AIM: The aim of this paper was to study the spatial distribution and functional feeding structure of aquatic insect communities of 18 streams at different altitudes in Mambucaba River Basin, Serra da Bocaina, Southeastern Brazil; METHODS: Samples were collected in two consecutive dry periods (August of 2003 and 2004) being sampled four substrate types in each stream: litter from riffles, litter from pools, rocks and gravel; RESULTS: We identified 75,581 aquatic insect individuals belonging to 201 taxa. Most of the fauna was found in litter substrates (64%), and riffle litter substrate had the majority of the specimens (32,572 individuals). Gravel was the substrate with highest values of richness (29.84 taxa expected for 187 individuals; rarefaction method) and Shannon's diversity (H' = 2.370). Rock substrate showed the lowest richness (20.24 taxa). Distribution of taxa across substrates shows that only 28 taxa are restricted to a single substrate, while 78 taxa occurred in all substrates. The indicator analysis showed that 20 taxa were characteristic of pool litter, 25 of riffle litter, 22 of gravel and only nine to rock. In relation to organic and inorganic substrates, 29 taxa were characteristic of litter, and 17 of inorganic substrates. Cluster analysis based on Bray-Curtis dissimilarity index and UPGMA linkage method showed that aquatic insects were distributed according to substrate and food resource. In all substrates, the main functional feeding group was collector-gatherer (40.64%), and the least representative was shredder (6.67%). ANOVA and Tukey HSD tests showed that collector-gatherers and shredders were predominant in pool substrates, collector-filters in riffle substrate and scrapers in hard substrates; CONCLUSION: Ours results show that independently of stream or altitude, substrate of the same type have similar faunal assemblages. The abundance and relative proportion of the functional feeding group showed variation across habitats.
distribution; habitats; substrates; benthic macroinvertebrates
