Abstract

Most oceanic islands in the world have been invaded by rats, which have negative effects on the local biota. A number of studies have reported rat predation on amphibians, but there is scarce information on the relations of trophic interactions present in these cases (competition, origin of energy production sources, trophic levels). Using diet data and stable isotopes, we explored the trophic interactions of the Isla Mocha in southern Chile, in particular between Rattus rattus (Black rat, invasive) and Eupsophus insularis (Mocha Island ground frog, endemic). The results show an important overlap in the prey used by both species, in the trophic positions they occupy, in their isotope niches and the presence of isotopic signals attributable to the anurans in tissue samples of rats. Understanding the trophic relations between invaders and native species is an important challenge for the implementation of conservation plans.