Ligeiro, Raphael; Hughes, Robert M.; Kaufmann, Philip R.; Macedo, Diego R.; Firmiano, Kele R.; Ferreira, Wander R.; Oliveira, Déborah; Melo, Adriano S.; and Callisto, Marcos, "Defining quantitative stream disturbance gradients and the additive role of habitat variation to explain macroinvertebrate taxa richness" (2013 Currently, most rigorous methodologies designed to define those conditions are suited to large spatial extents (nations, ecoregions) and many sites (hundreds to thousands). The objective of this study was to describe a methodology to quantitatively define a disturbance gradient for 40 sites in each of two small southeastern Brazil river basins. The assessment of anthropogenic disturbance experienced by each site was based solely on measurements strictly related to the intensity and extent of anthropogenic pressures. We calculated two indices: one concerned site-scale pressures and the other catchment-scale pressures. We combined those two indices into a single integrated disturbance index (IDI) because disturbances operating at both scales affect stream biota. The local-and catchment-scale disturbance indices were weakly correlated in the two basins (r = 0.21 and 0.35) and both significantly (p < 0.05) reduced site EPT (insect orders Ephemeroptera, Plecoptera, Trichoptera) richness. The IDI also performed well in explaining EPT richness in the basin that presented the stronger disturbance gradient (R 2 = 0.39, p < 0.001). Natural habitat variability was assessed as a second source of variation in EPT richness. Stream size and microhabitats were the key habitat characteristics not related to disturbances that enhanced the explanation of EPT richness over that attributed to the IDI. In both basins the IDI plus habitat metrics together explained around 50% of EPT richness variation. In the basin with the weaker disturbance gradient, natural habitat explained more variation in EPT richness than did the IDI, a result that has implications for biomonitoring studies. We conclude that quantitatively defined disturbance gradients offer a reliable and comprehensive characterization of anthropogenic pressure that integrates data from different spatial scales.

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Aim: Changes in land use and cover (hereafter land use) affect freshwater ecosystems at different spatial scales. We tested the effects of land use on the dispersal capacity of stream macroinvertebrates through local and regional processes. Location: In all, 183 Brazilian headwater stream sites, located in the Neotropical Savanna with variable land use and covering a total area of 46,394 km 2. Taxon: Stream macroinvertebrates Methods: We used multiple regression models for distance matrices to identify the relative importance of environmental and landscape characteristics to explain community dissimilarity of stream macroinvertebrates with different mobility traits. As

This book is dedicated to the memory of our friend Volney Vono. We miss him, his funny stories, and his ecological knowledges.