Community structure of medium-large mammals across a tree plantation cycle in natural grasslands of Uruguay

Abstract

In temperate South America, the conversion of natural grasslands into crops and exotic tree plantations, such as with Eucalyptus sp., has reached outstanding levels, especially in the Río de la Plata Grasslands. The cycle of Eucalyptus plantations for pulp production is a very dynamic phenomenon; however, most of the studies on the impacts on biodiversity have been static and focused on the mature stage of the plantation. We studied the mammal assemblage in a grassland afforestation landscape of Uruguay to address how mammals respond to habitat complexity variation across the plantation cycle and landscape characteristics. We installed 26 camera traps for two years in four different age stages of Eucalyptus plantations and native habitats to assess mammals’ richness, composition, and intensity of habitat use. We registered 16 mammal species, 13 native and three exotics, with a sampling effort of 19,136 camera-nights. Of these species, 11 were found in the Eucalyptus plantations but with significant variability during the production cycle. Only one species was recorded at the beginning (0–2 years) of the cycle and four species at the end (8–10 years). But at intermediate ages (2–4 years), when vegetation complexity resembles a native forest structure, species richness was maximum (11 species) in the plantations and relatively close to forest richness (14 species). Species composition was also determined by habitat structure, but it was further modulated by landscape features, particularly the proximity to native forests and landscape heterogeneity. Our results demonstrated that asynchronous plantations promote spatial heterogeneity that favors mammal diversity in afforested landscapes, but for grassland mammals, additional conservation management measures are needed.