Ecosystem-based spatial modeling: Assessing the supply of hydrological services in a watershed in Southern Brazil

Hydrologic services describe the way terrestrial ecosystems affect freshwater resources. This study employed an ecosystem-based approach and spatial models to assess the significance of ecosystems in providing hydrological services in a Watershed in southern Brazil. The environmental systems and hydrological services were characterized and evaluated for the significance weights assignment by expert opinion dynamics. Spatial and tabular data generated were applied in an ecosystem services model (InVEST-Integrated Valuation of Ecosystem Services and Trade-offs) for a relative importance analysis. Map algebra was performed to integrate relative importance with runoff values, resulting in an importance index (II), which enabled the identification of the most important ecosystems for the hydrological services provision. Among the environmental systems, riparian forests (0.2457), forests (0.2455), wetlands (0.2332), and fields with livestock (0.2291) demonstrated the highest II values. Ranking environmental systems and their vegetation cover based on their performance in terms of ecohydrological functions and hydrological services has the potential to support management actions on land use in the pursue of sustainability regarding water resources use.