Conservation, Research and Education Opportunities International

Estimating effects of eradication of European rabbits (Oryctolagus cuniculus) on native and endemic plant communities, and on breeding density of Peruvian diving-petrels on Choros Island, Coquimbo, Chile

C. Fernández Zamora

The Peruvian diving-petrel Pelecanoides garnotii (endangered) was once very common on the coastal islands off Peru and Chile. However, the extraction of guano and introduction of species on islands has decreased its populations throughout its former range. Today, the largest population of diving-petrels in Chile is located on Choros Island, which is also characterized by a high diversity of native and endemic flora. Choros Island, however, has been subject to the introduction of exotic species, including European rabbits Oryctolagus cuniculus. Rabbits are known to destroy breeding-burrows of petrels while constructing dens. Rabbit foraging has reduced plant cover, leaving exposed soil and increasing soil erosion/burrow collapse. From November 2010 to the present, with help of CREOi funds, we have been monitoring breeding density of diving-petrels, and cover of plants throughout random sampling points distributed on the island. During 2013, European rabbits were eradicated from Choros Island, providing an opportunity to analyze the effect of eradication on the island. Given this opportunity, we propose to analyze in a whole-ecosystem context the effects of eradication on breeding density, physiological condition and reproductive success of Peruvian diving-petrels, and the impact of eradication on native and endemic plants on Choros Island. ($8,000)