Grassland afforestation in South America: Local scale impacts of eucalyptus plantations on Uruguayan mammals

•Mammals’ assemblage was studied in five grassland afforested landscapes.•Substitution of grasslands for tree plantations generates a negative local impact.•Native and specialist species are the most sensible species to afforestation.•The generalist, omnivore, and insectivore species were the dominant groups.•Firebreaks could be key features as linear corridors connecting native vegetation.