Michael Cherkiss' research interests include population ecology and conservation of amphibians and reptiles, with experience extending to radio telemetry and transmitter attachment on pythons, crocodilians, sea turtles and other species.
BACKGROUND
Prior to joining the USGS, Cherkiss was a biologist with the University of Florida for over ten years. He has over 15 years’ experience conducting research in the coastal areas of South Florida, Everglades ecosystems and internationally throughout the Caribbean, Central and South American.
Education and Certifications
M.S., Wildlife Ecology and Conservation, University of Florida, 2000
B.S., Wildlife Ecology and Conservation, University of Florida, 1996
Science and Products
Developing Future Habitat Condition Scenarios for Wildlife in the Imperiled Pine Rockland Ecosystem of South Florida
The pine rockland ecosystem is found only in south Florida and the Bahamas and provides important habitat for numerous rare and endemic plants and animals. These include 18 species that are already federally listed as threatened or endangered and four other species petitioned for listing that are scheduled for development of Species Status Assessments (SSAs). Today, south Florida’s pine rockland e...
Evaluation of Tegu Movements and Habitat Use in Relation to Location and Habitat
Tegus are breeding, they have a diverse diet, and they are established in areas throughout South Florida. USGS is tracking this problematic reptile species to better understand their movements and habitat use to help managers prevent dispersal into new areas.
Spatial Ecology of the American Crocodile (Crocodylus acutus) and American Alligator (Alligator mississippiensis) in the Greater Everglades
Satellite/GPS tags help USGS researchers understand the movements of American Alligators and American Crocodiles in the Greater Everglades.
Tracking durations for marine turtles satellite tagged in Gulf of Mexico and Caribbean sites, 2008-2019
This dataset contains tracking durations for several species of sea turtles tagged with satellite tags between 2008 and 2019. It contains information on species, turtle size, capture methods, tag type, how many days each tag transmitted, whether or not the tag was still attached upon recapture, fouling 'status' of the tag, and foraging region. This dataset thus allows estimation of tracking durati
Burmese python acceleration and location data, Everglades National Park, 2010 - 2012
The dataset contains 3 components: (1) acceleration data logger (ADL) data, (2) GPS location data, and (3) body temperature data. We have ADL data from pythons in captivity (N = 2) and in free-ranging snakes (N=4). We have GPS data for 3 out of 4 free-ranging snakes. We have body temperature data for all 4 free-ranging snakes.
Hatch dates of American crocodile nests in Everglades National Park and Turkey Point Power Plant 1983-2016
We monitored nests from 1983 to 2016 during the crocodile nesting season (April through August) as part of a long-term American crocodile monitoring programs within Everglades National Park (ENP; since 1978) and Turkey Point Power Plant (TP; since 1983). Nests were located during April and May (egg laying period) and monitored from June to August (hatching period). During the hatching period, surv
Filter Total Items: 40
Stable isotopes used to infer trophic position of green turtles (Chelonia mydas) from Dry Tortugas National Park, Gulf of Mexico, United States
Evaluating resource use patterns for imperiled species is critical for understanding what supports their populations. Here we established stable isotope (δ13C, δ15N) values for the endangered green sea turtle (Chelonia mydas) population found within the boundaries of Dry Tortugas National Park (DRTO), south Florida, USA. There is little gene flow between turtles sampled at DRTO and in other rooker
Space use and relative habitat selection for immature green turtles within a Caribbean marine protected area
Background
A better understanding of sea turtle spatial ecology is critical for the continued conservation of imperiled sea turtles and their habitats. For resource managers to develop the most effective conservation strategies, it is especially important to examine how turtles use and select for habitats within their developmental foraging grounds. Here, we examine the space use and relative habi
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
Acoustic tag retention rate varies between juvenile green and hawksbill sea turtles
Background
Biotelemetry has become a key tool for studying marine animals in the last decade, and a wide range of electronic tags are now available for answering a range of research questions. However, comparatively, less attention has been given to attachment methods for these tags and the implications of tag retention on study design, especially when designing a comparative study looking at mult
Influence of salinity on relative density of American crocodiles (Crocodylus acutus) in Everglades National Park: Implications for restoration of Everglades ecosystems
The status of the American crocodile (Crocodylus acutus) has long been a matter of concern in Everglades National Park (ENP) due to its classification as a federal and state listed species, its recognition as a flagship species, and its function as an ecosystem indicator. Survival and recovery of American crocodiles has been linked with regional hydrological conditions, especially freshwater flow
Satellite tracking of hawksbill turtles nesting at Buck Island Reef National Monument, US Virgin Islands: Inter-nesting and foraging period movements and migrations
To conserve imperiled marine species, an understanding of high-density use zones is necessary prior to designing and evaluating management strategies that improve their survival. We satellite-tracked turtles captured after nesting at Buck Island ReefNational Monument (BIRNM), St. Croix, US Virgin Islands to determine habitat-use patterns of endangered adult female hawksbills (Eretmochelys imbricat
Everglades Invasive Reptile and Amphibian Monitoring Program
The Everglades Invasive Reptile and Amphibian Monitoring Program (EIRAMP) provides a scientific framework for integrated EDRR, outreach, and monitoring for invasive wildlife in South Florida. EIRAMP also monitors native reptiles, amphibians and mammals to assess impacts of invasive species.
South Florida has more nonnative species of reptiles and amphibians than anywhere else in the world. Some o
Variation in home range size and patterns in adult female American crocodiles Crocodylus acutus
The American crocodile Crocodylus acutus is a threatened species that uses relatively deep, open-water habitats with low salinity. Adult female American crocodiles nest on sandy coastal beaches, islands or human-made berms, assist in the hatching process, and can travel long distances to nesting habitat. We satellite-tracked 15 adult female American crocodiles in 2 hydrologically distinct areas in
Life histories and conservation of long-lived reptiles, an illustration with the American crocodile (Crocodylus acutus)
Successful species conservation is dependent on adequate estimates of population dynamics, but age-specific demographics are generally lacking for many long-lived iteroparous species such as large reptiles. Accurate demographic information allows estimation of population growth rate, as well as projection of future population sizes and quantitative analyses of fitness trade-offs involved in the ev
Ecological regime shift drives declining growth rates of sea turtles throughout the West Atlantic
Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorou
Conservation genetics of American crocodile, Crocodylus acutus, populations in Pacific Costa Rica
Maintaining genetic diversity is crucial for the survival and management of threatened and endangered species. In this study, we analyzed genetic diversity and population genetic structure at neutral loci in American crocodiles, Crocodylus acutus, from several areas (Parque Nacional Marino Las Baulas, Parque Nacional Santa Rosa, Parque Nacional Palo Verde, Rio Tarcoles, and Osa Conservation Area)
Resident areas and migrations of female green turtles nesting at Buck Island Reef National Monument, St. Croix, U.S. Virgin Islands
Satellite tracking in marine turtle studies can reveal much about their spatial use of breeding areas, migration zones, and foraging sites. We assessed spatial habitat-use patterns of 10 adult female green turtles (Chelonia mydas) nesting at Buck Island Reef National Monument, U.S. Virgin Islands (BIRNM) from 2011 – 2014. Turtles ranged in size from 89.0 – 115.9 cm CCL (mean + SD = 106.8 + 7.7 cm
Science and Products
- Science
Developing Future Habitat Condition Scenarios for Wildlife in the Imperiled Pine Rockland Ecosystem of South Florida
The pine rockland ecosystem is found only in south Florida and the Bahamas and provides important habitat for numerous rare and endemic plants and animals. These include 18 species that are already federally listed as threatened or endangered and four other species petitioned for listing that are scheduled for development of Species Status Assessments (SSAs). Today, south Florida’s pine rockland e...Evaluation of Tegu Movements and Habitat Use in Relation to Location and Habitat
Tegus are breeding, they have a diverse diet, and they are established in areas throughout South Florida. USGS is tracking this problematic reptile species to better understand their movements and habitat use to help managers prevent dispersal into new areas.Spatial Ecology of the American Crocodile (Crocodylus acutus) and American Alligator (Alligator mississippiensis) in the Greater Everglades
Satellite/GPS tags help USGS researchers understand the movements of American Alligators and American Crocodiles in the Greater Everglades. - Data
Tracking durations for marine turtles satellite tagged in Gulf of Mexico and Caribbean sites, 2008-2019
This dataset contains tracking durations for several species of sea turtles tagged with satellite tags between 2008 and 2019. It contains information on species, turtle size, capture methods, tag type, how many days each tag transmitted, whether or not the tag was still attached upon recapture, fouling 'status' of the tag, and foraging region. This dataset thus allows estimation of tracking duratiBurmese python acceleration and location data, Everglades National Park, 2010 - 2012
The dataset contains 3 components: (1) acceleration data logger (ADL) data, (2) GPS location data, and (3) body temperature data. We have ADL data from pythons in captivity (N = 2) and in free-ranging snakes (N=4). We have GPS data for 3 out of 4 free-ranging snakes. We have body temperature data for all 4 free-ranging snakes.Hatch dates of American crocodile nests in Everglades National Park and Turkey Point Power Plant 1983-2016
We monitored nests from 1983 to 2016 during the crocodile nesting season (April through August) as part of a long-term American crocodile monitoring programs within Everglades National Park (ENP; since 1978) and Turkey Point Power Plant (TP; since 1983). Nests were located during April and May (egg laying period) and monitored from June to August (hatching period). During the hatching period, surv - Publications
Filter Total Items: 40
Stable isotopes used to infer trophic position of green turtles (Chelonia mydas) from Dry Tortugas National Park, Gulf of Mexico, United States
Evaluating resource use patterns for imperiled species is critical for understanding what supports their populations. Here we established stable isotope (δ13C, δ15N) values for the endangered green sea turtle (Chelonia mydas) population found within the boundaries of Dry Tortugas National Park (DRTO), south Florida, USA. There is little gene flow between turtles sampled at DRTO and in other rookerSpace use and relative habitat selection for immature green turtles within a Caribbean marine protected area
Background A better understanding of sea turtle spatial ecology is critical for the continued conservation of imperiled sea turtles and their habitats. For resource managers to develop the most effective conservation strategies, it is especially important to examine how turtles use and select for habitats within their developmental foraging grounds. Here, we examine the space use and relative habiShifts 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 PlaAcoustic tag retention rate varies between juvenile green and hawksbill sea turtles
Background Biotelemetry has become a key tool for studying marine animals in the last decade, and a wide range of electronic tags are now available for answering a range of research questions. However, comparatively, less attention has been given to attachment methods for these tags and the implications of tag retention on study design, especially when designing a comparative study looking at multInfluence of salinity on relative density of American crocodiles (Crocodylus acutus) in Everglades National Park: Implications for restoration of Everglades ecosystems
The status of the American crocodile (Crocodylus acutus) has long been a matter of concern in Everglades National Park (ENP) due to its classification as a federal and state listed species, its recognition as a flagship species, and its function as an ecosystem indicator. Survival and recovery of American crocodiles has been linked with regional hydrological conditions, especially freshwater flowSatellite tracking of hawksbill turtles nesting at Buck Island Reef National Monument, US Virgin Islands: Inter-nesting and foraging period movements and migrations
To conserve imperiled marine species, an understanding of high-density use zones is necessary prior to designing and evaluating management strategies that improve their survival. We satellite-tracked turtles captured after nesting at Buck Island ReefNational Monument (BIRNM), St. Croix, US Virgin Islands to determine habitat-use patterns of endangered adult female hawksbills (Eretmochelys imbricatEverglades Invasive Reptile and Amphibian Monitoring Program
The Everglades Invasive Reptile and Amphibian Monitoring Program (EIRAMP) provides a scientific framework for integrated EDRR, outreach, and monitoring for invasive wildlife in South Florida. EIRAMP also monitors native reptiles, amphibians and mammals to assess impacts of invasive species. South Florida has more nonnative species of reptiles and amphibians than anywhere else in the world. Some oVariation in home range size and patterns in adult female American crocodiles Crocodylus acutus
The American crocodile Crocodylus acutus is a threatened species that uses relatively deep, open-water habitats with low salinity. Adult female American crocodiles nest on sandy coastal beaches, islands or human-made berms, assist in the hatching process, and can travel long distances to nesting habitat. We satellite-tracked 15 adult female American crocodiles in 2 hydrologically distinct areas inLife histories and conservation of long-lived reptiles, an illustration with the American crocodile (Crocodylus acutus)
Successful species conservation is dependent on adequate estimates of population dynamics, but age-specific demographics are generally lacking for many long-lived iteroparous species such as large reptiles. Accurate demographic information allows estimation of population growth rate, as well as projection of future population sizes and quantitative analyses of fitness trade-offs involved in the evEcological regime shift drives declining growth rates of sea turtles throughout the West Atlantic
Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorouConservation genetics of American crocodile, Crocodylus acutus, populations in Pacific Costa Rica
Maintaining genetic diversity is crucial for the survival and management of threatened and endangered species. In this study, we analyzed genetic diversity and population genetic structure at neutral loci in American crocodiles, Crocodylus acutus, from several areas (Parque Nacional Marino Las Baulas, Parque Nacional Santa Rosa, Parque Nacional Palo Verde, Rio Tarcoles, and Osa Conservation Area)Resident areas and migrations of female green turtles nesting at Buck Island Reef National Monument, St. Croix, U.S. Virgin Islands
Satellite tracking in marine turtle studies can reveal much about their spatial use of breeding areas, migration zones, and foraging sites. We assessed spatial habitat-use patterns of 10 adult female green turtles (Chelonia mydas) nesting at Buck Island Reef National Monument, U.S. Virgin Islands (BIRNM) from 2011 – 2014. Turtles ranged in size from 89.0 – 115.9 cm CCL (mean + SD = 106.8 + 7.7 cm - News