- Federal Status: Not Listed
- FL Status: State-designated Threatened
- FNAI Ranks: G2/S2 (Imperiled)
- IUCN Status: NT (Near Threatened)
The Barbour’s map turtle is the largest species of map turtle. Shell length for the species differs by sex. Female shells can grow up to 11 inches (28 centimeters), while male shells can grow up to six inches (15.2 centimeters) (Florida Natural Areas Inventory 2001). This species has a gray oval-shaped shell with two to four individual spikes along the vertical center of the upper shell (carapace) (Ewert et al. 2006). These spikes become worn down to knobs on female shells. The large head is used to crush mollusks. This species also has black-and-green striped skin with a yellow mark on or below the chin (Florida Natural Areas Inventory 2001).
The diet of the Barbour’s map turtle primarily consists of mollusks and insects.
Nesting occurs from April to early August. This species prefers loose sandy areas for nesting; however, other micro-habitats are used for nesting along the Chipola River because the preferred nesting habitat cannot be found there. Barbour’s map turtles are capable of laying several clutches per year, with each clutch containing seven to ten soft-shelled eggs (Ewert et al. 2006). The total incubation period for a map turtle can range from 60-75 days (Kirkpatrick 1993). The sex of the offspring is determined by the surrounding environmental temperature of the egg. A steady incubation temperature of 77°F (25°C) will result in a male hatchling, while a temperature of 84.2-86°F (29-30°C) will result in a female hatchling (Ewert et al. 2006). Females require as long as 12 years to attain sexual maturity, whereas males only require three to four years (Sanderson 1974).
The Barbour’s map turtle inhabits lotic (rapid flowing) waters, from moderately broad alluvial rivers (river with a bed and bank of mobile sediment) with relatively low clarity, such as the lower Apalachicola River, to clear, spring-fed streams such as Dry Creek and Spring Creek in Jackson County. In rivers, the species typically occurs along mainstream channels and makes little use of quiet floodplain waters. Calcareous tributaries (waterways that contain calcium carbonate sediments) may support substantial populations. They can be found in the Aucilla, Ochlockonee, Apalachicola, Chipola and Choctawhatchee rivers in Florida and other waterways that features their habitat requirements (Jackson 2003). Barbour’s map turtles are also found in the Pea River in Alabama, and the Chattahoochee and Flint River in Alabama and Georgia (Florida Natural Areas Inventory 2001, Map Data from: Krysko et al. 2011).
Because rivers in Florida are relatively stable and persistent, riverine species like the Barbour’s map turtle are less profoundly threatened by habitat destruction than much of the state’s herpetofauna. Nonetheless, various human-generated threats to the integrity of lotic systems, including their floodplains, affect Florida’s riverine turtles (Jackson 2005). The threat of chemical pollution (from industry, cities, boats, or highways) is especially dangerous to a species such as the Barbour’s map turtle that is confined to very few river systems, with but a single system (Apalachicola) harboring the vast majority of individuals. The problem is compounded by the Apalachicola River receiving pollutants from Georgia and Alabama. In non-impounded sections of the Apalachicola River, channel maintenance operations for shipping have altered the river bottom profile, removed preferred basking sites (snags) essential to Barbour’s map turtle, covered nesting sites with sediment (though incidentally creating new sites), and altered natural hydrological regimes in the floodplain (Ewert and Jackson 1994). Barbour’s map turtles also face the natural threat of the destruction of their nests by raccoons and fish crows (Ewert et al. 2006). Boat strikes, though difficult to detect, may be a significant source of mortality in some areas more heavily used by man; large females are particularly vulnerable. Barbour’s map turtles were hunted in the past; however, rule 68A-27.005 of the Florida Administrative Code makes it illegal to take, possess, or sell the Barbour’s map turtle.
Ewert, M. A. and D. R. Jackson. 1994. Nesting ecology of the alligator snapping turtle (Macroclemys temminckii) along the lower Apalachicola River, Florida. Florida Game and Freshwater Fish Commission, Nongame Wildlife Program Report NC89-020, Tallahassee, Florida, USA. 45pp.
Ewert, M. A., P. C. H. Pritchard, and G. E. Wallace. 2006. Graptemys barbouri – Barbour’s map turtle. Pages 260–272 in P. A. Meylan, editor. Biology and conservation of Florida turtles. Chelonian Research Monographs No. 3.
Florida Natural Areas Inventory. 2001. Field guide to the rare animals of Florida.
Jackson, D. R. 2005. Florida rivers and turtles: an interdependence. Pages 163–168 in W. E. Meshaka, Jr. and K. J. Babbitt, editors. Amphibians and reptiles: status and conservation in Florida. Krieger Publishing Company, Malabar, Florida, USA. 318pp.
Jackson, D. R. 2003. Geographic distribution. Graptemys barbouri. Herpetological Review 34:164.
Kirkpatrick, D. T. 1993. An Overview of the Map Turtles of the United States. Retrieved 14 June, 2011, from Dr. David T. Kirkpatrick Molecular Geneticist and Turtle-Fancier
Krysko, K., K. Enge, and P. Moler. 2011. Graptemys barbouri Carr and Marchand 1942 Barbour’s map turtle. Atlas of Amphibians and Reptiles in Florida.
Sanderson, R. A. 1974. Sexual dimorphism in the Barbour’s map turtle, Malaclemys barbouri (Carr and Marchand). Master of Arts Thesis, University of South Florida, Tampa. 94pp.