Battling Extinction

A View Forward for the Grand Cayman Blue Iguana (Cyclura lewisi)

Abstract

The National Trust for the Cayman Islands has been implementing conservation efforts for Cyclura lewisi since 1990. Commencing with small-scale captive breeding, the program has expanded to include field research, large-scale captive breeding and head-starting, reintroduction and restocking, habitat protection and management, education, and awareness activities. A formal species recovery plan is in place. In the past 12 years, the size of the wild population appears to have declined from 100–200 to 10–25 animals and is functionally extinct. Principal causes for the decline are habitat loss, predation by introduced mammals, road kills, and continued exploitation by humans. Reproduction in the wild by animals released from the captive breeding population has been confirmed. However, in order to assure the greatest possible genetic diversity within the captive population, wild individuals with potentially distinct genetic constitutions must be captured and assessed before their genes become diluted as a consequence of interbreeding with released animals. Goals of 100 hatchlings and approximately 100 two-year-old iguanas for release annually are being approached. Options for restoring self-sustaining wild populations are limited to habitat islands, for which perimeter fencing will be essential to restrain iguanas and exclude predators. The recovery program is operating on institutional grants, program-generated income, and private donations, but we hope that this charismatic lizard will become able to support its own survival through carefully managed tourism activities and related commerce.