From December 2003 to September 2004, benthic macroinvertebrates (BM), fishes, water and sediment were collected quarterly at six stations in two streams of the upper São Francisco River basin, south-eastern Brazil. We evaluated the ecological conditions, habitat diversity, water quality, composition and structure of BM communities, as well as the food habits of the local fish fauna. By applying a protocol for rapid characterization of ecological conditions and habitat diversity, three of the sampled localities were classified as "pristine" while the others stations were considered "altered". A well oxygenated water with near neutral pH and low electric conductivity (< 0.01 mS/cm) and nutrient concentrations (< 0.08 mg/l total P and < 0.90 mg/l... |