University of Mohaghegh Ardabili Water and Soil Management and Modelling 2783-2546 5 Special Issue : Climate Change and Effects on Water and Soil 2025 05 22 Sensitivity analysis of climatic factors in water yield modeling in the Talar watershed; an ecosystem service perspective Sensitivity analysis of climatic factors in water yield modeling in the Talar watershed; an ecosystem service perspective 101 120 3957 10.22098/mmws.2025.17808.1624 FA Mohsen Zabihi PhD of Watershed Management Sciences and Engineering, Department of Watershed Management Engineering, Faculty of Natural Resources, Tarbiat Modares University, Noor, Iran Hamidreza Moradi Professor, Department of Watershed Management Engineering, Faculty of Natural Resources, Tarbiat Modares University, Noor, Iran Abdulvahed Khaledi Darvishan Associate Professor, Department of Watershed Management Engineering, Faculty of Natural Resources, Tarbiat Modares University, Noor, Iran Mehdi Gholamalifard Associate Professor, Department of the Environment, Faculty of Natural Resources, Tarbiat Modares University, Noor, Iran Journal Article 2025 07 11 Understanding how climatic variables influence water yield is crucial for effective watershed management, particularly in regions that provide vital hydrological ecosystem services. This study investigates the sensitivity of key climatic factors— precipitation, reference evapotranspiration, and seasonality parameters—in modeling water yield ecosystem services using the InVEST model within the ecologically significant Talar watershed in northern Iran. Furthermore, the research aims to prioritize sub-watersheds based on their specific water yield to support ecosystem-based decision-making. Using a time series approach, water yield was modeled for the years 1989, 2000, and 2014, incorporating biophysical and climatic variables along with land use maps derived from Landsat TM and OLI imagery through SVM classification. A sensitivity analysis was conducted using the One-at-a-Time (OAT) method, with the year 2014 as the baseline and changes in each climatic factor assessed relative to 1989. Sub-watershed prioritization was carried out using specific water yield, defined as water yield per unit area. The results showed a declining trend in mean annual precipitation (from 552.6 mm in 1989 to 472.8 mm in 2014) and an increasing trend in temperature (from 8.92°C to 10.6°C), alongside a notable spatial shift in rainfall and evapotranspiration patterns. Sensitivity analysis revealed that water yield was most responsive to changes in precipitation, with a relative sensitivity index (Sr) approximately 0.42, indicating high model responsiveness. Reference evapotranspiration and seasonality parameters also exhibited a moderate influence. Prioritization results identified northern forested and agricultural sub-watersheds as having the highest specific water yields, highlighting their hydrological significance. These findings underscore the dominant role of precipitation variability in shaping regional hydrological services and emphasize the importance of spatially explicit watershed prioritization for sustainable water resource planning. The approach provides a practical framework for integrating ecosystem services into watershed management under climatic uncertainty and land use change, particularly in semi-humid regions like the Talar watershed. Understanding how climatic variables influence water yield is crucial for effective watershed management, particularly in regions that provide vital hydrological ecosystem services. This study investigates the sensitivity of key climatic factors— precipitation, reference evapotranspiration, and seasonality parameters—in modeling water yield ecosystem services using the InVEST model within the ecologically significant Talar watershed in northern Iran. Furthermore, the research aims to prioritize sub-watersheds based on their specific water yield to support ecosystem-based decision-making. Using a time series approach, water yield was modeled for the years 1989, 2000, and 2014, incorporating biophysical and climatic variables along with land use maps derived from Landsat TM and OLI imagery through SVM classification. A sensitivity analysis was conducted using the One-at-a-Time (OAT) method, with the year 2014 as the baseline and changes in each climatic factor assessed relative to 1989. Sub-watershed prioritization was carried out using specific water yield, defined as water yield per unit area. The results showed a declining trend in mean annual precipitation (from 552.6 mm in 1989 to 472.8 mm in 2014) and an increasing trend in temperature (from 8.92°C to 10.6°C), alongside a notable spatial shift in rainfall and evapotranspiration patterns. Sensitivity analysis revealed that water yield was most responsive to changes in precipitation, with a relative sensitivity index (Sr) approximately 0.42, indicating high model responsiveness. Reference evapotranspiration and seasonality parameters also exhibited a moderate influence. Prioritization results identified northern forested and agricultural sub-watersheds as having the highest specific water yields, highlighting their hydrological significance. These findings underscore the dominant role of precipitation variability in shaping regional hydrological services and emphasize the importance of spatially explicit watershed prioritization for sustainable water resource planning. The approach provides a practical framework for integrating ecosystem services into watershed management under climatic uncertainty and land use change, particularly in semi-humid regions like the Talar watershed. https://mmws.uma.ac.ir/article_3957_f91af8ce986ea9d9ee1345a2dd968d69.pdf