Negative effects of exotic pine invasion on macroinvertebrate communities in southern Brazil coastal ponds

Abstract

Exotic pine invasion influences native wetland assemblages by changing environmental conditions such as hydrological regime and physicochemical characteristics. The expansion of cultivated pine has been a concern in southern Brazil and its impacts on aquatic biodiversity are poorly known. We tested the hypotheses that: (1) pine invasion decreases aquatic macroinvertebrate richness and abundance, modifying composition and macroinvertebrate functional feeding groups in ponds; and (2) β-diversity between natural and pine ponds is determined mainly by species nestedness. Five ponds in native grassland and five in a pine-planted matrix were sampled seven times from 2007 to 2009. The pine ponds had reduced macroinvertebrate richness and abundance, and different taxa and functional feeding groups. Comparing ponds in natural and cultivated pine areas, β-diversity as determined by nestedness did not differ from the value resulting from the turnover. Reduction of surface in ponds in pine areas may be one of the main causes for the lower macroinvertebrate richness and abundance because many taxa do not have adaptations to tolerate or escape the dry phase. Our results suggest that pine invasion has a negative impact on macroinvertebrate structure in southern Brazil coastal ponds.