|Scientific Name:||Graptemys gibbonsi|
|Species Authority:||Lovich & McCoy, 1992|
Previously considered to encompass the Broad-headed Map Turtles inhabiting the Pascagoula and Pearl river systems, Graptemys gibbonsi was reduced in scope when the Pearl River form was described as a separate species, G. pearlensis Ennen, Lovich, Kreiser, Selman & Qualls, 2010.
|Red List Category & Criteria:||Endangered A2bce+4ce ver 3.1|
|Assessor(s):||van Dijk, P.P.|
Available information indicates that populations of Graptemys gibbonsi have declined by 80–90% since 1950, a time period probably representing 2–3 generation lengths. While the worst impacts from pollution and habitat destruction have apparently become less severe, habitat quality has not been restored to optimal conditions while impacts from wanton destruction, and hurricane aftermath continue to be of concern. The sympatric G. flavimaculata is currently listed as Vulnerable, while population declines of G. gibbonsi have been more severe. Thus Graptemys gibbonsi qualifies as Endangered A2bce+4ce. Also, because of the total length of potentially available river area totals 760 km, and not all of this is suitable or occupied, it almost meets the EN B2 criterion. Graptemys gibbonsi (then including pearlensis) was last evaluated, as LR/nt, in 1996.
Graptemys gibbonsi is restricted to the Pascagoula River system of Mississippi, USA (Ennen et al. 2010). Its total range comprises about 760 km of river: Pascagoula = 130 km, Leaf = 290 km, Chickasawhay = 340 km.
Native:United States (Mississippi)
|Estimated area of occupancy (AOO) - km2:||500|
|Continuing decline in area of occupancy (AOO):||Yes|
|Extreme fluctuations in area of occupancy (AOO):||No|
|Estimated extent of occurrence (EOO) - km2:|
|Range Map:||Click here to open the map viewer and explore range.|
Graptemys gibbonsi (including G. pearlensis at that time) was considered the second rarest Graptemys species by Lindeman (pers. comm 6 Aug 2009) based on extensive basking surveys.
The species used to be observed/captured (in the 1950s–1960s) in about an equal ratio to the sympatric species G. flavimaculata, whereas since the 1990s it has been observed in a one (gibbonsi) to five (flavimaculata) ratio (Lindeman pers. comm 6 Aug 2009). The total population density of flavimaculata has also declined significantly in the same period. This steep decline was attributed to water pollution impacting mollusc populations on which this species feeds. The only density estimate available is 34 animals per river km (significantly less than G. flavimaculata at 80–120 animals/km) (Sellman and Qualls 2009).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||
Graptemys gibbonsi primarily inhabits large to medium-sized rivers with log and snag basking sites, sandy beach nesting sites, and substantial molluscan prey populations. Clear water is preferred and polluted and saline water conditions are apparently avoided (Lovich et al. 2009).
Males and small females are predominantly insectivorous, while large females feed predominantly on freshwater snails and clams.
Females reach up to 29.5 cm carapace length (CL) at 3.15 kg, males to 12.4 cm CL at 340 g.
Smallest reported gravid female was 17.9 cm CL, average of eight gravid females was 22.4 cm in the Leaf River. Maturity was estimated to be reached at age 15–20 years by females, males probably at a younger age, possibly as young as four years (Selman in Lovich et al. 2009, Cagle in Ernst and Lovich 2009). Generation length has not been determined but is unlikely to be shorter than 25 years.
Average clutch size has been reported as 7.5 eggs, and multiple nesting is likely (McCoy and Vogt in Lovich et al. 2009). Hatchings measure about 39 mm CL (Selman in Lovich et al. 2009).
|Generation Length (years):||25|
|Use and Trade:||Collected for the pet trade.|
Recorded declines of G. gibbonsi have been attributed to water pollution impacting mollusc populations on which they feed, snag and log removal, channelization and impoundment, as well as collection for the pet trade, wanton destruction by fishermen and others, and potentially by subsidized predators (i.e., unnaturally large populations of predators subsidized by easily available resources near human settlements) increasing nest predation rates.
Riverine pollution was particularly significant in parts of the Pascagoula River system, including the Leaf River, as a result of riverside paper industries, municipal run-off, and riverine gravel mining (review in Lovich et al. 2009), and while pollution levels have improved, they remain of concern. In addition, the river has suffered significant impact from hurricanes in recent years.
Graptemys gibbonsi is protected from commercial exploitation in Mississippi and possession is limited to four individuals. It is included in CITES Appendix III (United States) since 14 June 2006. Graptemys gibbonsi has been suggested to qualify for inclusion as threatened under the Endangered Species Act (ESA) (Lindeman 1999, Selman and Qualls 2007 in Lovich et al. 2009).
Lovich et al. (2009) stated that appropriate conservation measures for the species include:
|Citation:||van Dijk, P.P. 2013. Graptemys gibbonsi. The IUCN Red List of Threatened Species 2013: e.T184436A8275938. . Downloaded on 26 June 2016.|
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