Quantifying, Modelling and Mapping Ecosystem Services in Watersheds

Abstract

Quantifying, modelling and mapping ecosystem services is an important step to the application of ecosystem services in practice and decision making. Watersheds are functional entities that provide an appropriate spatial scale for water flow analysis and integrate all the processes that occur within their boundaries. Multiple ecosystem functions occur within watersheds, providing water-related ecosystem services such as freshwater provision, groundwater recharge, water purification and flood regulation. A matrix approach was applied, linking different land cover types within watersheds to different ecosystem functions and services. Supply capacities of different land cover types and respective changes over time were assessed. By applying the watershed-based hydrologic model KINEROS and the GIS based AGWA tool, water retention functions of different land cover classes in the Bulgarian case study areas Malki Iskar, Vidima and Yantra were assessed. Based on the modelling results, flood regulating ecosystem service supply capacities were quantified and mapped in the three watersheds. A digital elevation model, land cover information and accessibility data were used to compile maps of demands for flood regulating ecosystem services. Supply-demand budgets were calculated and mapped for the study areas using the flood regulation supply and demand maps. The results quantify and illustrate complex ecosystem function–service–benefit relations in watersheds. Comparable procedures and calculation algorithms can be applied for other ecosystem functions and services relevant on the watershed scale. The approach is transferable to other regions and can provide important information for integrated watershed management.