Rodent eradication on Molara Island and surrounding islets (NE Sardinia): from success to the riddle of reinvasion.
The eradication of rodents in islands, aimed at conserving seabird populations and other components of insular ecosystems, is becoming a common management practice. To restore island ecosystems, rodents, mainly rats (Rattus spp.) and house mouse (Mus musculus), are removed according to standardized methods. These methods include the helicopter delivery of poisoned baits which has allowed access to larger islands (up to more than 12 000 ha) or those that are difficult to access. In recent years, eradication projects have been carried out in the Mediterranean Sea, on small- to medium-sized islands. The largest of these, where success has been confirmed, are Lavezzi (73 ha), Zannone (103 ha) and Giannutri (240 ha), which have been all treated by networks of bait stations placed on the ground. High predation rates by black rats (Rattus rattus) on the largest population of Yelkouan shearwater (Puffinus yelkouan) suggested the urgent adoption of conservation measures in the Tavolara archipelago (NE Sardinia), within the Tavolara-Punta Coda Cavallo Marine Protected Area. An action plan for an overall decrease of the rat impact has been produced, and operational strategies have been evaluated for all different islands and islets of this area.