Turtles play a role in environmental health
Last summer, two rising second-year veterinary students traded blue lab coats and lecture halls in Urbana for chest-high waders and wetlands in Lake County in northeast Illinois. Working as part of the Wildlife Epidemiology Lab at the University of Illinois College of Veterinary Medicine, Lauren Mumm and John Winter joined the Blanding’s Turtle Recovery Program, operated by the Lake County Forest Preserve.
Mumm, from Rogers, Minn., and Winter, from Fort Myers, Fla., braved “swamp foot” (infected toes), deceptively deep marshes, and turtle pee (which managed to baptize everything from their gear to their waders and even their phone) to help evaluate the health status and disease threats of this declining species. And every week of the summer, they wrote a blog to showcase their adventures.
Below is their blog post from June 5, entitled “Meet the Turtles.” Read all their posts at: vetmed.illinois.edu/wel/.
Blanding’s Turtle: Habitat and Diet
The Blanding’s turtle (Emydoidea blandingii) comes from the family Emydidae, which consists of pond turtles such as red-eared sliders and painted turtles. Blanding’s turtles are classified as semi-aquatic turtles, meaning they divide their time between water and the land between wetlands.
They prefer shallow waters not much more than a few feet deep, leaving deeper ponds and lakes to more aquatic species like their cousins, the painted turtle. Theory suggests that Blanding’s turtles are not as competent swimmers relative to species that thrive in deeper waters. Females are known to travel great distances to find a suitable nesting site as well as look for new habitat and resources. Many times this summer when we find Blanding’s turtles they tend to be basking on dirt or dead brush piles in or around these shallow ponds and marshes.
This specimen displays the species’ characteristic “smile.”Blanding’s are omnivorous, meaning that their diets consist of both plant and animal material. From the shallow ponds they inhabit, they consume small fish, crustaceans such as crayfish, insects, and frogs. They also will eat vegetation surrounding the ponds, such as berries and plant matter.
Blanding’s Turtle: Appearance
Unique characteristics of the Blanding’s turtle include its coloration, shape, and of course its signature smile. A Blanding’s turtle has a dark brown/black shell, sometimes with bright yellow spots on the carapace (top shell), providing good camouflage in the more heavily vegetated areas. Its head and legs are also dark, while its chin and throat is a bright, vibrant yellow. Its carapace is more domed than that of the painted turtles with whom it shares ponds, and tends to dome more with age.
A unique feature the Blanding’s turtle is its curved mouth, which is shaped so that edges of the top beak curl upward, endowing these turtles with a deep smile.
Blanding’s Turtle: Survival
Throughout much of its natural range (the Great Lakes region), the Blanding’s turtle is listed as threatened or endangered on the IUCN Red List. (The IUCN Red List of Threatened Species™, put out by the International Union for Conservation of Nature, is widely recognized as the most comprehensive, objective global approach for evaluating the conservation status of plant and animal species.)
The main causes of population decline include habitat loss and fragmentation from human development, genetic diversity loss due to small population size, small numbers of turtles living to reproductive age, and predators. Human development and ecological imbalance, such as an abundance of beavers, has destroyed or altered areas where Blanding’s turtles live. For example, in Illinois, dwindling numbers of large predators has led to an increase in the beaver population. Beavers make dams, creating deeper ponds with little water flow and pushing out the Blanding’s turtles, which prefer shallower areas.
Another reason it is hard for Blanding’s turtles to survive in disturbed areas is their delayed maturation: they reach reproductive age at 14 to 20 years. In many areas, too few juveniles live to adulthood to sustain a healthy adult population.
Major predators to turtles in general are raccoons, skunks, crows, and foxes. An abundance of predators negatively affects the survival rate of our Blanding’s turtle friends. Some of the turtles we have encountered this summer have had signs of predator encounters, including what appears to be bites taken from shells or scarred/damaged appendages. Data from the Lake County Forest Preserve show that between 2004 and 2010, less than 8 percent of Blanding’s turtle nests avoided destruction by raccoons or other predators, unless the nests were protected by human intervention.
Blanding’s Turtle: Role in Ecosystem Health
So why care about saving an endangered species? Biodiversity! It is important that we conserve and save native plants and animals to prevent extinction of natural ecosystems. Losing a single species can result in a detrimental domino effect on the rest of the ecosystem in which that species resides.
Most significantly, species loss will affect the natural food chain. Each species contributes to maintaining a healthy equilibrium of all populations and resources that even we humans rely on. Ecosystem equilibrium can prevent invasive species development as well as movement into new habitats, such as predators moving into residential areas. The thought of raccoons and coyotes moving into local neighborhoods is unappealing to many people. Preserving Blanding’s turtles, as well as other threatened and endangered species, is crucial to environmental health and stability.