Diversidade, padrões de distribuição e esforço de coleta de borboletas frugívoras em floresta ombrófila densa da Amazônia, Manaus, Brasil

Abstract

Spatial and temporal ecological patterns of the organisms are essential biological data for decision involving conservation politics and land management. Plenty of groups have been used as models to generate such patterns for being considered as bioindicators. Among them, there are the butterflies. In particular, fruit-feeding butterflies are very popular insects, due to their facility in sampling and identification. However, even though the use of traps allows a simultaneous and standardized sampling, part of the sampling design do not seem to have reached a consensus among studies: the sampling period. In this light, each of the two following chapters addresses a different question: (1) which environmental factors influence the spatial distribution of fruit-feeding butterflies? and (2) based on sampling schemes, what is the sufficient sampling period to capture biological information about fruit-feeding butterfly community? The study was carried in Reserva Ducke, Manaus, Amazonas from June to August 2013 and butterflies were collected using both hand net and bait traps. Relationships with environmental variables were investigated by running multiples regressions between the first ordination axis of the butterfly species composition and four potential predictors: vegetation species composition, dry litter mass, litter phosphorus content and terrain slope. Sampling sufficiency was assessed by Mantel tests, when we compared species composition similarity between the maximum effort (four-visit scheme) and the reduced efforts (three-, two- and one-visit schemes). We also ran multiple regressions in order to test whether the reduced efforts could reflect the ecological patterns observed in the maximum one. We collected 401 butterflies belonging to 41 species. The best set of predictors showed by multiple regressions was the combination of vegetation species composition and dry litter mass. These two variables and terrain slope determined the spatial distribution of fruit-feeding butterflies based on body size. According to Mantel tests, the three-visit scheme is enough to capture similar species composition e still reflect the ecological patterns found with the four-visit scheme. In the event the project does not demand a full taxonomic list, even the two-visit scheme is viable. It was also exposed that the removal of unique species does not affect the ecological response of the community, since the patterns are being driven by the common species. The associations between butterflies and the environment show how populations react against habitat change. In addition, the reduction in sampling effort enables project resources to be used more efficiently. Both conclusions head to a common goal: to support biodiversity conservation.