The effect of reduced-impact logging on fruit-feeding butterflies in Central Amazon, Brazil

Abstract

The Amazon region represents more than a half of all tropical forests in the world, and has been threatened by many anthropogenic activities, including several kinds of timber harvesting. The reduced-impact logging (RIL) is considered a less destructive method of timber harvesting, but there is a general lack of information about the effects on Amazonian invertebrates, including butterflies. We investigated the effect of RIL on fruit-feeding butterflies by comparing canopy and understory between an area under RIL and a control area without RIL. The canopy fauna is different and significantly richer than the understory fauna, showing that sampling only the lower strata underestimates the diversity of fruit-feeding butterflies. The effects of RIL were mainly detected in the understory butterfly assemblage, as significant differences were observed in species composition within this stratum. Effects of the RIL regime, which include tree cutting, skid trails and roads openings, are stronger in the understory than in the canopy, explaining the reported differences. Despite the detectable effects of RIL on the composition of fruit-feeding butterfly assemblages, the overall diversity was not affected. A similar pattern has been detected in many other groups, indicating that a noticeable part of the diversity of many taxa could be preserved in areas under RIL management. Therefore, in view of the problems of creating protected areas in the Amazon, RIL is a good alternative to preserve fruit-feeding butterflies and surely many other taxa, and it might be a desirable economic alternative for the region.