Effects of multiple stressors associated to land use practices in the Percy-Corintos basin (Northwest Chubut): an ecological assessment

Abstract

Freshwater ecosystems are highly interactive with the processes that occur in the surrounding basin. Any alteration of either aquatic or terrestrial ecosystems can potentially impact the structure, composition and functioning of aquatic communities. The Percy-Corintos Basin (northwestern Chubut Province) is subjected to multiple land-uses including urbanization, deforestation, extensive and intensive livestock breeding, pasture conversion, and horticulture. These local processes have had profound effects on a regional scale, altering the water quality and biodiversity of the main watercourses and associated wetlands. Livestock breeding and wood collection have resulted in an important loss of forest cover in the upper Percy basin, which has in turn accelerated erosion processes, causing sedimentation at the lower section of the basin. Urbanization has resulted in strong organic pollution, habitat impoverishment, and has decreased macroinvertebrate biodiversity in Esquel Stream. In pre-urban areas, constructed wetlands for flood prevention, act as novel environments which increase spatial heterogeneity, and consequently enhance macrophyte and aquatic invertebrate diversity. While urbanization in the lower Percy basin has a moderate effect on the river, agricultural activities like confined livestock breeding and horticulture are increasingly affecting the environmental and biological quality of the Corintos River. Management and restoration actions are urgently needed in order to restore the ecosystem functioning. The present study details and discusses specific actions to conserve biodiversity and ecosystem services.