Short-term effects of reduced-impact logging on eastern Amazon fauna

In Amazonia, the effect of logging on fauna and the ability of reduced-impact logging (RIL) techniques to conserve the ecological integrity of forests is not well understood. In this study, we evaluated the short-term effect of RIL on species richness, abundance and composition of native Amazonian fauna (ants, arachnids, birds and mammals) 6 months after logging. We evaluated the response of fauna in pre- and post-logging treatments in 2–4 plots of 100 ha for each annual production area of three different sites in Para state, Brazil. Arthropods were sampled with pitfall traps in 2002, and diurnal birds and mammals were recorded using line transect methodology in 2002 and 2003. All groups were sampled between April and July, when there was no logging activity. We predicted that animal assemblages in RIL sites would be similar to the pre-logging sites as techniques were designed to minimize damages. In our study sites, logging intensity averaged 19 m3 ha−1. Overall, the effect of RIL on fauna was minor. The major changes were an increase in species richness of invertebrates and birds, confirming the expected pattern after recent disturbance. Mammals showed no changes in richness, abundance and composition. Arachnids were the only group showing responses in all three ecological variables. The low intensity of logging, and the connectivity with a matrix of logged and unlogged forests, may have promoted rapid recolonization at our study sites. The lower species loss in RIL forests compared to other types of land use in Amazonia highlights the value of this technique for conservation purposes among prominent economical activities.