Not only exotic grasslands: The scattered trees in cultivated pastures of the Brazilian Cerrado

Abstract

Cultivated pastures occupy 30% of the Brazilian Cerrado. Most pastures have low productivity, demanding intensification. Pasture intensification, as conventionally proposed, promises conservation by land sparing. However, it does not embrace silvopastoral systems, a type of intensification that enhances carbon balance and in situ biodiversity conservation. In the Cerrado, silvopastoral systems would be easily established because pastures with native trees are commonly found in the landscape. In this study, we estimated the density of scattered trees using RapidEye satellite data in 200 cultivated pastures (48,519 ha). We also identified tree species by establishing 93 field plots distributed along 15 ecoregions in the Cerrado biome. We expected that the density of trees would vary in function of farm size, age of the pasture, intensification of pasture management and biophysical variables. Mean scattered tree density was 3.52 tree ha-1 (? 2.93 SD), and it was higher in ecoregions with lower and more concentrated rainfall. The most frequent tree species were those with high commercial values, such as the Myracrodruon urundeuva timber tree (aroeira) and the Caryocar brasiliense fruit tree (pequi). The average above-ground carbon stock of native Cerrado trees in pastures was estimated in 1.2 Mg ha-1 (? 1.2 SD). Our study shows that there are productive pastures with high tree density and species richness, which could be used as models for sustainable intensification strategies in different ecoregions of the Cerrado.