Ecology of the Monte Desert small mammals in disturbed and undisturbed habitats

Changes in habitat structure produced by cattle ranching can affect desert rodent communities. The effect of this activity on small mammal species was studied in the central portion of the temperate Monte Desert of Argentina. A protected (Man and Biosphere Reserve of Ñacuñán) and a disturbed area were compared, considering the heterogeneous mosaic of patches present in both areas. Depending on patch complexity, the response of species varied among patches and treatments (disturbed and undisturbed areas), some disturbed patches showing higher diversity than undisturbed ones. Species associated with habitats with dense plant cover, such as the grass mouse, Akodon molinae, were more abundant in the Reserve, whereas the silky mouse, Eligmodontia typus, associated with open habitats, was favored by the simplification of disturbed areas. Both the degree of patch complexity and the morphoecological attributes of species were good predictors of their presence in every patch. The selective use that domestic herbivores make of some areas may favor the maintenance of patches that are conducive to the occurrence of some species in disturbed areas.