An applied ecological approach for the assessment of anthropogenic disturbances in urban wetlands and the contributor river

摘要

An applied ecological approach was used to assess the anthropogenic disturbances on the aquatic systems of the Sorocaba river and its wetlands in the Sorocaba-SP municipality (Southeastern Brazil). Two samplings of water, sediment, macroinvertebrates, and macrophytes were performed in 2017, during the rainy season (February) and dry season (June). Traditional limnological methods were applied to the biological material (macrophytes and macroinvertebrates) and limnological variables. In 2017, domestic wastewater and diffuse pollution were the main anthropogenic impacts on the aquatic ecosystems of the Sorocaba municipality. The used approach allowed the verification of the human disturbances on aquatic systems, sediment, biological communities, and landscape. We found that biochemical oxygen demand, thermotolerant coliforms, total phosphorus, dissolved oxygen, and turbidity are above reference concentrations from the Brazilian guideline CONAMA Resolution 357/ 05. Four macroinvertebrates orders (Diptera, Oligochaeta, Hirudinea, and Gastropoda) and three macrophytes species (Eichhornia crassipes, Salvinia auriculata and Pistia stratiotes) allowed inferring that Sorocaba river and associated wetlands suffer water quality loss due to organic pollution. The major land use classes were anthropogenic agricultural and non-agricultural (75.42%) disturbances, contributing to limnological alterations and low quality of riparian vegetation. Urban wetlands were similar (e.g. sediment properties, limnological variables, bioindicators) and differed from the contributor river, a situation probably related to the wetlands bimodal pulse. Considering the hydric network of tropical countries in the same geographic region, the similar dynamics of the water bodies, and the context of urbanization, the approach can be applied to assess the human disturbances in the region.