Limnetica 40
Do tropical riparian forests in the Cerrado Biome act as a buffer against the impacts of agriculture and livestock on benthic macroinvertebrate communities?
Studies on aquatic ecosystems evaluating the effects of land use on benthic macroinvertebrates communities indicate that predictive biological metrics of good environmental quality, such as taxonomic richness and diversity, are lower in streams located in agriculture and livestock areas without a forest buffer when compared to areas of natural vegetation. To test the hypothesis that the structure of benthic macroinvertebrate communities of streams located in impacted areas could be similar to those in intact areas if the riparian vegetation is preserved, we sampled five streams in natural vegetation areas, five in agriculture areas, and three in pasture areas. For the last two stream categories, only locals with preserved riparian vegetation following the Brazilian Forest Code (minimum width of 30-m from each margin) were selected. Land use adjacent to the riparian vegetation was evaluated through satellite images at an 150 m radius around the upstream limit of each stream. The richness of taxa (families or orders), estimated by rarefaction based on the smallest sample of 7826 individuals, was similar (49-53 taxa) in the three categories of streams, that also did not differ in the community metrics (Simpson Index, Shannon-Winner Diversity Index, % Chironomidae, Evenness, Richness, and % EPT) and in the proportion of functional trophic groups. Moreover, the composition of benthic macroinvertebrate communities was also similar among stream categories. These results indicate that the preserved riparian vegetation minimizes the impacts of agricultural and livestock activities on the benthic macroinvertebrate communities in Cerrado biome.
