Quantifying the Soil Erosion Control Ecosystem Service Under Climate Change in Gorganroud Watershed

By intensifing environment degradation as a result of increasing demand for ecosystem services, ecosystems will not be able to provide essential services for human communities in the near future. Therefore, it is essential to predict the effects of ecosystem change on service supply through modeling process. Hydrological models such as Soil and Water Assessment Tool (SWAT) have been proposed as robust tools for quantifying the ecosystem services in watersheds. Gorganrood watershed is one of the most important watersheds in the North of Iran which is highly affected by agricultural activities. In recent years, climate change, drought and human activities such as landuse change and deforestation have affected the potential of ecosystems in soil retention in Gorganroud watershed. Therefore, this study aimed to quantify soil erosion regulation ecosystem service under climate change using SWAT hydrological model. To achieve this purpose, after simulating monthly discharge and sediment in Arc SWAT, SUFI-2 algorithm was used to perform the combined calibration and uncertainty analysis process for 1976-1990. The model was then validated for 1991-1994. Values of NS= 0.7 and NS=0.64 indicate the satisfactory and good performance of SWAT model in simulating monthly discharge and sediment, respectively. Finally, the Erosion Control Index (ECI) was spatially quantified and mapped. The results show that the delivery level of erosion control service is severely affected by climate change. This research also shows that SWAT model can be used as a valueable tool for quantification of hydrological ecosystem services. However, further analysis is required after simulation.