Evaluating the impacts and conservation value of exotic and native tree afforestation in Cerrado grasslands using dung beetles

Abstract

1. Although plantation forests are being established at an increasing rate, their effects on biodiversity are still debated.

2. Native candeias [Eremanthus erythropappus (DC.) Mac Leish] and exotic eucalyptus (Eucalyptus spp.) have recently been planted on Cerrado grasslands. The Cerrado is the second largest biome of Brazil and one of the most threatened savanna ecosystems.

3. Here, we use dung beetles (Scarabaeinae) to investigate the effects of the land‐use changes associated to afforestation on Cerrado insect biodiversity. We sampled dung beetles in candeia (4‐ and 6‐year‐old) and eucalyptus plantations (1‐ and 4‐year‐old), natural candeia formations (candeiais), native grasslands and natural forests.

4. Dung beetle diversity in plantations was lower than in grasslands and forests, but was not different from diversity in natural candeiais. Candeia and 1‐year‐old eucalyptus plantations, grasslands and natural candeiais all had similar community composition, distinct from natural forests. Four‐year‐old eucalyptus plantations were intermediate between those two groups. Overall, afforestation was detrimental for dung beetles.

5. Differences between exotic and native plantations were only apparent in older plantations, and seemed to be due to differences associated to canopy openness rather than to the origin of the planted species. Candeia plantations were of better conservation value for open‐area species (62% species shared between grasslands and candeia plantation) whereas eucalyptus plantations were so for forest species (26% species shared between forests and eucalyptus plantations). We recommend considering this result before deciding where to plant which species.