Invasive Species Compendium

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Abstract

Foraging ecology of introduced rodents in the threatened Macaronesian laurel forest of São Miguel Island (Azores) and contiguous exotic forests.

Abstract

On São Miguel Island, Azores (Portugal), introduced rodents may constrain conservation efforts being taken on the Macaronesian laurel forest. With the aim of assessing their foraging ecology in one of the last patches of native laurel forest, we carried out snap-trapping sessions to evaluate rodent relative abundance and diet in three habitats (exotic forest, forest plantation, and forest opening) during winter, spring, and summer. Two species (Rattus rattus and Mus musculus) were captured, and capture rates were higher in winter, particularly in native laurel forest, followed by a decrease in all habitats, with the exception of forest plantation. Stomach contents' analysis showed that invertebrates, mainly Annelida and Arthropoda, made up the greatest part of both species' diet in the four habitats, but there was an important component of plant consumption, with a large bulk corresponding to the exotics Cryptomeria japonica and Hedychium gardnerianum. Our results show that temporal variations on the relative abundance and diet of these rodents were more significant than habitat variations.