Rodent eradication on Molara Island and surrounding islets (NE Sardinia): from success to the riddle of reinvasion

The eradication of rodents on islands, aimed at the conservation of 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, including the helicopter delivery of poisoned baits, which has allowed access to larger islands (up to more than 12,000 ha) or difficult to access islands (Howald et al 2007, Veitch et al., 2011). In recent years eradication projects have been carried out in the Mediterranean Sea (Genovesi & Carnevali, 2011), on small to medium sized islands: the largest of these where success has been confirmed are Lavezzi (73 ha, Pascal et al. 2008), Zannone (103 ha, Francescato et al. 2010) and Giannutri (240 ha, Sposimo et al. 2008), 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 (Baccetti et al. 2009; Zenatello et al. in press.) (Fig. 1), 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 was produced and operational strategies were evaluated for all different islands and islets of this area.