LBA–ESECAFLOR Artificially Induced Drought in Caxiuanã Reserve, Eastern Amazonia: Soil Properties and Litter Spider Fauna

Abstract

A review is presented of soil properties and litter fauna of an experimental site in the Caxiuan? forest, eastern Amazonia, as a contribution to the Large-Scale Biosphere?Atmosphere Experiment in Amazonia (LBA). This study?s main scientific goal is to compare some biogeochemical soil properties of an undisturbed forest ecosystem with those of an experimental (1 ha) plot in which rainfall was artificially excluded to simulate drought [the Efeitos da Seca da Floresta (ESECAFLOR) experiment]. A second scientific objective is to investigate the space variability of soil profile characteristics in the experimental sites, particularly organic carbon concentration, moisture, and texture. It is expected that such soil property variability influences greatly the distribution of several biological species such as spiders. To investigate such effects in the litter spider community, we applied percentual complementarity and Simpson diversity index to available data. Our results suggest that a faunal transition was under way in the treatment plot, shifting from a rich and even community to a less diverse one.