Effects of urbanization on habitat characteristics: what are the responses of habitat alteration on functional feeding groups of aquatic invertebrates?

Urbanization causes many changes in stream communities and rivers usually suffer major structural modifications under intense urban occupation. The goal of this study was to investigate the effects of urbanization on physicochemical habitat characteristics and evaluate the responses of urbanization on functional feeding groups (FFGs) of invertebrates. Water quality parameters (temperature, conductivity, dissolved oxygen, pH, phosphorus, chlorophyll-a, turbidity and organic matter) and flow parameters were measured in least and severely urbanized areas. FFGs of macroinvertebrates were analyzed and applied as surrogates of ecosystem attributes. The differences in the macroinvertebrate community of the least and severely urbanized areas were assessed using non-metric multidimensional scaling (nMDS) and a permutational multivariate analysis of variance (Permanova). Differences between the least and severely urbanized areas were observed with nMDS. The Permanova also showed a significant difference between the nMDS groups. The least urbanized areas presented greater richness for each FFG. On the other hand, severely urbanized areas presented a major abundance of gathering collectors and predators. Thus, the composition of FFGs responded to habitat alterations that were represented by water quality and the flow parameters.