Valuation of water purification ecosystem services: a comparative study between wetlands and other natural and anthropic systems in the South of Brazil
Valuation of water purification ecosystem services: a comparative study between wetlands and others natural and anthropic systems in Southern Brazil
DOI:
https://doi.org/10.5016/geociencias.v42i2.17786Abstract
Wetlands are ecosystems with a great capacity for nutrient retention, offering a valuable ecosystem service for improving water quality. In this sense, the present article aims to quantify this ecosystem service and the economic value associated with it in the fresh and salt marshes of the Patos Lagoon Estuary, compared to other environmental systems. To do so, models from the InVEST platform were used to calculate surface water runoff, nutrient loading, export, and retention, such as total nitrogen - NTK and total phosphorus - PT. The economic valuation of the nutrient retention ecosystem service was made using the avoided cost of sewage treatment for nutrient removal as a parameter. The results showed that the real use flow of the ecosystem service of nutrient retention is determined by the demand for the service and that, therefore, anthropic environmental systems such as agriculture and livestock obtained higher values of retention since they are the systems that contribute the most nutrients to the Patos Lagoon Estuary. It was also observed that the retention capacity of a basin has a greater relationship with the spatial distribution pattern of the environmental systems along this basin, i.e., its hydrology, than with their own retention capacity. The fresh and salt marshes of the Patos Lagoon Estuary, when combined, have an economic generating capacity that can reach up to R$ 212,851,581.06 per year. The avoided cost-based valuation proved to be a viable methodology, given its simplified operation and input data accuracy. Considering the limitations of the model regarding data acquisition, it was concluded that the present study brings important information to decision-makers, but the results should be understood as preliminary and used with caution.
