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.
Below are selected publications associated with this project.
Where have all the turtles gone, and why does it matter?
Spatial distribution of estuarine diamond-backed terrapins (Malaclemys terrapin) and risk analysis from commercial blue crab (Callinectes sapidus) trapping at the Savannah Coastal Refuges Complex, USA
Macroecological patterns of sexual size dimorphism in turtles of the world
Global conservation status of turtles and tortoises (order Testudines)
Taxonomy: A history of controversy and uncertainty
Life history with emphasis on geographic variation
Turtles: Freshwater
Hatching success and predation of Bog Turtle (Glyptemys muhlenbergii) eggs in New Jersey and Pennsylvania
Hierarchical, quantitative biogeographic provinces for all North American turtles and their contribution to the biogeography of turtles and the continent
Unusual population attributes of invasive red-eared slider turtles (Trachemys scripta elegans) in Japan: do they have a performance advantage?
Graptemys pearlensis Ennen, Lovich, Kreiser, Selman, and Qualls 2010 – Pearl River Map Turtle
Aspects of the reproductive ecology of female turtles in New Mexico
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.
- Publications
Below are selected publications associated with this project.
Filter Total Items: 42Where have all the turtles gone, and why does it matter?
Of the 356 species of turtles worldwide, approximately 61% are threatened or already extinct. Turtles are among the most threatened of the major groups of vertebrates, in general, more so than birds, mammals, fishes or even the much besieged amphibians. Reasons for the dire situation of turtles worldwide include the familiar list of impacts to other species including habitat destruction, unsustainAuthorsJeffrey E. Lovich, Joshua R. Ennen, Mickey Agha, J. Whitfield GibbonsSpatial distribution of estuarine diamond-backed terrapins (Malaclemys terrapin) and risk analysis from commercial blue crab (Callinectes sapidus) trapping at the Savannah Coastal Refuges Complex, USA
The diamond-backed terrapin (Malaclemys terrapin) is a small estuarine turtle distributed along the Atlantic and Gulf Coasts of the USA. Terrapin populations are declining throughout their range and one of the main causes is mortality by drowning as bycatch in commercially-fished blue crab (Callinetes sapidus) traps (aka pots). We conducted head counts of terrapins and documented the distributionAuthorsJeffrey E. Lovich, Meagan Thomas, Kirsten E. Ironside, Charles B. Yackulic, Shellie R. PufferMacroecological patterns of sexual size dimorphism in turtles of the world
Sexual size dimorphism (SSD) is a well-documented phenomenon in both plants and animals; however, the ecological and evolutionary mechanisms that drive and maintain SSD patterns across geographic space at regional and global scales are understudied, especially for reptiles. Our goal was to examine geographic variation of turtle SSD and to explore ecological and environmental correlates using phyloAuthorsMickey Agha, Joshua R. Ennen, A. Justin Nowakowski, Jeffrey E. Lovich, Sarah C. Sweat, Brian D. ToddGlobal conservation status of turtles and tortoises (order Testudines)
We present a review and analysis of the conservation status and International Union for Conservation of Nature (IUCN) threat categories of all 360 currently recognized species of extant and recently extinct turtles and tortoises (Order Testudines). Our analysis is based on the 2018 IUCN Red List status of 251 listed species, augmented by provisional Red List assessments by the IUCN Tortoise and FrAuthorsAnders G.J. Rhodin, Craig B. Stanford, Peter Paul van Dijk, Carla Eisemberg, Luca Luiselli, Russell A. Mittermeier, Rick Hudson, Brian D. Horne, Eric Goode, Gerald Kuchling, Andrew Walde, Ernst H. W. Baard, Kristin H. Berry, Albert Bertolero, Torsten E. G. Blanck, Roger Bour, Kurt A. Buhlmann, Linda J. Cayot, Sydney Collett, Andrea Currylow, Indraneil Das, Tomas Diagne, Joshua R. Ennen, Germán Forero-Medina, Matthew G. Frankel, Uwe Fritz, Gerardo García, J. Whitfield Gibbons, Paul M. Gibbons, Gong Shiping, Joko Guntoro, Margaretha D. Hofmeyr, John B. Iverson, A. Ross Kiester, Michael Lau, Dwight P. Lawson, Jeffrey E. Lovich, Edward O. Moll, Vivian P. Páez, Rosalinda Palomo-Ramos, Kalyar Platt, Steven G. Platt, Peter C. H. Pritchard, Hugh R. Quinn, Shahriar Caesar Rahman, Soary Tahafe Randrianjafizanaka, Jason Schaffer, Will Selman, H. Bradley Shaffer, Dionysius S. K. Sharma, Shi Haitao, Shailendra Singh, Ricky Spencer, Kahleana Stannard, Sarah Sutcliffe, Scott Thomson, Richard C. VogtTaxonomy: A history of controversy and uncertainty
No abstract available.AuthorsJeffrey E. Lovich, Kristen HartLife history with emphasis on geographic variation
Every organism is defined by a set of vital rates that evolve to enhance lifetime reproductive fitness and survival of individuals and their progeny. These traits vary due to the complex but sometimes predictable interactions between individuals, populations and their environments. Collectively, these attributes are referred to as life history traits and include age and size of maturity, longevityAuthorsJeffrey E. Lovich, J. Whitfield Gibbons, Kathryn GreeneTurtles: Freshwater
With their iconic shells, turtles are morphologically distinct in being the only extant or extinct vertebrate animals to have their shoulders and hips inside their rib cages. By the time an asteroid hit the earth 65.5 million years ago, causing the extinction of dinosaurs, turtles were already an ancient lineage that was 70% through their evolutionary history to date. The remarkable evolutionary sAuthorsJ. Whitfield Gibbons, Jeffrey E. Lovich, R.M. BowdenHatching success and predation of Bog Turtle (Glyptemys muhlenbergii) eggs in New Jersey and Pennsylvania
Nest-site selection by most turtles affects the survival of females and their offspring. Although bog turtles (Glyptemys muhlenbergii) do not typically leave their wetlands for nesting, nest-site selection can impact hatching success and hatchling survival. Between 1974 and 2012, we monitored the fates of 258 bog turtle eggs incubated in the field and 91 eggs incubated under laboratory conditionsAuthorsRobert T. Zappalorti, Annalee M. Tutterow, Shannon E. Pittman, Jeffrey E. LovichHierarchical, quantitative biogeographic provinces for all North American turtles and their contribution to the biogeography of turtles and the continent
Our study represents the first attempt to describe biogeographic provinces for North American (México, United States, and Canada) turtles. We analyzed three nested data sets separately: (1) all turtles, (2) freshwater turtles, and (3) aquatic turtles. We georeferenced North American turtle distributions, then we created presence–absence matrices for each of the three data sets. We used watershed uAuthorsJoshua R. Ennen, Wilfredo A. Matamoros, Mickey Agha, Jeffrey E. Lovich, Sarah C. Sweat, Christopher W. HoagstromUnusual population attributes of invasive red-eared slider turtles (Trachemys scripta elegans) in Japan: do they have a performance advantage?
The slider turtle (Trachemys scripta Thunberg in Schoepff, 1792) is native to the USA and Mexico. Due to the popularity of their colorful hatchlings as pets, they have been exported worldwide and are now present on all continents, except Antarctica. Slider turtles are well-established in Japan and occupy aquatic habitats in urban and agricultural areas, to the detriment of native turtles with whicAuthorsMari Taniguchi, Jeffrey E. Lovich, Kanako Mine, Shintaro Ueno, Naoki KamezakiGraptemys pearlensis Ennen, Lovich, Kreiser, Selman, and Qualls 2010 – Pearl River Map Turtle
The Pearl River Map Turtle, Graptemys pearlensis (Family Emydidae), is a moderate-sized aquatic turtle endemic to the Pearl River drainage of Louisiana and Mississippi. This taxon has long been a cryptic species, as it was considered part of G. pulchra before 1992 and part of G. gibbonsi until 2010. Graptemys pearlensis exhibits sexual dimorphism, with adult females being considerably larger (caraAuthorsJoshua R. Ennen, Jeffrey E. Lovich, Robert L. JonesAspects of the reproductive ecology of female turtles in New Mexico
Data on reproductive ecology of turtles in New Mexico are limited, and some species living there are among the least studied in the United States. We trapped 4 native species of turtles (Apalone spinifera, Chrysemys picta, Pseudemys gorzugi, and Trachemys gaigeae gaigeae) in the Rio Grande and Black River (Pecos River drainage) of New Mexico in June 2012 and 2013 to collect data on female reproducAuthorsJeffrey E. Lovich, Mickey Agha, Charlie Painter, Levi Cole, Austin Fitzgerald, Kevin Narum, Randy Jennings - 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.