Distribution, Abundance, and Status of Barbour's Map Turtle (Graptemys barbouri) in Florida

Abstract

We collected information to determine the status of Barbour's map turtle (Graptemys barbouri) in Florida by conducting standardized surveys of occupied watersheds in 2014–2015, including the Choctawhatchee, Chipola, Apalachicola, and Ochlockonee rivers. Single-pass basking surveys were used to determine the distribution and relative abundance of G. barbouri. Multiple-pass basking surveys and N-mixture modeling were used in sections of the Apalachicola and Ochlockonee rivers to estimate detectability and abundance of map turtles. Observed counts were compared with available information from previous surveys to make inferences about population change. A total of 5917 G. barbouri observations were recorded during single-pass surveys along 502 river kilometers (rkm) and we expanded the documented range by 76 rkm. Further, we used multiple-pass surveys to estimate 2079 G. barbouri along six 2-km sections (12 km total) of the Apalachicola River (173.3 turtles/rkm) and 292 G. barbouri along five 5-km sections (25 km total) of the Ochlockonee River (11.7 turtles/rkm). The present study is the most comprehensive distributional survey for G. barbouri in Florida to date. The species was documented for the first time in 2 counties and observed counts were consistently higher than in previous surveys. Overall, the Florida population appears secure with evidence of expansion in both the Choctawhatchee and Ochlockonee drainages.