Bog Turtle (Glyptemys muhlenbergii)
Learn about The Nature Conservancy's work to save North America's smallest turtle.
Common name: Bog turtle
Scientific name: Glyptemys muhlenbergii
Conservation status: Critically Endangered (IUCN)
Lifespan: Oldest documented bog turtle was 61 years old
Size: 4.5 inches maximum length
Meet the Bog Turtle
The bog turtle is North America’s smallest turtle, growing only to 4.5 inches in length. Easily recognized by the orange patch on either side of its head, the bog turtle favors open, groundwater-fed wet meadows and bogs dominated by tussock sedge and grasses.
Bog turtles thrive in mountain bogs, or isolated wetlands with acidic, wet soil, thick moss and deep layers of mud. These deep mucky soils, fed by groundwater, provide protection from predators and other elements. Short clumps of vegetation let in plenty of sunlight for incubating eggs and basking. If any of these conditions change, a bog turtle population can decline and may eventually disappear from the area.
Northern and Southern Populations
The bog turtle occurs only in the eastern United States, with distinct northern and southern populations separated by a 250-mile gap through most of Virginia and West Virginia. The northern population is larger than the southern, with bog turtles occurring in eastern Pennsylvania, southern New York and most of New Jersey and extending as far north as Massachusetts. Although populations were once abundant in the Southern Blue Ridge of North and South Carolina and Georgia, the bog turtle is now facing unprecendented challenges to its survival.
Threats to Bog Turtles
The bog turtle is classified as federally-threatened on the U.S. Fish and Wildlife Service’s Endangered Species List.
Habitat loss and fragmentation and forest succession represent the primary reasons for the decline of this species. In the past, bog turtles could move to nearby habitat if conditions changed. However, remaining habitats have become more isolated because of land development.
Loss of critical mountain bog habitat poses a major threat to the southern population of bog turtles, which tend to occur at higher altitudes than the northern population. Mountain bogs are important for a variety of reasons. In addition to the bog turtle, bogs provide homes for four endangered species, including green pitcher plants, mountain sweet pitcher plants, swamp pink, and bunched arrowhead. Migratory birds such as woodcock, grouse, turkey and wood duck stop in for a visit. They are also valuable breeding habitat for amphibians, particularly for salamanders. The Southern Appalachians are a hotspot for salamanders unequaled anywhere else in the country. There are also benefits to people. Bogs regulate water flow. When it floods, they will soak up water, which is gradually released to streams.
Bog turtles are also threatened by diminished water quality, mortality on roadways, growing populations of predators like raccoons and by reptile collectors who consider this rare turtle a valuable prize. Adam Warwick, TNC’s Southern Blue Ridge Stewardship Manager, explains the risk of exposing bog turtles to the illegal pet trade. “If someone took a picture of a bog turtle and posted it on Instagram with the geolocation, a poacher could come in and wipe out a single bog turtle population in one night.”
How TNC is Protecting Bog Turtles
In Pennsylvania, small, spring-fed streams trickle down South Mountain towards the sandstone valley below. In some areas, the water collects to form soft, muddy wet meadows, surrounded by clumps of grassy tussock sedges and other low-lying vegetation. This creates ideal habitat for bog turtles.
In 1989, The Nature Conservancy acquired land near South Mountain in order to maintain, and restore habitat required by these turtles that are no larger the palm of a human hand. Over the years, this work has included managing burns, cutting trees and introducing cattle and goat grazing in order to foster the growth of native vegetation and maintain the soft mucky soils that the turtles prefer.
TNC also conducted a radio telemetry study in Pennsylvania that documented bog turtle locations, hibernation, travel patterns and habitat use within the preserve. Studies have revealed the existence of a 61-year-old bog turtle, the oldest documented bog turtle known in the wild.
Many mountain bogs that used to be home to bog turtles in the southern population have been lost to development. There, Warwick leads the charge to restore mountain bog habitat for the turtle. “The work we do spans acquisition and protection, to management of habitat, to bolstering population,” he explains.
Beavers also once helped to create that habitat in the Southern Blue Ridge, but with their populations also in decline, TNC strives to maintain an open, grassy landscape with clear cutting. Electric fencing and caging at bog turtle sites to protect them from predators and people are techniques known techniques to enhance nesting success.