Rockin’ Rock Iguana Recovery Program
The Lesser Antillean Iguana occupies less than 10 main islands of the northern Lesser Antilles. Historically, the iguanas were common on almost every island from Anguilla in the north to Martinique in the south. Habitat degradation, non-native predators and competitors, hunting, road mortality, and genetic introgression (e.g. interbreeding) with common green iguanas threaten Lesser Antillean iguanas with extinction across their range. The Commonwealth of Dominica is believed to support the largest, single population of this species because of its expansive, undisturbed coastal habitat. This population provides the opportunity to study the species under natural conditions prior to catastrophic declines and subsequent cascading demographic perturbations occurring elsewhere in the Lesser Antilles.
This study focuses on investigating life-history variation between disturbed and undisturbed iguana populations. Study variables include clutch size, age to reproduction, nest-site selection, hatch rate, and juvenile and adult survival. In addition to investigating life histories, we will radio-track adult females migrating away from nesting sites to better understand habitat use requirements. Working with coastal populations on Dominica provides a means to close the gap in connecting different landscapes using charismatic species as conservation flagships. Currently, parrots are seen as a flagship for inland mesic forests, while sea turtles represent beach habitat. However, mid-elevation scrub areas lack such a focal species and iguanas have charisma and conservation appeal. We have been working with the Education Department in the Dominica Forestry Division to visit primary schools and speak about iguanas, printed and distributed over 300 educational iguana bumper stickers, appeared on national television and radio call-in shows, and other public relations opportunities.
Bahamian iguanas inhabit the islands of Andros and the Exuma Cays. They face unique pressures relative to other islands in the archipelago such as habitat loss, intense illegal poaching, and impacts from historic large-scale logging practices for Caribbean pine. In contrast, the islands in the Exuma chain are relatively small and relatively uninhabited by Bahamians. However, the Exuma iguana subspecies is fragmented with individuals inhabiting fewer than 13 islands. Escalating human presence in the area increases the chance of non-native wildlife and plant introductions on private and subsequently iguana-inhabited islands. Additionally, thousands of yachtsmen and tourists visit the islands each year and disrupt iguana population with constant food supplementation.
Our Bahamian project involves conducing scientific research in both the Exumas and on Andros in order to provide the Bahamian government with recommendations for conservation management. The work includes conducting ecological assessments of islands to be included as potential national parks, performing long-term mark/recapture and monitoring research to document population stability, conducting studies to determine the effects of food provisioning, and translocating iguana colonies at the request of the Bahamian Department of Agriculture. We have erected signs on the small Exuma Islands that advertise the protective status of the iguanas. We have formed partnerships and are also involved with conservation education on Andros Island, including teacher workshops.
The Anegada iguana is the largest native terrestrial vertebrate and dominant herbivore of the British Virgin Islands. With fewer than 400 individuals remaining, the Anegada iguana is one of the rarest lizards in the world. Threats include land clearing that destroys habitat, feral livestock that trample nest sites and severely over-browse the vegetation iguanas rely on for food, and feral cats that kill nearly all hatchlings each year. The Anegada iguana project is a long-term program involving a combination of applied ecological research, public education and awareness, local capacity building, and population enhancement through headstarting. We have directly supported these activities since 1997. Our field research and associated headstarting and release efforts are continuing. In addition to annually locating and protecting nests, collecting hatchlings for headstarting, and releasing headstarted animals, current field efforts are focused on mapping all active iguana retreats and conducting a mark-recapture study focusing on these retreats. Long-term survival of the Anegada iguana will ultimately depend upon its habitat being protected and feral mammals being removed.
Our experience and success with these projects is being used to develop and guide other iguana projects, such as those now being undertaken by our Conservation and Research Postdoctoral Fellow for Lesser Antillean and Northern Bahamian iguanas. In addition, thanks to generous donors, a 2,000-square-foot, off-exhibit breeding facility for three Caribbean rock iguana species has opened at the San Diego Zoo’s Wild Animal Park: the Kenneth C. and Anne D. Griffin Reptile Conservation Center. It is the first facility in the world fully dedicated to rock iguana reproduction. We appreciate the support of our goal to secure the long-term survival of Caribbean iguana species and their threatened dry-forest ecosystems.
