Bartsch's iguana
Cyclura carinata bartschi
By Sandra Buckner and David Blair
Description
Bartsch's iguana is greenish to brownish-gray, with a yellow dorsal crest, faint yellow-brown reticulations on the bodies of the adults, and a golden iris (Auffenberg 1976). Large specimens are approximately 770mm total length. Schwartz and Carey (1977), who examined nine specimens (seven in life), recorded an SVL of 335mm in the largest male and 285mm in the largest female. They state, "in general their body colors seem to be somewhat paler (tending towards creams to pale grays) than those of nominate carinata (gray to dull tan)." As this subspecies has not been studied in the field, the paler body color may be accounted for by temperature or time of year when specimens were observed.
Distribution
This subspecies is restricted to Booby Cay, located 0.5km off the eastern end of the island of Mayaguana in the southern Bahamas. The cay is 2km in length, approximately 750m wide at its northeastern end, narrowing to less than 100m, and again widening to approximately 250m at its southwestern end. Approximately 30% of the cay is taken up by two ponds. Iguanas probably originally ranged over the entire cay but were likely concentrated on the eastern half where the vegetation was more dense. There are historical anecdotal references to the presence of iguanas on Mayaguana. However, there have been no recent sightings on the island, which has an area of 285km2 and a human population of approximately 500 concentrated on the western half. There are no roads extending to the eastern end of the island and it is conceivable that iguanas still exist in this area.
Status of population in the wild
Surveys indicate that iguanas were fairly numerous in 1988 and 1997 with all age classes present, indicating a healthy reproducing population. However, this subspecies is restricted to one population on a single small cay with a high point of 6.2m and most of its area below 3m. Although no census has been conducted, it is unlikely that the population exceeds 500 animals, and is estimated to be between 200 and 300 (Blair 1991a; Bendon 1997).
Ecology and natural history
No research has been conducted on this subspecies. Like the Turks and Caicos iguana, this subspecies is primarily herbivorous throughout life, although insects, mollusks, crustaceans, arachnids, lizards, and carrion are occasionally consumed. Burrows or crevices in or under rocks are used for retreat.
Habitat
Like the Turks and Caicos iguana, Bartsch's iguana probably inhabits rocky coppice and sandy strand vegetation habitats (Iverson 1979). D. Blair reported that he saw one group of about ten goats on the eastern portion of the island in 1988. The vegetation was heavily grazed and stunted, and the area was littered with goat droppings. J. Bendon reported the presence of goats in 1997, but indicated that they did not appear to be impacting the habitat severely.
Threats
The immediate threat to the single population of Bartsch's iguana is the presence of goats, introduced to Booby Cay by the individual who holds the land under Crown lease. The cay is not readily accessible from the settlements on Mayaguana which could be the reason this population has survived so far. However, the cay is visited on an irregular basis by local conch fisherman, who sometimes overnight there. Catastrophe, particularly in the form of a hurricane or hurricane surge, is a very real threat.
Current conservation programs
All Bahamian rock iguanas are protected under the Wild Animals Protection Act of 1968. There have been no reports of poaching of iguanas on Booby Cay and it is not known if any are taken by local fishermen for consumption. The Bahamas National Trust has proposed to the Bahamas Government that Booby Cay, which is also of significant value for nesting seabirds, be named a protected area under the national parks system.
Representatives of the Wildlife Committee of the Bahamas National Trust and the Department of Agriculture began to survey the status of the iguanas on Booby Cay in early 1995 and to initiate removal of feral goats. There are no other research programs in progress or currently proposed for this subspecies, and no captive programs currently exist.
Critical conservation initiatives
- Removal of feral goats from Booby Cay. Prior to such action, the status of the Crown Lease will need to be reviewed and ownership of goats determined.
- Establishment of protected area status for Booby Cay.
- Institutional strengthening of responsible agencies to develop enforcement capabilities.
- Initiation of a national education program for tourists and residents.
Priority projects
- Assess the present status of the population on Booby Cay, identify plant species cay wide, and monitor vegetation changes after removal of goats.
- Determine whether any subpopulations exist at the eastern end of Mayaguana and establish captive breeding programs with the potential goal of restocking on Mayaguana.
Contact persons
Sandra Buckner
Bahamas National Trust
PO Box N4105
Nassau, The Bahamas
Tel: (242) 393-3821
Fax: (242) 393-3822
E-mail: sbuckner@bahamas.net.bs
David Blair
Cyclura Research Center
PMB #510, 970 West Valley Parkway
Escondido, CA 92025 USA
Tel: (760) 746-5422
Fax: (760) 746-1732
E-mail: critter@herpnut.com
