Conservation and Health of Box Turtles in Forest Park and Tyson Research Center
Box Turtle Project Background
Turtle species are disappearing across the globe due to factors that include infectious diseases, habitat destruction, environmental degradation and illegal wildlife trafficking. In the spring of 2012, the Saint Louis Zoo Institute for Conservation Medicine (ICM) launched a project to learn more about native box turtles. We study three-toed box turtles at two primary sites: Forest Park, a large urban park in the middle of St. Louis, and Washington University’s Tyson Research Center, a protected oak-hickory forest 20 miles outside the city and near Eureka, Missouri. We compare the turtle populations at both sites to understand box turtle health and to identify environmental factors impacting the turtles, other wildlife and humans alike.
This project began in 2012 with a few turtles fitted with radio tags so that we could track their movements. As of mid-2020, and with the help of summer interns, we have examined, marked and released over 300 box turtles across the two sites. This includes turtles with radio tags and those marked by filing small V-shaped notches around the edges of their carapaces, or top shells. Through these populations, we are learning about box turtle ecology, movement and health.
Understanding wildlife health is a critical part of conservation; therefore, we conduct health assessments of the turtles in the study annually. This includes a physical exam to document any lesions, injuries or abnormal clinical signs. A small blood sample and cloaca and mouth swabs are collected to determine blood parameters and exposure to pathogens (like bacteria and viruses). When we put all this information together, we can say if the animal is healthy or not, and if not we can even say why. With our years of data collection, we are just beginning to scratch the surface of the work that needs to be done to continue to conserve our state reptile.
To date, we have learned that turtles living in Forest Park (an urban city park) have smaller home ranges than those living at Tyson Research Center (rural forested area) and that mortality (death) is higher for the turtle population in Forest Park than at Tyson Research Center. We also have identified pathogens in some of the box turtles, which, in addition to the baseline health information, we collect (think of a doctor visit and baseline blood values used to see if you are sick!), and we are able to explore health trends in both populations of turtles. Because turtles are long-lived, we are always adding to this long-term data set so we can identify trends and changes. After nine years of following box turtles, we still have much to learn from them and hope to study them for years to come.
The St. Louis Box Turtle Project focuses on education and outreach. The ICM works with area schools to enhance science curricula through hands-on experiences. Students get a taste for field research and data collection by radio tracking turtles alongside scientists. In doing so, the box turtles serve as ambassadors to expose young people to nature. Our hope is to provide children with a better understanding of Missouri’s ecosystems while at the same time cultivating a connection to and empathy for the natural world.
St. Louis Interest
Many St. Louis citizens may not realize that wild, native box turtles reside within Forest Park, or even in other urban parks or in backyards throughout the city. Unfortunately, the number of turtles is declining throughout the entire state of Missouri due to road kills, habitat loss and possibly disease. While the conservation status of box turtles in Missouri is not well understood, we fear they are in trouble in both urban and non-urban areas.
Fun Facts About Box Turtles
Box turtles, like most reptiles, are cold-blooded (ectothermic) and regulate their body temperature by basking in the sun during the cooler morning and evening hours, while seeking shade during hotter times of day. The preferred habitats of Missouri box turtles are prairies, forests and glades. Box turtles get their name from a special hinge on the bottom part of their shell (the plastron) that allows them to close or "box" up as a form of protection against predators. Box turtles are omnivorous and typically eat worms, snails, berries, fungi and arthropods. Species such as box turtles, which have few offspring, are slow-moving and late in maturing, and they are particularly susceptible to human-related extinction.
Missouri has 17 species of turtles, including the ornate and three-toed box turtles, the two main turtles in this study. They can be differentiated mainly by carapace coloration. Ornate box turtles, as their name suggests, have more elaborate shells with orange and yellow lines on a dark background. Three-toed turtles have dull brown-green carapaces that may or may not have yellow line patterns. However, the two species can interbreed to create hybrid individuals. In addition, three-toed box turtles may have four toes! These turtles can live more than 50 years.
St. Louis University Department of Biology
Palmer, J.L., Brenn-White, M., Blake, S., and Deem, S.L. 2019. Mortality of Three-Toed Box Turtles (Terrapene mexicana triunguis) at two sites in Missouri. Frontiers in Veterinary Science. https://doi.org/10.3389/fvets.2019.00412.
Boers, K.L., Allender, M.C., Novak, L.J., Palmer, J., Adamovicz, L., and Deem, S.L. 2019. Assessment of hematologic and corticosterone response in free‐living eastern box turtles (Terrapene carolina carolina) at capture and after handling. Zoo Biology. 1–10. https://doi.org/10.1002/zoo.21518.
Palmer, J.L., Blake, S., Wellehan, J.F., Childress, A., and Deem, S.L. 2016. First reported clinical Mycoplasma sp. infections in free-living three-toed box turtles (Terrapene carolina triunguis) in Missouri. J. Wildl. Dis. 52: 378-382.
Deem, S.L., Palmer, J.L., and Blake, S. 2014. St. Louis Box Turtle Project. Saint Louis Magazine. 30: 20-21.
Palmer, J.L., Deem, S.L., and Blake, S. 2017. Health Threats to Urban and Rural Box Turtles in Missouri. In: 15th Annual Symposium on the Conservation and Biology of Tortoises and Freshwater Turtles. Charleston, SC. August 7-9, 2017. pp. 56-57.