Effects of forest fragmentation on community patterns of social wasps (Hymenoptera: Vespidae) in Central Amazon

Abstract

Landscape fragmentation is one of the greatest threats to environments globally, affecting all living organisms within fragments at many assembly levels. Despite such general assumptions, very few reports exist on the diversity patterns of Amazonian social wasps (Polistinae) in response to fragmentation. Our study aims at addressing how the community patterns of social wasp change from continuous to fragmented landscapes in the Amazon rainforest. We collected social wasps for a year (11 520 trap-hour effort) in a continuous forest and a highly disturbed urban forest fragment, located in Manaus, Brazil. We attracted wasps using sardine and orange juice traps, placed in 20 sampling plots. We collected 2742 wasps from 29 species. Agelaia pallipes, Angiopolybia pallens and Agelaia fulvofasciata were the most abundant species. We detected significant differences in overall abundance, species richness and species composition of social wasps between landscapes. Conversely, no difference in species diversity (effective number of species) was found between habitats. Despite the low quantity of exclusive species, the numbers of most species declined sharply in the fragmented habitat, while for one species (Polybia rejecta), abundance increased. Regarding the percentile of species contribution to dissimilarity between landscapes, five out of the first six species were highly abundant (>100 individuals), thus demonstrating that the observed pattern was very likely driven by common species. Additionally, our findings highlight that fragmentation threatens abundant species as much as rare species. We hope that our results encourage the use of social wasps as models in basic and applied ecological surveys and further efforts for conservation of pristine forest areas in the tropical region of South America. © 2018 Australian Entomological Society