Climatic conditions drive the abundance and diversity of spiders community in an Atlantic Forest fragment

Abstract

Spiders are very sensitive to variations in abiotic conditions. Here, we evaluated to what extent the variation in monthly rainfall and mean temperature can affect spiders community attributes. To this aim, we conducted an inventory of spiders species in a mixed ombrophilous forest fragment, using three different methods (beating tray, nocturnal manual collection and pitfall traps) over July 2010 and June 2011. The influence of monthly rainfall and mean temperature in spiders richness and abundance were evaluated using linear mixed models. We sampled 5,416 spiders belonging to 142 morphospecies and 28 families. These values were higher than those found in other studies conducted in temperate regions, and similar to those values found in tropical regions. Monthly mean temperature positively affected abundance and richness of adults, and negatively affected the abudance of immature spiders. Monthly rainfaill was negatively related to abundance of immature individuals. Species composition also differed between the hottest and coldest months. Our study helps us to understand the role of climatic conditions on spiders communities, and highlights that even small variations in these conditions can directly affect richness, abundance and species composition of spiders.