Changes in functional diversity of aquatic invertebrates across urbanization levels in a coastal island, Brazil

As the world becomes more urbanized, multiple stressors act in complex ways, but their effects remain poorly studied in coastal island streams. Due to the small length and isolation and the limited amount of freshwater available in the islands, these ecosystems are particularly vulnerable to anthropogenic pressures. Here, we investigated the effects of urbanization on taxonomic and functional diversity of aquatic invertebrate of a subtropical coastal island. Benthic invertebrate communities were sampled using litter bags (10 mm mesh) containing mixtures of leaf litter that were colonized in the stream bottom over 30 days. We hypothesized that invertebrate communities would show alteration in taxonomic and functional composition over the urbanization gradient. Based on the invertebrate communities and their biological traits, we computed the taxonomic richness and four functional diversity indices. Significant changes in taxonomic, functional richness, evenness, and dispersion were observed. Sites with low urbanization (< 5