ALABAMA HAS REMARKABLE TURTLE BIODIVERSITY

by Whit Gibbons

November 1, 2015

Turtles of the Southeast may be brought to mind at any time because of their annual habits. Most mate in the spring, so males are seen moving about in search of females. All but two kinds lay eggs in spring or summer, so females on their way to or from nesting sites are often seen crossing roads, golf courses, even people's yards.

Turtles are prevalent in autumn when the babies of many species hatch and emerge from eggs laid in underground nests. Even in winter, a few of the aquatic species can be seen basking on logs or large rocks during warm sunny days in many southeastern lakes, rivers and reservoirs.

The Southeast has the highest turtle biodiversity in North America, and Alabama has more species than any other state. As a result of equable climate, complex geology and a rare combination of major rivers and tributary streams leading into coastal estuaries, the Mobile Basin is internationally known among turtle biologists. That area has one of the highest counts of turtle species diversity in the world.

A recently published book"Turtles of Alabama" (2015, University of Alabama Press) by Craig Guyer, Mark A. Bailey and Robert H. Mount is ideal for learning about any turtle native to Alabama, which includes the majority of turtles found in the United States.

Among the turtles native to Alabama, albeit only as occasional visitors in the case of sea turtles, are 35 recognized species belonging to seven distinct families. The authors discuss identifying characteristics, ecology and behavior, and distribution throughout the state, as well as issues related to conservation and management of each species of turtle.

The written description of each species is accompanied by a photograph of an adult. For many species, a photograph of a hatchling, which can sometimes look different from the adult, is also included, aiding further in identification. Another tool to assist with identifying species is the geographic range, which can often narrow the field of what has been found in a particular locality. Each species account has a map showing localities where specimens of each kind have been documented, plus a U.S. map showing the range of the species in other states.

Alabama's turtles are represented by two families that include only a single species found in the state, or anywhere in the Southeast. These are the leatherback sea turtle and the gopher tortoise.

The leatherback is the largest living species of turtle in the world, reaching lengths of up to 8 feet. When they crawl onto a beach, the tracks can be 6 feet wide, wider than that of any other turtle. Leatherbacks have been seen in Gulf waters, and according to the book "rare instances of stranded adults" have been documented for Alabama.

The gopher tortoise is likewise a distinctive species but with a dramatically different ecology. Tortoises of the world belong to a single family and are native to all of the warm continents except Australia, but only one species is found in the coastal states of the Southeast, from South Carolina to Louisiana.

The gopher tortoise is found throughout much of Florida but in Alabama is restricted mostly to the southern third of the state. This intriguing tortoise is noted for living in large colonies and digging deep underground burrows in sandy soil.

Some of these subterranean retreats are "up to 30 feet in length and more than 15 feet deep" and many serve as important refuges for other animals. In Alabama west of the Tombigbee River, the gopher tortoise is officially protected as a threatened species under the Endangered Species Act.

Alabama has almost three dozen species of turtles, including the giant alligator snapping turtles, each of which is unique in its own ecology and behavior. The information found in "Turtles of Alabama" will be useful to anyone who wants to learn more about turtles, no matter where they occur in the southeastern United States.

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