Species We Study: Reptiles Active
By Species Management Research Program
September 27, 2022
Reptile intro
Reptiles Research
Reptiles Research
Filter Total Items: 30
Joint Ecosystem Modeling: Alligator Production Probability Model
Because the American alligator ( Alligator mississippiensis ) is a keystone species of the Everglades ecosystem, managers need a way to quantitatively assess the effects of alternative restoration scenarios on alligators.
Sea turtle nesting on Eglin Air Force Base property, Cape San Blas, Florida
The Northwestern Atlantic population of loggerhead sea turtles is one of the largest in the world. Genetic studies have divided this population into 5 management units including a genetically distinct group that nests throughout the northern Gulf of Mexico (GoM).
Ecology and Conservation of Sensitive Herpetofauna Species
Many species of amphibians and reptiles are declining or facing population threats in the West related to habitat loss, habitat alteration, introduction of non-native species, and other factors. Our work focuses on the status and trends of resident herpetofauna and how to better manage their habitats. Much of the effort is undertaken with cooperators, particularly with other agencies in the...
Ecology and Conservation of Reptiles
This project improves our understanding of the ecology of reptiles in California and evaluates methods of managing landscapes and these imperiled species. In particular, Dr. Brian Halstead examines the distribution and demography of reptiles to understand factors that affect where they are found and how populations change. He further explores the relationships of reptiles with their abiotic and...
Desert Tortoise Ecology, Health, Habitat, and Conservation Biology
The desert tortoise is listed as “threatened” under the Endangered Species Act. USGS WERC scientists, along with project partners have been conducting long-term analyses on how changes in the southwestern deserts of the United States can affect desert tortoise populations. Dr. Todd Esque and his team are investigating how habitat disturbances and restoration projects influence tortoise populations...
Reptile Biodiversity in the Pacific Basin Islands
Dr. Robert Fisher and his colleagues have teamed up with the U.S. Fish and Wildlife, The Nature Conservancy and multiple universities to conduct several types of studies that will address high priority issues related to reptiles in the Pacific Basin Islands. These studies will provide new information about species diversity, endemicity, biology and demography of reptile fauna and will lay the...
Relocating and Augmenting Desert Tortoise Populations
As resource managers balance the needs of humans and wildlife, WERC’s Dr. Berry provides the necessary science to inform decisions on shared lands. Visit the “Science” tab to delve into specific projects.
Human Influence on Desert Tortoise Habitats
The deserts of the Southwest are under increasing pressure from growing human communities. The spread of cities, agricultural fields, grazing livestock, power plants, and other forms of human development in the past and present have affected the region’s natural resources, including its wildlife. WERC’s Dr. Kristin Berry is studying the response of threatened desert tortoises to changing habitats...
Ecology and Biology of Desert Tortoises
WERC wildlife biologist Dr. Kristin Berry has more than forty years of experience studying Agassiz’s desert tortoise. As the lead on several USGS projects, Dr. Berry continues to lend her expertise to investigating the status, genetics, and behavior of Agassiz’s tortoise populations in the Mojave Desert.
Turtle Ecology
Turtles are among the most recognizable and iconic of animals. Any animal with a shell and a backbone is a turtle whether they are called turtles, tortoises, or terrapins. In fact, terrapin is an Algonquian Native American name for turtle. Worldwide there are 356 turtle species on all continents except for Antarctica. The United States has more species than any other country with about 62...
Giant Constrictor Snakes in Florida: A Sizeable Research Challenge
Since the mid-1990s, several species of non-native, giant constrictor snakes, such as Burmese pythons and boa constrictors, have surfaced in localities throughout southern Florida. Several are known or suspected to be breeding and appear to be spreading northward. Increasingly, media and other reports of sightings or encounters with these animals have emphasized the dangers they could impose on...
Population Biology and Ecology of Diamondback Terrapins in Mangrove Forested Ecosystems in the Greater Everglades
Long-term capture-recapture research in the Everglades National Park provides baseline information on the Diamondback Terrapin, a species that may be threatened by human disturbances.
Explore our science using the data below.
Recent publications (2020-2022) related to USGS reptile research are listed below. A complete listing of USGS reptile publications is available from the button below.
Filter Total Items: 23
Tropicalization of temperate ecosystems in North America: The northward range expansion of tropical organisms in response to warming winter temperatures
Tropicalization is a term used to describe the transformation of temperate ecosystems by poleward‐moving tropical organisms in response to warming temperatures. In North America, decreases in the frequency and intensity of extreme winter cold events are expected to allow the poleward range expansion of many cold‐sensitive tropical organisms, sometimes at the expense of temperate organisms. Althoug
Authors
Michael Osland, Philip Stevens, Margaret Lamont, Richard Brusca, Kristen Hart, Hardin Waddle, Catherine Langtimm, Caroline Williams, Barry Keim, Adam Terando, Eric Reyier, Katie Marshall, Michael E. Loik, Ross Boucek, Amanda Lewis, Jeffrey A. Seminoff
Environmental contamination and unusual snake mortality in an urban national wildlife refuge
The National Wildlife Refuge (NWR) System protects ~150 million acres of land and water in the United States and provides habitat for >2,000 native vertebrates species. Although legally protected, wildlife populations within these refuges can be threatened by anthropogenic activities. The lack of knowledge about such threats has the potential to undermine biodiversity conservation.
We investigate
Authors
Kimberly A. Terrell, Anne Ballmann, Ashli Brown, Christina Childers, Susan Knowles, Ashley Meredith, Darrell Sparks
Biological and habitat assessment of the Lower Rouge River, Michigan 2018
A key component of evaluating the success of habitat remediation projects is determining preremediation conditions, biotic and abiotic, to establish a baseline and compare with postproject conditions. The Rouge River, Michigan, is a Great Lakes Area of Concern with a listed Beneficial Use Impairment related to loss of fish and wildlife habitat. A biological and habitat assessment was completed in
Authors
Edward F. Roseman, Jason Fischer, Robin L. DeBruyne, Scott A. Jackson
Movement-assisted localization from acoustic telemetry data
Acoustic telemetry technologies are being increasingly deployed to study a variety of aquatic taxa including fishes, reptiles, and marine mammals. Large cooperative telemetry networks produce vast quantities of data useful in the study of movement, resource selection and species distribution. Efficient use of acoustic telemetry data requires estimation of acoustic source locations from detections
Authors
Nathan J. Hostetter, Andy Royle
Landscape dominance of introduced herpetofauna on an oceanic island
Habitat loss and fragmentation can negatively impact native wildlife and facilitate establishment
of introduced species. On islands, introduced species are a primary cause of
extinction and can alter community membership through predation or competition for
resources. Consequently, elucidating the distribution of introduced and native species can
improve understanding of the potential synergistic
Authors
Eric Thomas Hileman, Bradley A. Eichelberger, Jill Liske-Clark, Patrick D Barnhart, Robert Reed, Amy A. Yackel Adams, Melia G. Nafus
Herpetofauna occupancy and community composition along a tidal swamp salinity gradient
Occupancy patterns of herpetofauna in most tidal freshwater swamps are unknown. Tidal freshwater swamps currently face multiple threats, including salinization, which can influence their associated plant and animal communities. The impacts of salinization to herpetofauna communities in tidal freshwater swamps have not been assessed. To improve predictions regarding these herpetofauna, we conducted
Authors
Sidney T Godfrey, J. Hardin Waddle, Robert F Baldwin, William H. Conner, William C Bridges, Jamie A. Duberstein
Introgression obscures lineage boundaries and phylogeographic history in the western banded gecko, Coleonyx variegatus (Squamata: Eublepharidae)
The geomorphological formation of the Baja California peninsula and the Gulf of California is a principal driver of diversification for the reptiles of North America’s warm deserts. The western banded gecko, Coleonyx variegatus, is distributed throughout the Mojave, Sonoran and Peninsular deserts. In this study we use multilocus sequence data to address deep phylogeographic structure within C. var
Authors
Dean H Leavitt, Bradford Hollingsworth, Robert N. Fisher, Tod W Reeder
Shifts in hatching date of American crocodile (Crocodylus acutus) in southern Florida
Globally temperature of marine environments is on the rise and temperature plays an important role in the life-history of reptiles. In this study, we examined the relationship between sea surface temperature and average date of hatching for American crocodiles (Crocodylus acutus) over a 37-year period at two nesting sites, Everglades National Park and Florida Power and Light Turkey Point Power Pla
Authors
Michael Cherkiss, James I. Watling, Laura A. Brandt, Frank J. Mazzotti, Jim Linsay, Jeffrey S. Beauchamp, Jerome J. Lorenz, Joseph Wasilewski, Ikuko Fujisaki, Kristen Hart
Use of visual surveys and radiotelemetry reveals sources of detection bias for a cryptic snake at low densities
Transect surveys are frequently used to estimate distribution and abundance of species across a landscape, yet a proportion of individuals present will be missed because either they were out of view and unavailable for detection or they were available but not detected because the surveyors missed them. These situations lead to availability and perception bias, respectively, and can result in misle
Authors
SM Boback, Melia G. Nafus, Amy A. Yackel Adams, Robert Reed
Reptiles under the conservation umbrella of the greater sage‐grouse
In conservation paradigms, management actions for umbrella species also benefit co‐occurring species because of overlapping ranges and similar habitat associations. The greater sage‐grouse (Centrocercus urophasianus) is an umbrella species because it occurs across vast sagebrush ecosystems of western North America and is the recipient of extensive habitat conservation and restoration efforts that
Authors
David Pilliod, Michelle Jeffries, Robert Arkle, Deanna H. Olson
Pilot inventory of mammals, reptiles, and amphibians, Golden Gate National Recreation Area, California, 1990-1997
The United States Geological Survey Golden Gate Field Station conducted a baseline inventory of terrestrial vertebrates within the Golden Gate National Recreation Area (GGNRA), Marin, San Francisco, and San Mateo Counties, California between 1990 and 1997. We established 456 permanent study plots in 6 major park habitats, including grassland, coastal scrub, riparian woodland, coastal wetland, broa
Authors
Marcia Semenoff-Irving, Judd A. Howell
Reptile intro
Reptiles Research
Reptiles Research
Filter Total Items: 30
Joint Ecosystem Modeling: Alligator Production Probability Model
Because the American alligator ( Alligator mississippiensis ) is a keystone species of the Everglades ecosystem, managers need a way to quantitatively assess the effects of alternative restoration scenarios on alligators.
Sea turtle nesting on Eglin Air Force Base property, Cape San Blas, Florida
The Northwestern Atlantic population of loggerhead sea turtles is one of the largest in the world. Genetic studies have divided this population into 5 management units including a genetically distinct group that nests throughout the northern Gulf of Mexico (GoM).
Ecology and Conservation of Sensitive Herpetofauna Species
Many species of amphibians and reptiles are declining or facing population threats in the West related to habitat loss, habitat alteration, introduction of non-native species, and other factors. Our work focuses on the status and trends of resident herpetofauna and how to better manage their habitats. Much of the effort is undertaken with cooperators, particularly with other agencies in the...
Ecology and Conservation of Reptiles
This project improves our understanding of the ecology of reptiles in California and evaluates methods of managing landscapes and these imperiled species. In particular, Dr. Brian Halstead examines the distribution and demography of reptiles to understand factors that affect where they are found and how populations change. He further explores the relationships of reptiles with their abiotic and...
Desert Tortoise Ecology, Health, Habitat, and Conservation Biology
The desert tortoise is listed as “threatened” under the Endangered Species Act. USGS WERC scientists, along with project partners have been conducting long-term analyses on how changes in the southwestern deserts of the United States can affect desert tortoise populations. Dr. Todd Esque and his team are investigating how habitat disturbances and restoration projects influence tortoise populations...
Reptile Biodiversity in the Pacific Basin Islands
Dr. Robert Fisher and his colleagues have teamed up with the U.S. Fish and Wildlife, The Nature Conservancy and multiple universities to conduct several types of studies that will address high priority issues related to reptiles in the Pacific Basin Islands. These studies will provide new information about species diversity, endemicity, biology and demography of reptile fauna and will lay the...
Relocating and Augmenting Desert Tortoise Populations
As resource managers balance the needs of humans and wildlife, WERC’s Dr. Berry provides the necessary science to inform decisions on shared lands. Visit the “Science” tab to delve into specific projects.
Human Influence on Desert Tortoise Habitats
The deserts of the Southwest are under increasing pressure from growing human communities. The spread of cities, agricultural fields, grazing livestock, power plants, and other forms of human development in the past and present have affected the region’s natural resources, including its wildlife. WERC’s Dr. Kristin Berry is studying the response of threatened desert tortoises to changing habitats...
Ecology and Biology of Desert Tortoises
WERC wildlife biologist Dr. Kristin Berry has more than forty years of experience studying Agassiz’s desert tortoise. As the lead on several USGS projects, Dr. Berry continues to lend her expertise to investigating the status, genetics, and behavior of Agassiz’s tortoise populations in the Mojave Desert.
Turtle Ecology
Turtles are among the most recognizable and iconic of animals. Any animal with a shell and a backbone is a turtle whether they are called turtles, tortoises, or terrapins. In fact, terrapin is an Algonquian Native American name for turtle. Worldwide there are 356 turtle species on all continents except for Antarctica. The United States has more species than any other country with about 62...
Giant Constrictor Snakes in Florida: A Sizeable Research Challenge
Since the mid-1990s, several species of non-native, giant constrictor snakes, such as Burmese pythons and boa constrictors, have surfaced in localities throughout southern Florida. Several are known or suspected to be breeding and appear to be spreading northward. Increasingly, media and other reports of sightings or encounters with these animals have emphasized the dangers they could impose on...
Population Biology and Ecology of Diamondback Terrapins in Mangrove Forested Ecosystems in the Greater Everglades
Long-term capture-recapture research in the Everglades National Park provides baseline information on the Diamondback Terrapin, a species that may be threatened by human disturbances.
Explore our science using the data below.
Recent publications (2020-2022) related to USGS reptile research are listed below. A complete listing of USGS reptile publications is available from the button below.
Filter Total Items: 23
Tropicalization of temperate ecosystems in North America: The northward range expansion of tropical organisms in response to warming winter temperatures
Tropicalization is a term used to describe the transformation of temperate ecosystems by poleward‐moving tropical organisms in response to warming temperatures. In North America, decreases in the frequency and intensity of extreme winter cold events are expected to allow the poleward range expansion of many cold‐sensitive tropical organisms, sometimes at the expense of temperate organisms. Althoug
Authors
Michael Osland, Philip Stevens, Margaret Lamont, Richard Brusca, Kristen Hart, Hardin Waddle, Catherine Langtimm, Caroline Williams, Barry Keim, Adam Terando, Eric Reyier, Katie Marshall, Michael E. Loik, Ross Boucek, Amanda Lewis, Jeffrey A. Seminoff
Environmental contamination and unusual snake mortality in an urban national wildlife refuge
The National Wildlife Refuge (NWR) System protects ~150 million acres of land and water in the United States and provides habitat for >2,000 native vertebrates species. Although legally protected, wildlife populations within these refuges can be threatened by anthropogenic activities. The lack of knowledge about such threats has the potential to undermine biodiversity conservation.
We investigate
Authors
Kimberly A. Terrell, Anne Ballmann, Ashli Brown, Christina Childers, Susan Knowles, Ashley Meredith, Darrell Sparks
Biological and habitat assessment of the Lower Rouge River, Michigan 2018
A key component of evaluating the success of habitat remediation projects is determining preremediation conditions, biotic and abiotic, to establish a baseline and compare with postproject conditions. The Rouge River, Michigan, is a Great Lakes Area of Concern with a listed Beneficial Use Impairment related to loss of fish and wildlife habitat. A biological and habitat assessment was completed in
Authors
Edward F. Roseman, Jason Fischer, Robin L. DeBruyne, Scott A. Jackson
Movement-assisted localization from acoustic telemetry data
Acoustic telemetry technologies are being increasingly deployed to study a variety of aquatic taxa including fishes, reptiles, and marine mammals. Large cooperative telemetry networks produce vast quantities of data useful in the study of movement, resource selection and species distribution. Efficient use of acoustic telemetry data requires estimation of acoustic source locations from detections
Authors
Nathan J. Hostetter, Andy Royle
Landscape dominance of introduced herpetofauna on an oceanic island
Habitat loss and fragmentation can negatively impact native wildlife and facilitate establishment
of introduced species. On islands, introduced species are a primary cause of
extinction and can alter community membership through predation or competition for
resources. Consequently, elucidating the distribution of introduced and native species can
improve understanding of the potential synergistic
Authors
Eric Thomas Hileman, Bradley A. Eichelberger, Jill Liske-Clark, Patrick D Barnhart, Robert Reed, Amy A. Yackel Adams, Melia G. Nafus
Herpetofauna occupancy and community composition along a tidal swamp salinity gradient
Occupancy patterns of herpetofauna in most tidal freshwater swamps are unknown. Tidal freshwater swamps currently face multiple threats, including salinization, which can influence their associated plant and animal communities. The impacts of salinization to herpetofauna communities in tidal freshwater swamps have not been assessed. To improve predictions regarding these herpetofauna, we conducted
Authors
Sidney T Godfrey, J. Hardin Waddle, Robert F Baldwin, William H. Conner, William C Bridges, Jamie A. Duberstein
Introgression obscures lineage boundaries and phylogeographic history in the western banded gecko, Coleonyx variegatus (Squamata: Eublepharidae)
The geomorphological formation of the Baja California peninsula and the Gulf of California is a principal driver of diversification for the reptiles of North America’s warm deserts. The western banded gecko, Coleonyx variegatus, is distributed throughout the Mojave, Sonoran and Peninsular deserts. In this study we use multilocus sequence data to address deep phylogeographic structure within C. var
Authors
Dean H Leavitt, Bradford Hollingsworth, Robert N. Fisher, Tod W Reeder
Shifts in hatching date of American crocodile (Crocodylus acutus) in southern Florida
Globally temperature of marine environments is on the rise and temperature plays an important role in the life-history of reptiles. In this study, we examined the relationship between sea surface temperature and average date of hatching for American crocodiles (Crocodylus acutus) over a 37-year period at two nesting sites, Everglades National Park and Florida Power and Light Turkey Point Power Pla
Authors
Michael Cherkiss, James I. Watling, Laura A. Brandt, Frank J. Mazzotti, Jim Linsay, Jeffrey S. Beauchamp, Jerome J. Lorenz, Joseph Wasilewski, Ikuko Fujisaki, Kristen Hart
Use of visual surveys and radiotelemetry reveals sources of detection bias for a cryptic snake at low densities
Transect surveys are frequently used to estimate distribution and abundance of species across a landscape, yet a proportion of individuals present will be missed because either they were out of view and unavailable for detection or they were available but not detected because the surveyors missed them. These situations lead to availability and perception bias, respectively, and can result in misle
Authors
SM Boback, Melia G. Nafus, Amy A. Yackel Adams, Robert Reed
Reptiles under the conservation umbrella of the greater sage‐grouse
In conservation paradigms, management actions for umbrella species also benefit co‐occurring species because of overlapping ranges and similar habitat associations. The greater sage‐grouse (Centrocercus urophasianus) is an umbrella species because it occurs across vast sagebrush ecosystems of western North America and is the recipient of extensive habitat conservation and restoration efforts that
Authors
David Pilliod, Michelle Jeffries, Robert Arkle, Deanna H. Olson
Pilot inventory of mammals, reptiles, and amphibians, Golden Gate National Recreation Area, California, 1990-1997
The United States Geological Survey Golden Gate Field Station conducted a baseline inventory of terrestrial vertebrates within the Golden Gate National Recreation Area (GGNRA), Marin, San Francisco, and San Mateo Counties, California between 1990 and 1997. We established 456 permanent study plots in 6 major park habitats, including grassland, coastal scrub, riparian woodland, coastal wetland, broa
Authors
Marcia Semenoff-Irving, Judd A. Howell