Cory Overton
Cory Overton is a wildlife biologist at the Western Ecological Research Center.
Science and Products
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Dietary mercury exposure to endangered California Clapper Rails in San Francisco Bay
California Clapper Rails (Rallus longirostris obsoletus) are an endangered waterbird that forage in tidal-marsh habitats that pose risks from mercury exposure. We analyzed total mercury (Hg) in six macro-invertebrate and one fish species representing Clapper Rail diets from four tidal-marshes in San Francisco Bay, California. Mercury concentrations among individual taxa ranged from lowest at Colma
Authors
Michael L. Casazza, Mark A. Ricca, Cory T. Overton, John Y. Takekawa, Angela Merritt, Joshua T. Ackerman
Tidal and seasonal effects on survival rates of the endangered California clapper rail: Does invasive Spartina facilitate greater survival in a dynamic environment?
Invasive species frequently degrade habitats, disturb ecosystem processes, and can increase the likelihood of extinction of imperiled populations. However, novel or enhanced functions provided by invading species may reduce the impact of processes that limit populations. It is important to recognize how invasive species benefit endangered species to determine overall effects on sensitive ecosystem
Authors
Cory T. Overton, Michael L. Casazza, John Y. Takekawa, Donald R. Strong, Marcel Holyoak
Spatially explicit modeling of greater sage-grouse (Centrocercus urophasianus) habitat in Nevada and northeastern California: a decision-support tool for management
Greater sage-grouse (Centrocercus urophasianus, hereafter referred to as “sage-grouse”) populations are declining throughout the sagebrush (Artemisia spp.) ecosystem, including millions of acres of potential habitat across the West. Habitat maps derived from empirical data are needed given impending listing decisions that will affect both sage-grouse population dynamics and human land-use restrict
Authors
Peter S. Coates, Michael L. Casazza, Brianne E. Brussee, Mark A. Ricca, K. Benjamin Gustafson, Cory T. Overton, Erika Sanchez-Chopitea, Travis Kroger, Kimberly Mauch, Lara Niell, Kristy Howe, Scott Gardner, Shawn Espinosa, David J. Delehanty
Wetland Accretion Rate Model of Ecosystem Resilience (WARMER) and its application to habitat sustainability for endangered species in the San Francisco Estuary
Salt marsh faunas are constrained by specific habitat requirements for marsh elevation relative to sea level and tidal range. As sea level rises, changes in relative elevation of the marsh plain will have differing impacts on the availability of habitat for marsh obligate species. The Wetland Accretion Rate Model for Ecosystem Resilience (WARMER) is a 1-D model of elevation that incorporates both
Authors
Kathleen M. Swanson, Judith Z. Drexler, David H. Schoellhamer, Karen M. Thorne, Michael L. Casazza, Cory T. Overton, John C. Callaway, John Y. Takekawa
Final report for sea-level rise response modeling for San Francisco Bay estuary tidal marshes
The International Panel on Climate Change has identified coastal ecosystems as areas that will be disproportionally affected by climate change. Current sea-level rise projections range widely with 0.57 to 1.9 meters increase in mea sea level by 2100. The expected accelerated rate of sea-level rise through the 21st century will put many coastal ecosystems at risk, especially those in topographicall
Authors
John Y. Takekawa, Karen M. Thorne, Kevin Buffington, Kyle A. Spragens, Kathleen M. Swanson, Judith Z. Drexler, David H. Schoellhamer, Cory T. Overton, Michael L. Casazza
Hunting influences the diel patterns in habitat selection by northern pintails Anas acuta
Northern pintail Anas acuta (hereafter pintail) populations wintering within Suisun Marsh, a large estuarine managed wetland near San Francisco Bay, California,USA, have declined markedly over the last four decades. The reasons for this decline are unclear. Information on how hunting and other factors influence the selection of vegetation types and sanctuaries would be beneficial to manage pintail
Authors
Michael L. Casazza, Peter S. Coates, Michael R. Miller, Cory T. Overton, Daniel R. Yparraguirre
Does mercury contamination reduce body condition of endangered California clapper rails?
We examined mercury exposure in 133 endangered California clapper rails (Rallus longirostris obsoletus) within tidal marsh habitats of San Francisco Bay, California from 2006 to 2010. Mean total mercury concentrations were 0.56 μg/g ww in blood (range: 0.15–1.43), 9.87 μg/g fw in head feathers (3.37–22.0), 9.04 μg/g fw in breast feathers (3.68–20.2), and 0.57 μg/g fww in abandoned eggs (0.15–2.70)
Authors
Joshua T. Ackerman, Cory T. Overton, Michael L. Casazza, John Y. Takekawa, Collin A. Eagles-Smith, Robin A. Keister, Mark P. Herzog
Science in the Public Sphere: Greater Sage-grouse Conservation Planning from a Transdisciplinary Perspective
Integration of scientific data and adaptive management techniques is critical to the success of species conservation, however, there are uncertainties about effective methods of knowledge exchange between scientists and decisionmakers. The conservation planning and implementation process for Greater Sage-grouse (Centrocercus urophasianus; ) in the Mono Basin, Calif. region, was used as a case stud
Authors
Alicia Torregrosa, Michael L. Casazza, Margaret R. Caldwell, Teresa A. Mathiasmeier, Peter M. Morgan, Cory T. Overton
Scale-dependent associations of Band-tailed Pigeon counts at mineral sites
The abundance of Band-tailed Pigeons (Patagioenas fasciata monilis) has declined substantially from historic numbers along the Pacific Coast. Identification of patterns and causative factors of this decline are hampered because habitat use data are limited, and temporal and spatial variability patterns associated with population indices are not known. Furthermore, counts are influenced not only by
Authors
Cory T. Overton, Michael L. Casazza, Peter S. Coates
Ecology of Greater Sage-Grouse in the Bi-State Planning Area Final Report, September 2007
Conservation efforts for greater sage-grouse (Centrocercus urophasianus), hereafter sage-grouse, are underway across the range of this species. Over 70 local working groups have been established and are implementing on-the-ground sage-grouse oriented conservation projects. Early on in this process, the California Department of Fish and Game (CDFG) recognized the need to join in these efforts and r
Authors
Michael L. Casazza, Cory T. Overton, Melissa A. Farinha, Alicia Torregrosa, Joseph P. Fleskes, Michael R. Miller, James S. Sedinger, Eric J. Kolada
Sexing California Clapper Rails using morphological measurements
California Clapper Rails (Rallus longirostris obsoletus) have monomorphic plumage, a trait that makes identification of sex difficult without extensive behavioral observation or genetic testing. Using 31 Clapper Rails (22 females, 9 males), caught in south San Francisco Bay, CA, and using easily measurable morphological characteristics, we developed a discriminant function to distinguish sex. We t
Authors
Cory T. Overton, Michael L. Casazza, John Y. Takekawa, Tobias M. Rohmer
The California Clapper Rail and multispecies recovery planning
The California clapper rail (Rallus longirostris obsoletus) lives in remnant tidal marshes of San Francisco Bay, where less than 20 percent of the historic tidal wetlands remain. Listed as an endangered species in 1970 by the Fish and Wildlife Service (FWS), this enigmatic bird faces a myriad of threats, including habitat loss due to urban encroachment, sea-level rise caused by climate change, alt
Authors
Michael L. Casazza, Cory T. Overton, Melissa A. Farinha, John Y. Takekawa, Tobias M. Rohmer
Science and Products
Filter Total Items: 19
No Result Found
Filter Total Items: 51
Dietary mercury exposure to endangered California Clapper Rails in San Francisco Bay
California Clapper Rails (Rallus longirostris obsoletus) are an endangered waterbird that forage in tidal-marsh habitats that pose risks from mercury exposure. We analyzed total mercury (Hg) in six macro-invertebrate and one fish species representing Clapper Rail diets from four tidal-marshes in San Francisco Bay, California. Mercury concentrations among individual taxa ranged from lowest at Colma
Authors
Michael L. Casazza, Mark A. Ricca, Cory T. Overton, John Y. Takekawa, Angela Merritt, Joshua T. Ackerman
Tidal and seasonal effects on survival rates of the endangered California clapper rail: Does invasive Spartina facilitate greater survival in a dynamic environment?
Invasive species frequently degrade habitats, disturb ecosystem processes, and can increase the likelihood of extinction of imperiled populations. However, novel or enhanced functions provided by invading species may reduce the impact of processes that limit populations. It is important to recognize how invasive species benefit endangered species to determine overall effects on sensitive ecosystem
Authors
Cory T. Overton, Michael L. Casazza, John Y. Takekawa, Donald R. Strong, Marcel Holyoak
Spatially explicit modeling of greater sage-grouse (Centrocercus urophasianus) habitat in Nevada and northeastern California: a decision-support tool for management
Greater sage-grouse (Centrocercus urophasianus, hereafter referred to as “sage-grouse”) populations are declining throughout the sagebrush (Artemisia spp.) ecosystem, including millions of acres of potential habitat across the West. Habitat maps derived from empirical data are needed given impending listing decisions that will affect both sage-grouse population dynamics and human land-use restrict
Authors
Peter S. Coates, Michael L. Casazza, Brianne E. Brussee, Mark A. Ricca, K. Benjamin Gustafson, Cory T. Overton, Erika Sanchez-Chopitea, Travis Kroger, Kimberly Mauch, Lara Niell, Kristy Howe, Scott Gardner, Shawn Espinosa, David J. Delehanty
Wetland Accretion Rate Model of Ecosystem Resilience (WARMER) and its application to habitat sustainability for endangered species in the San Francisco Estuary
Salt marsh faunas are constrained by specific habitat requirements for marsh elevation relative to sea level and tidal range. As sea level rises, changes in relative elevation of the marsh plain will have differing impacts on the availability of habitat for marsh obligate species. The Wetland Accretion Rate Model for Ecosystem Resilience (WARMER) is a 1-D model of elevation that incorporates both
Authors
Kathleen M. Swanson, Judith Z. Drexler, David H. Schoellhamer, Karen M. Thorne, Michael L. Casazza, Cory T. Overton, John C. Callaway, John Y. Takekawa
Final report for sea-level rise response modeling for San Francisco Bay estuary tidal marshes
The International Panel on Climate Change has identified coastal ecosystems as areas that will be disproportionally affected by climate change. Current sea-level rise projections range widely with 0.57 to 1.9 meters increase in mea sea level by 2100. The expected accelerated rate of sea-level rise through the 21st century will put many coastal ecosystems at risk, especially those in topographicall
Authors
John Y. Takekawa, Karen M. Thorne, Kevin Buffington, Kyle A. Spragens, Kathleen M. Swanson, Judith Z. Drexler, David H. Schoellhamer, Cory T. Overton, Michael L. Casazza
Hunting influences the diel patterns in habitat selection by northern pintails Anas acuta
Northern pintail Anas acuta (hereafter pintail) populations wintering within Suisun Marsh, a large estuarine managed wetland near San Francisco Bay, California,USA, have declined markedly over the last four decades. The reasons for this decline are unclear. Information on how hunting and other factors influence the selection of vegetation types and sanctuaries would be beneficial to manage pintail
Authors
Michael L. Casazza, Peter S. Coates, Michael R. Miller, Cory T. Overton, Daniel R. Yparraguirre
Does mercury contamination reduce body condition of endangered California clapper rails?
We examined mercury exposure in 133 endangered California clapper rails (Rallus longirostris obsoletus) within tidal marsh habitats of San Francisco Bay, California from 2006 to 2010. Mean total mercury concentrations were 0.56 μg/g ww in blood (range: 0.15–1.43), 9.87 μg/g fw in head feathers (3.37–22.0), 9.04 μg/g fw in breast feathers (3.68–20.2), and 0.57 μg/g fww in abandoned eggs (0.15–2.70)
Authors
Joshua T. Ackerman, Cory T. Overton, Michael L. Casazza, John Y. Takekawa, Collin A. Eagles-Smith, Robin A. Keister, Mark P. Herzog
Science in the Public Sphere: Greater Sage-grouse Conservation Planning from a Transdisciplinary Perspective
Integration of scientific data and adaptive management techniques is critical to the success of species conservation, however, there are uncertainties about effective methods of knowledge exchange between scientists and decisionmakers. The conservation planning and implementation process for Greater Sage-grouse (Centrocercus urophasianus; ) in the Mono Basin, Calif. region, was used as a case stud
Authors
Alicia Torregrosa, Michael L. Casazza, Margaret R. Caldwell, Teresa A. Mathiasmeier, Peter M. Morgan, Cory T. Overton
Scale-dependent associations of Band-tailed Pigeon counts at mineral sites
The abundance of Band-tailed Pigeons (Patagioenas fasciata monilis) has declined substantially from historic numbers along the Pacific Coast. Identification of patterns and causative factors of this decline are hampered because habitat use data are limited, and temporal and spatial variability patterns associated with population indices are not known. Furthermore, counts are influenced not only by
Authors
Cory T. Overton, Michael L. Casazza, Peter S. Coates
Ecology of Greater Sage-Grouse in the Bi-State Planning Area Final Report, September 2007
Conservation efforts for greater sage-grouse (Centrocercus urophasianus), hereafter sage-grouse, are underway across the range of this species. Over 70 local working groups have been established and are implementing on-the-ground sage-grouse oriented conservation projects. Early on in this process, the California Department of Fish and Game (CDFG) recognized the need to join in these efforts and r
Authors
Michael L. Casazza, Cory T. Overton, Melissa A. Farinha, Alicia Torregrosa, Joseph P. Fleskes, Michael R. Miller, James S. Sedinger, Eric J. Kolada
Sexing California Clapper Rails using morphological measurements
California Clapper Rails (Rallus longirostris obsoletus) have monomorphic plumage, a trait that makes identification of sex difficult without extensive behavioral observation or genetic testing. Using 31 Clapper Rails (22 females, 9 males), caught in south San Francisco Bay, CA, and using easily measurable morphological characteristics, we developed a discriminant function to distinguish sex. We t
Authors
Cory T. Overton, Michael L. Casazza, John Y. Takekawa, Tobias M. Rohmer
The California Clapper Rail and multispecies recovery planning
The California clapper rail (Rallus longirostris obsoletus) lives in remnant tidal marshes of San Francisco Bay, where less than 20 percent of the historic tidal wetlands remain. Listed as an endangered species in 1970 by the Fish and Wildlife Service (FWS), this enigmatic bird faces a myriad of threats, including habitat loss due to urban encroachment, sea-level rise caused by climate change, alt
Authors
Michael L. Casazza, Cory T. Overton, Melissa A. Farinha, John Y. Takekawa, Tobias M. Rohmer