Homogenization of diatom assemblages is driven by eutrophication in tropical reservoirs.

Eutrophication is one of the most widespread causes of biotic homogenization in freshwater ecosystems. Biotic homogenization can be characterized as reductions in local diversity (alpha) and occupation of available niches by more generalist species. Beta diversity is expected to decrease in more homogeneous communities, however, there is no consensus on how it responds to eutrophication.

Structure and species composition of diatom community during the wet season in three floodplain lakes of Brazilian Pantanal.

In order to access environmental conditions, the use of bioindicators that have a close relationship with environmental stressors is a largely common practice, but when evaluating environmental inferences, the individual dominant taxa need to be interpreted. Humid regions such as the marshlands are fragile ecosystems and sustain communities of microalgae, often used as bioindicators, of which diatoms are a good example. Although they provide an excellent response to chemical and physical changes in water, diatom studies in surface sediments in wetlands are scarce worldwide.

Effects of land use and spatial processes in water and surface sediment of tropical reservoirs at local and regional scales.

The effects of land use and connectivity on the characteristics of aquatic ecosystems are thought to be scale-dependent. This study aimed to evaluate the relationships between land use and reservoir characteristics at two spatial scales, after controlling for spatial processes. Water and surface sediment samples were collected from 31 sites (7 reservoirs) in the Paiva Castro and Piracicaba River basins (Cantareira System, São Paulo State, Brazil), during austral summer and winter.