Population size, income and poor sanitation interact to explain widespread streamwater contamination by antidepressants in the Metropolitan Region of São Paulo.

The expansion of urban settlements over native environments may expose biodiversity to a host of emerging contaminants, with unintended ecological effects. This study evaluated patterns of contamination of streamwater by antidepressants in the Upper Tietê River Basin, a watershed of high social, economic and environmental relevance for comprising both the largest urban settlement in South America (the Metropolitan Region of São Paulo) and remnants of a globally important biodiversity hotspot (the Atlantic Rainforest). We sampled 53 third-order streams draining catchments regularly distributed across a gradient in urban cover.

Parasite-Driven host manipulation: The case of trematodes in Neotropical tadpoles.

Parasites can impact tadpole survival in both lethal and sublethal ways. Sublethal effects include alterations in morphology and behavior, reduced competitive ability, and increased vulnerability to predation, while lethal effects result in direct mortality. These impacts can have significant consequences at both individual and population levels, especially given that amphibians host various parasites and pathogens, which may contribute to population declines.

Top predator introduction changes the effects of spatial isolation on freshwater community structure.

Current conceptual metacommunity models predict that the consequences of local selective pressures on community structure increase with spatial isolation when species favored by local conditions also have higher dispersal rates. This appears to be the case of freshwater insects in the presence of fish. The introduction of predatory fish can produce trophic cascades in freshwater habitats because fish tend to prey upon intermediate predatory taxa, such as predatory insects, indirectly benefiting herbivores and detritivores.