|Scientific Name:||Graptemys barbouri|
|Species Authority:||Carr & Marchand, 1942|
|Red List Category & Criteria:||Vulnerable A2bcde ver 3.1|
|Assessor/s:||van Dijk, P.P.|
|Reviewer/s:||Horne, B.D., Mittermeier, R.A., Philippen, H.-D., Quinn, H.R., Rhodin, A.G.J., Shaffer, H.B. & Vogt, R.C|
Graptemys barbouri has been assessed as Vulnerable due to an inferred population decline resulting from overharvesting, habitat degradation, predation and disease. The global population is estimated to be between 1,000 and 10,000 individuals, restricted to a maximum of 20 subpopulations. Graptemys barbouri has been described as reasonably abundant in parts of its range but rare in others. Long-term population comparisons may be interpreted as indicating stable or declining populations, but the large numbers historically collected are no longer encountered. The species may qualify as Endangered if better data are available.
|Range Description:||Graptemys barbouri inhabits the Apalachicola River system and nearby systems of Florida, Georgia, and Alabama in the southeastern United States, including the Chattahoochee river system as far north as Stewart County, GA, the Flint River north to Meriwether Coounty, GA, the Chipola River, and the Choctawhatchee and Pea River systems as far as Geneva Coouty, AL (Iverson 1992, Bonin et al. 2006, Ewert et al. 2006).|
Native:United States (Alabama, Florida, Georgia)
|Range Map:||Click here to open the map viewer and explore range.|
Graptemys barbouri was considered the fourth rarest Graptemys based on extensive basking surveys (Lindeman pers. comm. 2009).
Moler (1986) compared his population survey along the Chipola River to Carr's (1952) observations, and concluded that population trends in the 45 years since the observations by Carr was as compatible with a stable population as with a decline. However, compared to encounter rates of 68.3 turtles/km of river by Sanderson in 1974 during repeated sampling of a 5.65 km section (total of 386 individuals), sighting rates of 2.64 (average) to 5.66 turtles/km by 1986 suggest a substantial decline at least locally. Cagle (1952) collected 393 individuals from an unspecified section of this river.
Numbers along a surveyed section of the Apalachicola River estimate numbers of 350–500 individuals (Zappalorti in Ewert et al. 2006), with Choctawhatchee River estimates a minimum of 250 individuals in the Florida stretch with the highest recorded density as 7.1 turtles/km.The population of G. barbouri is estimated to range between 1,000 and 10,000 individuals, found in 1–20 subpopulations (NatureServe 2006). This species is reportedly abundant in parts of its range, such as the Chipola, Apalachicola, and Flint Rivers, while it is scarce in others. NatureServe (2006) describe the population's short term trend as “declining to stable”.
|Habitat and Ecology:||
Graptemys barbouri favours sections of free-flowing rivers with limestone outcrops, which support good populations of freshwater snails, but use of silty channels is also widespread. (Ewert et al. 2006).The species is essentially carnivorous, with juveniles and males feeding on a variety of insects and small snails, whereas larger females shift to a diet of predominantly freshwater snails with some bivalves also taken. (Ewert et al. 2006).
Females require many years (possibly 14–20 years) to reach maturity at 20 cm carapace length (CL) and 1 kg weight; males mature in three to four years at about 8 cm CL. Females reach their maximum size (largest recorded – 330 mm CL, 3.3 kg) by the age of about 24 years. Males reach only 130 mm CL at about 200 g. Corresponding to the different age to reach maturity, population sex ratios have been recorded as 67–78% males. Hatchlings measure 30–38 mm and weigh up to 13 g (Ewert et al. 2006).
Females have a prolonged nesting season (late April to early August) with rather small clutch size (usually 7–10 eggs/clutch, extremes 3–15) and may produce three to five clutches per year, for an annual reproductive output of 25–40 eggs (Ewert et al. 2006). Nest predation rates are substantial, mainly by raccoons but also fish crows (Ewert et al. 2006).
Graptemys barbouri is threatened by habitat degradation, overharvesting and predation. Local harvesting is thought to continue along the Chipola River (Ewert et al. 2006). Some shooting is thought to still continue.
Channel modification, dredging, barge traffic and pollution threaten its riverine habitat. Increasingly, overgrowth of sandy spoil mound sites for nesting is changing the spatial distribution of nests, with nesting sites becoming ever more clumped, and removal of dead trees or 'snags' removes basking sites (Ewert et al. 2006). Demand for water from the rivers it inhabits is substantial and likely to increase in the future. Few superfund polluted sites are located within or immediately connected to G. barbouri habitat, and the potential of a major industrial spill affecting a significant section of the total population of G. barbouri cannot be discounted. (Ewert et al. 2006).
Eggs and young are heavily predated by raccoons and fish crows, affecting recruitment. Raccoons also kill nesting adult females. To what extent raccoon and fish crow populations near the nesting sites of G. barbouri are subsidized by humans remains unknown (Ewert et al. 2006).
In the Choctawhatchee River system there is indication of introgressive hybridization with G. ernsti, which could locally deplete G. barbouri as a pure form. (Ewert et al. 2006).
Previously Graptemys barbouri was assessed by IUCN (in 1996) as LC/nt under the version 2.3 criteria; as G2, or Vulnerable, by NatureServe in 1996; as G2 (Imperiled) at both global and State level by the Florida Natural Areas Inventory; and as a Species of Special Concern in Florida. Graptemys barbouri is included in CITES Appendix III (United States) since 14th June 2006.
Graptemys barbouri is prohibited from most forms of commercial exploitation in Alabama, Florida and Georgia, and only Florida allows take of up to two individuals for personal use.
Management of subsidized / elevated raccoon and fish crow populations is a challenging prospect but should be considered (Ewert et al. 2006).
Future river management, including commercial barge traffic, recreational boating, snag removal, sand dredging and water usage, and waterfront residential developments, are generally beyond the scope of turtle conservation but turtles should at least be integrated into management plans and practices, and a few specific sites warrant protected status (Ewert et al. 2006).
Research on the population and harvest levels is recommended to identify the rate of past and current decline,Genetic evaluation of the Choctawhatchee map turtles is needed. (Ewert et al. 2006).
|Citation:||van Dijk, P.P. 2011. Graptemys barbouri. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 12 March 2014.|
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