Turtle Ecology Active
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 currently recognized. Mexico is in second place with 49 species, making North America a global hotspot for turtle biodiversity, especially in the southeastern United States. Unfortunately, turtles are now the most imperiled major group of vertebrates (animals with backbones) with about 60% of modern turtles already extinct or threatened. Reasons for their declining status include habitat destruction and overexploitation for the pet trade and as food. Turtles play important ecological roles in their environments that are diminished as their populations decline. I have been studying turtles worldwide for over 35 years and that research continues. Due to the longevity of many turtle species, long-term studies are necessary to document changes in populations
Background & Importance
Resource managers are concerned about the declining status of many of the world’s turtle species, especially those that are listed as threatened or endangered under the Endangered Species Act. In addition, many species are data deficient: we simply don’t know enough about their biology or abundance to effectively manage turtle populations. Research conducted by U.S. Geological Survey scientists provides resource managers with information that allows them to make knowledgeable decisions that affect conservation and management of turtles.
General Methods
Field techniques vary according to the objectives of each project. Generally, turtles are captured in the field, and marked with unique and permanent notches on their shell that allow researchers to identify individuals at subsequent captures to measure growth, movements, etc. Individual turtles are measured, weighed and sex is determined by examining shell shape and tail size. In some studies, a small sample of turtles are outfitted with radio transmitters that allow scientists to find them on subsequent visits to the field site. In other studies, adult females are X-rayed to determine clutch size, clutch frequency and egg width to determine reproductive potential. Previous published research by the Principal Investigator determined that this technique poses minimal risk to females and embryos. Small blood samples are occasionally taken to obtain DNA used to compare genetic differences between populations. Detailed measurements and DNA samples are used to determine the taxonomic status of poorly-studied species. To date the Principal Investigator has discovered and described four new species of turtles: one in southern Japan (Ryukyu yellow-margined box turtle) and three in the United States (Escambia map turtle, Pascagoula map turtle, Pearl River map turtle).
Important Results
This research summary does not include projects on desert tortoises or western pond turtles. Those species are covered on separate web pages. The Principal Investigator started turtle research in the eastern United States in 1980. Highlights of the research program are given under regional subheadings below:
Pennsylvania – Dr. Carl Ernst, formerly of George Mason University, started research on the ecology of a community of six species of turtles in Lancaster County, Pennsylvania in 1965. Collaboration with Dr. Ernst lead to the publication of several papers on the growth of wood turtles and bog turtles and a long-term study of overwintering behavior in hatchling turtles. The latter study demonstrated that some turtle species hibernate in their nest after emerging from the egg while others emerge the same year as the nest was constructed. Some species do both depending on seasonal precipitation.
Alabama – The Principal Investigator has long been interested in the diversity of map turtles in the southeastern United States. Fourteen species are currently recognized from the Apalachicola River of Florida to the Guadalupe River of Texas. Early research resulted in the description of two new species in the Escambia and Pascagoula Rivers of Alabama and Mississippi. In 2009 another species was described from the Pearl River of Mississippi and Louisiana. More recently, a hybrid swarm of Barbour’s map turtles and Escambia Map turtles was identified using DNA analysis in the Choctawhatchee and Pea Rivers of Alabama and Florida.
Arizona – USGS scientists are working with Montezuma Castle National Monument to study the Sonora mud turtle population at Montezuma Well, a large natural spring in central Arizona. Sonora mud turtles are found in Arizona, New Mexico and Mexico. They disappeared from California in the 1960s likely from habitat modification due to the effects of river regulation from dams. Montezuma Well was a popular site for releasing unwanted pet red-eared slider turtles. USGS scientists removed all the non-native turtle species as part of an experiment to see if the population of Sonora mud turtles would benefit by removing competitor species. That research is ongoing and has resulted in several publications. It is one of only a few examples where invasive species were completely removed from inside an area administered by the National Park Service.
South Carolina – A great deal of research has been concentrated on the yellow-bellied slider turtle, a common species throughout the southeastern United States. Additional research is focused on the diamond-backed terrapin, the only turtle in the world that spends its entire life in brackish tidal marshes at the interface of freshwater and marine environments. Diamond-backed terrapins are found in the United States, from Cape Cod, Massachusetts, to Corpus Christi, Texas, with an isolated population in Bermuda. The Principal Investigator is a key partner in the longest running study in the world, now in its 35th year at Kiawah Island, South Carolina. Terrapins have decreased throughout their range, and a major cause of the decline is drowning in commercial and recreational crab traps. Terrapins were once the most economically important reptile in the world due to their popularity as gourmet food in the late 1800s and early 1900s. Modern threats to their continued survival also include habitat modification and destruction.
New Mexico – In collaboration with the New Mexico Department of Game and Fish, the Principal Investigator is monitoring the reproductive biology of turtles in the Rio Grande and the Pecos rivers since 2012. That research is providing basic information on poorly-studied species, especially the Rio Grande cooter.
Morocco – In 2008, the Principal Investigator received a Fulbright scholarship to conduct research in Morocco. During that time he trained faculty and students at Cady Ayaad University in Marrakech in basic techniques for turtle research resulting in publications and ongoing collaboration. Students subsequently received advanced degrees as a result of their research.
Japan – In 2014, the Principal Investigator was invited to be the Keynote speaker at the second Japanese Freshwater Turtle Symposium in Kobe, Japan. The invitation was a result of his expertise with the biology of slider turtles that are an invasive species in Japan and a perceived threat to the survival of several native Japanese turtles. Collaboration is ongoing and publications are resulting. After the visit to Japan, his collaborators came to the United States to film a movie that included the Principal Investigator and his research on turtles in Arizona and California that later aired in Japan. The Principal Investigator has a long history of research on Asian turtles.
Galápagos – Because of the Principal Investigator’s expertise with turtles and tortoises, in 2012, he was invited by the Galápagos Conservancy to attend a workshop in the Galápagos to develop a ten year strategy for restoration and repatriation of Galápagos tortoises to all islands in the archipelago.
Below are other science projects related to this project.
The Gemini Solar Project
Desert Tortoise Ecology and Renewable Energy Development
Desert Tortoise Ecology
Below are selected publications associated with this project.
Injuries and abnormalities of the southwestern pond turtle (Actinemys pallida) in the Mojave River of California
The southwestern pond turtle (Actinemys pallida) is a semiaquatic turtle that occasionally spends time on land to bask, oviposit, make intermittent overland movements, and overwinter in terrestrial locations. Use of both aquatic and terrestrial environments exposes semiaquatic turtles to increased risk of injury or mortality from floods, predation attempts, and other environmental hazards (e.g., h
Re-evaluating invasive species in degraded ecosystems: A case study of red-eared slider turtles as partial ecological analogs
Growing as slow as a turtle: Unexpected maturational differences in a small, long-lived species
Western pond turtles in the Mojave Desert? A review of their past, present, and possible future
Non-native Pond Sliders cause long-term decline of native Sonora Mud Turtles: A 33-year before-after study in an undisturbed natural environment
A watershed moment: Analysis of sub-basins refocuses the geography of turtle conservation across the globe
Turtles and tortoises are in trouble
Turtle biogeography: Global regionalization and conservation priorities
Understanding reproductive allometry in turtles: A slippery “slope”
An introduced breeding population of Chrysemys picta marginata in the Kaibab National Forest, northern Arizona
Where has turtle ecology been, and where is it going?
Where have all the turtles gone, and why does it matter?
Below are news features about turtle and tortoise research led by the Southwest Biological Science Center.
Below are partners associated with this project.
- Overview
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 currently recognized. Mexico is in second place with 49 species, making North America a global hotspot for turtle biodiversity, especially in the southeastern United States. Unfortunately, turtles are now the most imperiled major group of vertebrates (animals with backbones) with about 60% of modern turtles already extinct or threatened. Reasons for their declining status include habitat destruction and overexploitation for the pet trade and as food. Turtles play important ecological roles in their environments that are diminished as their populations decline. I have been studying turtles worldwide for over 35 years and that research continues. Due to the longevity of many turtle species, long-term studies are necessary to document changes in populations
Background & Importance
Resource managers are concerned about the declining status of many of the world’s turtle species, especially those that are listed as threatened or endangered under the Endangered Species Act. In addition, many species are data deficient: we simply don’t know enough about their biology or abundance to effectively manage turtle populations. Research conducted by U.S. Geological Survey scientists provides resource managers with information that allows them to make knowledgeable decisions that affect conservation and management of turtles.
General Methods
Field techniques vary according to the objectives of each project. Generally, turtles are captured in the field, and marked with unique and permanent notches on their shell that allow researchers to identify individuals at subsequent captures to measure growth, movements, etc. Individual turtles are measured, weighed and sex is determined by examining shell shape and tail size. In some studies, a small sample of turtles are outfitted with radio transmitters that allow scientists to find them on subsequent visits to the field site. In other studies, adult females are X-rayed to determine clutch size, clutch frequency and egg width to determine reproductive potential. Previous published research by the Principal Investigator determined that this technique poses minimal risk to females and embryos. Small blood samples are occasionally taken to obtain DNA used to compare genetic differences between populations. Detailed measurements and DNA samples are used to determine the taxonomic status of poorly-studied species. To date the Principal Investigator has discovered and described four new species of turtles: one in southern Japan (Ryukyu yellow-margined box turtle) and three in the United States (Escambia map turtle, Pascagoula map turtle, Pearl River map turtle).
Important Results
This research summary does not include projects on desert tortoises or western pond turtles. Those species are covered on separate web pages. The Principal Investigator started turtle research in the eastern United States in 1980. Highlights of the research program are given under regional subheadings below:
Pennsylvania – Dr. Carl Ernst, formerly of George Mason University, started research on the ecology of a community of six species of turtles in Lancaster County, Pennsylvania in 1965. Collaboration with Dr. Ernst lead to the publication of several papers on the growth of wood turtles and bog turtles and a long-term study of overwintering behavior in hatchling turtles. The latter study demonstrated that some turtle species hibernate in their nest after emerging from the egg while others emerge the same year as the nest was constructed. Some species do both depending on seasonal precipitation.
Alabama – The Principal Investigator has long been interested in the diversity of map turtles in the southeastern United States. Fourteen species are currently recognized from the Apalachicola River of Florida to the Guadalupe River of Texas. Early research resulted in the description of two new species in the Escambia and Pascagoula Rivers of Alabama and Mississippi. In 2009 another species was described from the Pearl River of Mississippi and Louisiana. More recently, a hybrid swarm of Barbour’s map turtles and Escambia Map turtles was identified using DNA analysis in the Choctawhatchee and Pea Rivers of Alabama and Florida.
Arizona – USGS scientists are working with Montezuma Castle National Monument to study the Sonora mud turtle population at Montezuma Well, a large natural spring in central Arizona. Sonora mud turtles are found in Arizona, New Mexico and Mexico. They disappeared from California in the 1960s likely from habitat modification due to the effects of river regulation from dams. Montezuma Well was a popular site for releasing unwanted pet red-eared slider turtles. USGS scientists removed all the non-native turtle species as part of an experiment to see if the population of Sonora mud turtles would benefit by removing competitor species. That research is ongoing and has resulted in several publications. It is one of only a few examples where invasive species were completely removed from inside an area administered by the National Park Service.
South Carolina – A great deal of research has been concentrated on the yellow-bellied slider turtle, a common species throughout the southeastern United States. Additional research is focused on the diamond-backed terrapin, the only turtle in the world that spends its entire life in brackish tidal marshes at the interface of freshwater and marine environments. Diamond-backed terrapins are found in the United States, from Cape Cod, Massachusetts, to Corpus Christi, Texas, with an isolated population in Bermuda. The Principal Investigator is a key partner in the longest running study in the world, now in its 35th year at Kiawah Island, South Carolina. Terrapins have decreased throughout their range, and a major cause of the decline is drowning in commercial and recreational crab traps. Terrapins were once the most economically important reptile in the world due to their popularity as gourmet food in the late 1800s and early 1900s. Modern threats to their continued survival also include habitat modification and destruction.
New Mexico – In collaboration with the New Mexico Department of Game and Fish, the Principal Investigator is monitoring the reproductive biology of turtles in the Rio Grande and the Pecos rivers since 2012. That research is providing basic information on poorly-studied species, especially the Rio Grande cooter.
Morocco – In 2008, the Principal Investigator received a Fulbright scholarship to conduct research in Morocco. During that time he trained faculty and students at Cady Ayaad University in Marrakech in basic techniques for turtle research resulting in publications and ongoing collaboration. Students subsequently received advanced degrees as a result of their research.
Japan – In 2014, the Principal Investigator was invited to be the Keynote speaker at the second Japanese Freshwater Turtle Symposium in Kobe, Japan. The invitation was a result of his expertise with the biology of slider turtles that are an invasive species in Japan and a perceived threat to the survival of several native Japanese turtles. Collaboration is ongoing and publications are resulting. After the visit to Japan, his collaborators came to the United States to film a movie that included the Principal Investigator and his research on turtles in Arizona and California that later aired in Japan. The Principal Investigator has a long history of research on Asian turtles.
Galápagos – Because of the Principal Investigator’s expertise with turtles and tortoises, in 2012, he was invited by the Galápagos Conservancy to attend a workshop in the Galápagos to develop a ten year strategy for restoration and repatriation of Galápagos tortoises to all islands in the archipelago.
- Science
Below are other science projects related to this project.
The Gemini Solar Project
The United States is developing renewable energy resources, especially solar, at a rapid rate. Although renewable energy development is widely perceived by the public as “green technology,” construction, operation, maintenance, and eventual decommissioning of facilities all have known and potential negative impacts to natural resources, including plant communities and wildlife. This is especially...Desert Tortoise Ecology and Renewable Energy Development
The desert Southwest is experiencing rapid development of utility-scale solar and wind energy facilities. Although clean renewable energy has environmental benefits, it can also have negative impacts on wildlife and their habitats. Understanding those impacts and effectively mitigating them is a major goal of industry and resource managers. One species of particular concern is Agassiz’s desert...Desert Tortoise Ecology
Agassiz’s desert tortoises ( Gopherus agassizii ) approach the southern edge of their mostly Mojave Desert range near Joshua Tree National Park. Modern desert tortoise research started in the Park in 1978 when the first tortoise population census was conducted on a one square mile area in the Pinto Basin known as the “Barrow Plot.” U.S. Geological Survey research began at the plot in 1997 and... - Publications
Below are selected publications associated with this project.
Filter Total Items: 42Injuries and abnormalities of the southwestern pond turtle (Actinemys pallida) in the Mojave River of California
The southwestern pond turtle (Actinemys pallida) is a semiaquatic turtle that occasionally spends time on land to bask, oviposit, make intermittent overland movements, and overwinter in terrestrial locations. Use of both aquatic and terrestrial environments exposes semiaquatic turtles to increased risk of injury or mortality from floods, predation attempts, and other environmental hazards (e.g., h
AuthorsKristy L. Cummings, Jeffrey E. Lovich, Michele (Shellie) R. Puffer, Sarah Greely, Christopher D Otahal, James GannonRe-evaluating invasive species in degraded ecosystems: A case study of red-eared slider turtles as partial ecological analogs
Exotic species are often vilified as "bad" without consideration of the potential they have for contributing to ecological functions in degraded ecosystems. The red-eared slider turtle (RES) has been disparaged as one of the worst invasive species. Based on this review, we suggest that RES contribute some ecosystem functions in urban wetlands comparable to those provided by the native turtles theyAuthorsMarc Dupuis-Desormeaux, Jeffrey E. Lovich, J. Whitfield GibbonsGrowing as slow as a turtle: Unexpected maturational differences in a small, long-lived species
Turtle body size is associated with demographic and other traits like mating success, reproductive output, maturity, and survival. As such, growth analyses are valuable for testing life history theory, demographic modeling, and conservation planning. Two important but unsettled research areas relate to growth after maturity and growth rate variation. If individuals exhibit indeterminate growth aftAuthorsDevin Edmonds, Michael J. Dreslik, Jeffrey E. Lovich, Thomas P. Wilson, Carl H. ErnstWestern pond turtles in the Mojave Desert? A review of their past, present, and possible future
=The western pond turtle (WPT) was formerly considered a single species (Actinemys or Emys marmorata) that ranged from southern British Columbia, Canada to Baja California, México. More recently it was divided into a northern and a southern species. WPTs are found primarily in streams that drain into the Pacific Ocean, although scattered populations exist in endorheic drainages of the Great BasinAuthorsJeffrey E. Lovich, George T. Jefferson, Robert E. Reynolds, Peter A. Scott, H. Bradley Shaffer, Shellie R. Puffer, Sarah Greely, Kristy L. Cummings, Robert N. Fisher, Kathie Meyer-Wilkins, Doug Gomez, Morgan Ford, Christopher D OtahalNon-native Pond Sliders cause long-term decline of native Sonora Mud Turtles: A 33-year before-after study in an undisturbed natural environment
Using a before-after study design in a stable, largely undisturbed pond habitat and a dataset spanning 33 years, we document and describe the decline of native Sonora mud turtles (Kinosternon sonoriense) after the introduction of non-native pond sliders (Trachemys scripta). The Sonora mud turtle population in Montezuma Well in central Arizona, USA, declined to less than 25% of previous numbers, frAuthorsCharles A. Drost, Jeffrey E. Lovich, Philip C. Rosen, Matthew Malone, Steven D. GarberA watershed moment: Analysis of sub-basins refocuses the geography of turtle conservation across the globe
Conservation planners use a variety of decision-making tools, many of which require identifying and prioritizing spatial units based on their biodiversity and levels of imperilment. Turtles are highly imperiled, but present schemes for determining global priority areas are focused mostly on broad regional scales. We conduct the first global evaluation of turtle biodiversity and imperilment at a suAuthorsJoshua R. Ennen, Mickey Agha, Sarah C. Sweat, Wildredo A. Matamoros, Jeffrey E. Lovich, John B. Iverson, Anders G.J. Rhodin, Robert C. Thomson, H. Bradley Shaffer, Christopher W. HoagstromTurtles and tortoises are in trouble
Turtles and tortoises (chelonians) have been integral components of global ecosystems for about 220 million years and have played important roles in human culture for at least 400,000 years. The chelonian shell is a remarkable evolutionary adaptation, facilitating success in terrestrial, freshwater and marine ecosystems. Today, more than half of the 360 living species and 482 total taxa (species aAuthorsC.B. Stanford, J.B. Iverson, A.G.J. Rhodin, P.P. van Dijk, R.A. Mittermeier, G. Kuchling, Kristin H. Berry, A. Bertolero, K.A. Bjorndal, T.E.G. Blanck, K. A. Buhlmann, R.L. Burke, J.D. Congdon, T. Diagne, T. Edwards, C.C. Eisemberg, J.R. Ennen, G. Forero-Medina, M. Frankel, U. Fritz, N. Gallego-Garcia, A. Georges, J.W Gibbons, S. Gong, E.V. Goode, H.T. Shi, H. Hoang, M.D. Hofmeyr, B.D Horne, R. Hudson, J.O. Juvik, R.A. Kiester, P.V. Koval, M.-A. Lea, P.V. Lindeman, Jeffrey E. Lovich, L. Luiselli, T.E.M. McCormack, G.A. Meyer, V.P. Paez, K. Platt, S.G. Platt, P.C.H. Pritchard, H.R. Quinn, W.M. Roosenburg, J.A. Seminoff, H.B. Shaffer, R. Spencer, J.U. Van Dyke, R.C. Vogt, A.D. WaldeTurtle biogeography: Global regionalization and conservation priorities
Defaunation in the Anthropocene has created a need to focus limited conservation resources on geographically-explicit areas with high conservation significance. Priority conservation areas are often defined as those with high biodiversity – hotspots. While these conservation areas are critical to securing global biodiversity, prevailing approaches for their delineation are often qualitative. Here,AuthorsJoshua R. Ennen, Mickey Agha, Sarah C. Sweat, Wilfredo A. Matamoros, Jeffrey E. Lovich, Anders G.J. Rhodin, John B. Iverson, Christopher W. HoagstromUnderstanding reproductive allometry in turtles: A slippery “slope”
Measures of reproductive output in turtles are generally positively correlated with female body size. However, a full understanding of reproductive allometry in turtles requires logarithmic transformation of reproductive and body size variables prior to regression analyses. This allows for slope comparisons with expected linear or cubic relationships for linear to linear and linear to volumetric vAuthorsJohn B. Iverson, Peter V. Lindeman, Jeffrey E. LovichAn introduced breeding population of Chrysemys picta marginata in the Kaibab National Forest, northern Arizona
The painted turtle (Chrysemys picta) is widely distributed from coast to coast in North America with each of four subspecies generally occupying different regions. In the southwestern USA and northern Mexico, where C. p. bellii is the expected native race, populations are small and widelyscattered. Introduced populations of other painted turtle subspecies are reported from various locations in theAuthorsJeffrey E. Lovich, Bruce L. Christman, Kristy L. Cummings, Jenna Norris, Shellie R. Puffer, Christina JonesWhere has turtle ecology been, and where is it going?
Over 9000 articles have been published on turtles and tortoises (excluding sea turtles) since 1950 according to the Web of Science, including over 8000 contained in a personal bibliography that we analyze in this paper. Research had a slow start from 1900 to 1950, with mostly anecdotal additions to our knowledge until the contributions of F. Cagle and A. Carr took turtle research to new levels asAuthorsJ. Whitfield Gibbons, Jeffrey E. LovichWhere have all the turtles gone, and why does it matter?
No abstract available.AuthorsJeffrey E. Lovich, Joshua R. Ennen, Mickey Agha, J. Whitfield Gibbons - News
Below are news features about turtle and tortoise research led by the Southwest Biological Science Center.
- Partners
Below are partners associated with this project.