus mykiss population in the tailwater of Glen Canyon Dam, AZ. Reduced growth affected multiple life stages and processes causing negative feedbacks that regulated the abundance of the population, including...
Authors
Josh Korman, Micheal D. Yard, Theodore A. Kennedy
Deleterious effects of net clogging on the quantification of stream drift Deleterious effects of net clogging on the quantification of stream drift
Drift studies are central to stream and river ecological research. However, a fundamental aspect of quantifying drift — how net clogging affects the accuracy of results — has been widely ignored. Utilizing approaches from plankton and suspended sediment studies in oceanography and hydrology, we examined the rate and dynamics of net clogging across a range of conditions. We found that...
Authors
Jeffrey D. Muehlbauer, Theodore A. Kennedy, Adam J. Copp, Thomas A. Sabol
Scientific monitoring plan in support of the selected alternative of the Glen Canyon Dam Long-Term Experimental and Management Plan Scientific monitoring plan in support of the selected alternative of the Glen Canyon Dam Long-Term Experimental and Management Plan
Introduction The purpose of this document is to describe a strategy by which monitoring and research data in the natural and social sciences will be collected, analyzed, and provided to the U.S. Department of the Interior (DOI), its bureaus, and to the Glen Canyon Dam Adaptive Management Program (GCDAMP) in support of implementation of the Glen Canyon Dam Long-Term Experimental and...
Authors
Scott P. Vanderkooi, Theodore A. Kennedy, David J. Topping, Paul E. Grams, David L. Ward, Helen C. Fairley, Lucas S. Bair, Joel B. Sankey, John C. Schmidt, Charles B. Yackulic
Water clarity of the Colorado River—Implications for food webs and fish communities Water clarity of the Colorado River—Implications for food webs and fish communities
The closure of Glen Canyon Dam in 1963 resulted in drastic changes to water clarity, temperature, and flow of the Colorado River in Glen, Marble, and Grand Canyons. The Colorado River is now much clearer, water temperature is less variable throughout the year, and the river is much colder in the summer months. The flow—regulated by the dam—is now less variable annually, but has larger...
Authors
Nicholas Voichick, Theodore A. Kennedy, David J. Topping, Ronald E. Griffiths, Kyrie Fry
Phenology of the adult angel lichen moth (Cisthene angelus) in Grand Canyon, USA Phenology of the adult angel lichen moth (Cisthene angelus) in Grand Canyon, USA
We investigated the phenology of adult angel lichen moths (Cisthene angelus) along a 364-km long segment of the Colorado River in Grand Canyon, Arizona, USA, using a unique data set of 2,437 light-trap samples collected by citizen scientists. We found that adults of C. angelus were bivoltine from 2012 to 2014. We quantified plasticity in wing lengths and sex ratios among the two...
Authors
Anya N. Metcalfe, Theodore A. Kennedy, Jeffrey D. Muehlbauer
Flow management for hydropower extirpates aquatic insects, undermining river food webs Flow management for hydropower extirpates aquatic insects, undermining river food webs
Dams impound the majority of rivers and provide important societal benefits, especially daily water releases that enable on-peak hydroelectricity generation. Such “hydropeaking” is common worldwide, but its downstream impacts remain unclear. We evaluated the response of aquatic insects, a cornerstone of river food webs, to hydropeaking using a life history–hydrodynamic model. Our model...
Authors
Theodore A. Kennedy, Jeffrey D. Muehlbauer, Charles B. Yackulic, D.A. Lytle, S.A. Miller, Kimberly L. Dibble, Eric W. Kortenhoeven, Anya N. Metcalfe, Colden V. Baxter
Prey size and availability limits maximum size of rainbow trout in a large tailwater: insights from a drift-foraging bioenergetics model Prey size and availability limits maximum size of rainbow trout in a large tailwater: insights from a drift-foraging bioenergetics model
The cold and clear water conditions present below many large dams create ideal conditions for the development of economically important salmonid fisheries. Many of these tailwater fisheries have experienced declines in the abundance and condition of large trout species, yet the causes of these declines remain uncertain. Here, we develop, assess, and apply a drift-foraging bioenergetics...
Authors
Michael J. Dodrill, Charles B. Yackulic, Theodore A. Kennedy, John W Haye
Non-USGS Publications**
Kennedy, T.A., 1998, Patterns of an invasion by Argentine ants (Linepithema humile) in a riparian corridor and its effects on ant diversity: The American Midland Naturalist, v. 140, p. 343-350.
Naeem, S., Knops, J.M., Tilman, D., Howe, K.M., Kennedy, T. and Gale, S., 2000, Plant diversity increases resistance to invasion in the absence of covarying extrinsic factors: Oikos, v. 91, p. 97-108, DOI: 10.1034/j.1600-0706.2000.910108.x.
Raffaelli, D., Van der Putten, W.H., Persson, L., Wardle, D.A., Petchey, O.L., Koricheva, J., Van Der Heijden, M., Mikola, J. and Kennedy, T., 2002, Multi-trophic dynamics and ecosystem processes, In Loreau, M., Naeem, S., and Inchausti, P., eds., Biodiversity and ecosystem functioning: synthesis and perspectives: Oxford, Oxford University Press, p.147-154.
Levine, J.M., Kennedy, T., and Naeem, S., 2002, Neighborhood scale effects of species diversity on biological invasions and their relationship to community patterns, In Loreau, M., Naeem, S., and Inchausti, P., eds., Biodiversity and ecosystem functioning: synthesis and perspectives: Oxford, Oxford University Press, p.114-124.
Kennedy, T.A., Naeem, S., Howe, K.M., Knops, J.M., Tilman, D., and Reich, P., 2002, Biodiversity as a barrier to ecological invasion. Nature, v.417, p.636. doi:10.1038/nature00776.
Kennedy, T.A., and Hobbie, S.E., 2004, Saltcedar (Tamarix ramosissima) invasion alters organic matter dynamics in a desert stream. Freshwater Biology, v. 49, p. 65-76. doi: 10.1046/j.1365-2426.2003.01166.x.
Kennedy, T.A., Finlay, J.C., and Hobbie, S.E., 2005, Eradication of invasive Tamarix ramosissima along a desert stream increases native fish density: Ecological Applications, v. 15, p. 2072-2083.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 15
No Result Found
Filter Total Items: 64
Warm water temperatures and shifts in seasonality increase trout recruitment but only moderately decrease adult size in western North American tailwaters Warm water temperatures and shifts in seasonality increase trout recruitment but only moderately decrease adult size in western North American tailwaters
Dams throughout western North America have altered thermal regimes in rivers, creating cold, clear “tailwaters” in which trout populations thrive. Ongoing drought in the region has led to highly publicized reductions in reservoir storage and raised concerns about potential reductions in downstream flows. Large changes in riverine thermal regimes may also occur as reservoir water levels...
Authors
Kimberly L. Dibble, Charles B. Yackulic, Theodore A. Kennedy
Brown trout in the Lees Ferry reach of the Colorado River—Evaluation of causal hypotheses and potential interventions Brown trout in the Lees Ferry reach of the Colorado River—Evaluation of causal hypotheses and potential interventions
Over the period 2014–2016, the number of nonnative brown trout (Salmo trutta) captured during routine monitoring in the Lees Ferry reach of the Colorado River, downstream of Glen Canyon Dam, began increasing. Management agencies and stakeholders have questioned whether the increase in brown trout in the Lees Ferry reach represents a threat to the endangered humpback chub (Gila cypha), to...
Authors
Michael C. Runge, Charles B. Yackulic, Lucas S. Bair, Theodore A. Kennedy, Richard A. Valdez, Craig Ellsworth, Jeffrey L. Kershner, R. Scott Rogers, Melissa A. Trammell, Kirk L. Young
Pulsed flows, tributary inputs, and food web structure in a highly regulated river Pulsed flows, tributary inputs, and food web structure in a highly regulated river
1.Dams disrupt the river continuum, altering hydrology, biodiversity, and energy flow. Although research indicates that tributary inputs have the potential to dilute these effects, knowledge at the food web level is still scarce. 2.Here we examined the riverine food web structure of the Colorado River below Glen Canyon Dam, focusing on organic matter sources, trophic diversity, and food...
Authors
John Sabo, Melanie Caron, Richard R. Doucett, Kimberly L. Dibble, Albert Ruhi, Jane Marks, Bruce Hungate, Theodore A. Kennedy
Meeting the challenge of interacting threats in freshwater ecosystems: A call to scientists and managers Meeting the challenge of interacting threats in freshwater ecosystems: A call to scientists and managers
Human activities create threats that have consequences for freshwater ecosystems and, in most watersheds, observed ecological responses are the result of complex interactions among multiple threats and their associated ecological alterations. Here we discuss the value of considering multiple threats in research and management, offer suggestions for filling knowledge gaps, and provide...
Authors
Laura S. Craig, Julian D. Olden, Angela Arthington, Sally Entrekin, Charles P. Hawkins, John J. Kelly, Theodore A. Kennedy, Bryan M. Maitland, Emma J. Rosi, Allison H. Roy, David L. Strayer, Jennifer L. Tank, Amie O. West, Matthew S. Wooten
A coupled metabolic-hydraulic model and calibration scheme for estimating of whole-river metabolism during dynamic flow conditions A coupled metabolic-hydraulic model and calibration scheme for estimating of whole-river metabolism during dynamic flow conditions
Conventional methods for estimating whole-stream metabolic rates from measured dissolved oxygen dynamics do not account for the variation in solute transport times created by dynamic flow conditions. Changes in flow at hourly time scales are common downstream of hydroelectric dams (i.e. hydropeaking), and hydrologic limitations of conventional metabolic models have resulted in a poor
Authors
Robert A. Payn, Robert O Hall, Theodore A. Kennedy, Geoff C Poole, Lucy A. Marshall
Trends in Rainbow Trout recruitment, abundance, survival, and growth during a boom-and-bust cycle in a tailwater fishery Trends in Rainbow Trout recruitment, abundance, survival, and growth during a boom-and-bust cycle in a tailwater fishery
Data from a large-scale mark-recapture study was used in an open population model to determine the cause for long-term trends in growth and abundance of a Rainbow Trout Oncorhynchus mykiss population in the tailwater of Glen Canyon Dam, AZ. Reduced growth affected multiple life stages and processes causing negative feedbacks that regulated the abundance of the population, including...
Authors
Josh Korman, Micheal D. Yard, Theodore A. Kennedy
Deleterious effects of net clogging on the quantification of stream drift Deleterious effects of net clogging on the quantification of stream drift
Drift studies are central to stream and river ecological research. However, a fundamental aspect of quantifying drift — how net clogging affects the accuracy of results — has been widely ignored. Utilizing approaches from plankton and suspended sediment studies in oceanography and hydrology, we examined the rate and dynamics of net clogging across a range of conditions. We found that...
Authors
Jeffrey D. Muehlbauer, Theodore A. Kennedy, Adam J. Copp, Thomas A. Sabol
Scientific monitoring plan in support of the selected alternative of the Glen Canyon Dam Long-Term Experimental and Management Plan Scientific monitoring plan in support of the selected alternative of the Glen Canyon Dam Long-Term Experimental and Management Plan
Introduction The purpose of this document is to describe a strategy by which monitoring and research data in the natural and social sciences will be collected, analyzed, and provided to the U.S. Department of the Interior (DOI), its bureaus, and to the Glen Canyon Dam Adaptive Management Program (GCDAMP) in support of implementation of the Glen Canyon Dam Long-Term Experimental and...
Authors
Scott P. Vanderkooi, Theodore A. Kennedy, David J. Topping, Paul E. Grams, David L. Ward, Helen C. Fairley, Lucas S. Bair, Joel B. Sankey, John C. Schmidt, Charles B. Yackulic
Water clarity of the Colorado River—Implications for food webs and fish communities Water clarity of the Colorado River—Implications for food webs and fish communities
The closure of Glen Canyon Dam in 1963 resulted in drastic changes to water clarity, temperature, and flow of the Colorado River in Glen, Marble, and Grand Canyons. The Colorado River is now much clearer, water temperature is less variable throughout the year, and the river is much colder in the summer months. The flow—regulated by the dam—is now less variable annually, but has larger...
Authors
Nicholas Voichick, Theodore A. Kennedy, David J. Topping, Ronald E. Griffiths, Kyrie Fry
Phenology of the adult angel lichen moth (Cisthene angelus) in Grand Canyon, USA Phenology of the adult angel lichen moth (Cisthene angelus) in Grand Canyon, USA
We investigated the phenology of adult angel lichen moths (Cisthene angelus) along a 364-km long segment of the Colorado River in Grand Canyon, Arizona, USA, using a unique data set of 2,437 light-trap samples collected by citizen scientists. We found that adults of C. angelus were bivoltine from 2012 to 2014. We quantified plasticity in wing lengths and sex ratios among the two...
Authors
Anya N. Metcalfe, Theodore A. Kennedy, Jeffrey D. Muehlbauer
Flow management for hydropower extirpates aquatic insects, undermining river food webs Flow management for hydropower extirpates aquatic insects, undermining river food webs
Dams impound the majority of rivers and provide important societal benefits, especially daily water releases that enable on-peak hydroelectricity generation. Such “hydropeaking” is common worldwide, but its downstream impacts remain unclear. We evaluated the response of aquatic insects, a cornerstone of river food webs, to hydropeaking using a life history–hydrodynamic model. Our model...
Authors
Theodore A. Kennedy, Jeffrey D. Muehlbauer, Charles B. Yackulic, D.A. Lytle, S.A. Miller, Kimberly L. Dibble, Eric W. Kortenhoeven, Anya N. Metcalfe, Colden V. Baxter
Prey size and availability limits maximum size of rainbow trout in a large tailwater: insights from a drift-foraging bioenergetics model Prey size and availability limits maximum size of rainbow trout in a large tailwater: insights from a drift-foraging bioenergetics model
The cold and clear water conditions present below many large dams create ideal conditions for the development of economically important salmonid fisheries. Many of these tailwater fisheries have experienced declines in the abundance and condition of large trout species, yet the causes of these declines remain uncertain. Here, we develop, assess, and apply a drift-foraging bioenergetics...
Authors
Michael J. Dodrill, Charles B. Yackulic, Theodore A. Kennedy, John W Haye
Non-USGS Publications**
Kennedy, T.A., 1998, Patterns of an invasion by Argentine ants (Linepithema humile) in a riparian corridor and its effects on ant diversity: The American Midland Naturalist, v. 140, p. 343-350.
Naeem, S., Knops, J.M., Tilman, D., Howe, K.M., Kennedy, T. and Gale, S., 2000, Plant diversity increases resistance to invasion in the absence of covarying extrinsic factors: Oikos, v. 91, p. 97-108, DOI: 10.1034/j.1600-0706.2000.910108.x.
Raffaelli, D., Van der Putten, W.H., Persson, L., Wardle, D.A., Petchey, O.L., Koricheva, J., Van Der Heijden, M., Mikola, J. and Kennedy, T., 2002, Multi-trophic dynamics and ecosystem processes, In Loreau, M., Naeem, S., and Inchausti, P., eds., Biodiversity and ecosystem functioning: synthesis and perspectives: Oxford, Oxford University Press, p.147-154.
Levine, J.M., Kennedy, T., and Naeem, S., 2002, Neighborhood scale effects of species diversity on biological invasions and their relationship to community patterns, In Loreau, M., Naeem, S., and Inchausti, P., eds., Biodiversity and ecosystem functioning: synthesis and perspectives: Oxford, Oxford University Press, p.114-124.
Kennedy, T.A., Naeem, S., Howe, K.M., Knops, J.M., Tilman, D., and Reich, P., 2002, Biodiversity as a barrier to ecological invasion. Nature, v.417, p.636. doi:10.1038/nature00776.
Kennedy, T.A., and Hobbie, S.E., 2004, Saltcedar (Tamarix ramosissima) invasion alters organic matter dynamics in a desert stream. Freshwater Biology, v. 49, p. 65-76. doi: 10.1046/j.1365-2426.2003.01166.x.
Kennedy, T.A., Finlay, J.C., and Hobbie, S.E., 2005, Eradication of invasive Tamarix ramosissima along a desert stream increases native fish density: Ecological Applications, v. 15, p. 2072-2083.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.