Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Late stage dynamics of a successful feral goat eradication from the UNESCO World Heritage site of Aldabra Atoll, Seychelles.

Abstract

Feral goats Capra hircus, considered among the world's most destructive invasive mammals, were introduced to Aldabra Atoll, a UNESCO World Heritage site in the Seychelles, before 1878. An eradication programme to remove goats from Aldabra was initiated in 1987, after severe ecological impacts were recorded. Eradication and control efforts continued intermittently for the next 20 years, and a final campaign was launched in 2007 using the Judas goat method. We present the methods, eradication dynamics, outcomes and financial costs of the final eradication campaign between 2007 and 2012. This effort was divided into three phases; (1) establishment of Judas goats and intensive hunting (4 months); (2) monitoring of Judas goats (4 years); and (3) Judas goat elimination and verification of success (8 months). In the focal 5-year period, 227 goats were culled (of 2297 across the entire 25-year period); 202 in phase 1, 21 in phase 2, and four remaining Judas goats in phase 3. The eradication was completed and confirmed successful in August 2012, following the use of multiple measures to confirm the absence of goats. The total cost of the eradication was US$ 185,105, an average of US$ 815/goat, or US$ 31/ha. The eradication, although ultimately successful, posed a unique combination of challenges. We discuss key lessons learned and put the project in context of other major island goat eradications. The financial details, context and lessons are expected to be of value to future practitioners.