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.

Abstract

The Pascagoula map turtle (Graptemys gibbonsi) and Pearl map turtle (Graptemys pearlensis) were first separated from the Alabama map turtle (Graptemys pulchra) in 1992 under the former name and subsequently recognized as 2 separate species in 2010. The possibility that they should be listed under the Endangered Species Act was raised 7 yrs after separation from G. pulchra, when basking surveys showed that at most sites they were considerably less abundant than 2 sympatric congeners listed as threatened: the Pearl River drainage's ringed sawback (Graptemys oculifera, listed in 1986) and the Pascagoula River drainage's yellow-blotched sawback (Graptemys flavimaculata, listed in 1991). Historical data also indicated that the sympatric species pairs may once have been more similar in abundance. Now, more than 2 decades later, G. gibbonsi and G. pearlensis are candidates for listing. From 2015 to 2018, we surveyed basking turtles in point counts and in jon boat and canoe surveys and conducted trapping at several sites to ascertain the status of the 2 candidate species. Data were also combined with similar data collected between 2006 and 2014. Despite their similarity morphologically and in their basic ecology, 3 important differences are pertinent to the question of whether the 2 candidate species should be federally protected. First, their river systems are geomorphically very different. The medium-size to large tributary streams that the 2 species inhabit are a considerably more prominent feature of the Pascagoula drainage than the Pearl drainage and may insulate populations from potential threats on the main stems. Second, G. gibbonsi inhabited 35% more stream reach, had 22% higher catch per unit effort, and were recorded at 44% higher numbers in point counts and 3% higher numbers in basking density surveys than G. pearlensis. Coarse-scale estimates of each species' global populations suggest that G. gibbonsi is ∼ 1.56 times as abundant as G. pearlensis overall. Third, the reasons for the listing of each species' sympatric sawback congener are very different: G. oculifera of the Pearl drainage was listed primarily due to existing and imminent but as-yet-unrealized habitat modification, while G. flavimaculata of the Pascagoula drainage was listed primarily due to perceived low populations, particularly in upper portions of the drainage, and concerns regarding water quality. We conclude that G. pearlensis warrants conservation protection via a listing as threatened, while G. gibbonsi should be listed either as threatened or as threatened by similarity of appearance. For G. gibbonsi, the former option would recognize a long-term historical decline in its relative abundance suggested by trapping data from the 1950s through 1970s, while the latter would recognize its less imperiled status and protect it from the pet trade while focusing recovery efforts on G. pearlensis.

Abstract

The impacts of human modifications of rivers and associated riverine fauna are well documented, especially following the construction of impoundments. In the Pearl River system of Mississippi and Louisiana, 2 endemic Graptemys species are found (G. oculifera; G. pearlensis), but little is known of their densities in urban segments near Jackson, Mississippi, even though both are species of conservation concern. I used spotting scopes and binoculars to complete replicated basking surveys for both Graptemys species during the summers of 2017 and 2018 in 5 equidistant segments of the Pearl River and nearby oxbow lakes. Basking densities for both species were generally higher in river segments upstream and downstream of Jackson compared to middle segments. Graptemys oculifera were found in greater densities than G. pearlensis in all segments (14–69-times higher). Graptemys oculifera was found in 4 of the 6 oxbow lakes surveyed, but mean densities decreased 10-fold compared with river segments; G. pearlensis was absent from all oxbow lakes. Densities for a generalist turtle species, Trachemys scripta, increased 35 times in oxbow vs. river habitats. The middle 3 survey segments (∼ 15.9 river kilometers) are inclusive of a proposed river impoundment project—the One Lake Project—for flood control and economic development. Estimates of direct and indirect impacts of this project are sizeable for G. oculifera (direct impact: 1684; indirect: 2129) while estimates for G. pearlensis are lower (direct: 88; indirect: 219). The One Lake Project would surely alter existing riverine processes and will favor generalist turtles such as T. scripta that prefer nonflowing lake settings at the expense of riverine Graptemys species. The One Lake Project would be a major setback to both Graptemys species in and around the project area and would negatively impact the recovery potential of both species.

Editorial Introduction. — This section is devoted to poetry involving turtles, representing either reprinted previously published or new unpublished material. We encourage our readers to submit poetry or songs for consideration, either their own material or work by other authors. Poems may be submitted to Anders G.J. Rhodin, Chelonian Research Foundation, E-mail: RhodinCRF@aol.com.

Our desire is to share with our readers the beauty and wonder of turtles as expressed through the art of the poem or song. In the sense that the relationship between man and turtles is multifaceted, so too is turtle poetry. The poems we publish here