AIMS: This study aimed to assess the impacts of anthropic activities at four sites of two rivers from the Mogi-Guaçu watershed in São Paulo State, Brazil; METHODS: Sites were classified according to their environmental integrity, based on the index developed by Callisto et al. (2002). Physico-chemical and biotic metrics were measured bimonthly. Principal Component Analysis (PCA) analysis was used to assess the relationship between sites and samples. Measures of soil loss evaluated the impacts from land uses at the Mogi-Guaçu watershed; RESULTS: Fifty-two macroinvertebrate families were identified at Oriçanga and Itupeva rivers. The Calamoceratidae (Trichoptera) are shredders, and their percentage was greatest at the most preserved site, where the riparian forest was in good condition. Some unexpected results were found at (ORIC 1), considered a minimally disturbed site according to a Rapid Assessment Protocol. At this site, family richness and Shannon-Weaver diversity index were both low, which could be attributed to riparian forest deforestation, resulting in less aquatic biodiversity. Principal Component Analysis (PCA) showed differences in physico-chemical parameters and macroinvertebrate families, but these differences were not so evident to separate sites according to their environmental integrity degree; CONCLUSIONS: We conclude that water quality seemed to be related to land use, as soil losses prevailed in pasture and sugar cane areas, where water quality parameters (biotic and physico-chemical) showed worse results. And that land uses must consider the slope of areas near aquatic ecosystems, due to the potential environmental impacts to these systems, especially erosion and inflow of polluted effluents.
biomonitoring; water quality; Mogi-Guaçu watershed; soil loss
