Modeling the spatial distribution of multiple ecosystem services in Ilam dam watershed, Western Iran: identification of areas for spatial planning

The main purpose of current research is to quantify multiple Ecosystem Services (ESs) for the Ilam dam watershed, Western Iran. In this sense, the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) was applied to quantify water yield, sediment retention, and habitat quality, and Recreation Opportunity Spectrum (ROS) to model recreation for the current landscape (here 2021). Due to the inevitable exchanges between different types of ESs, in this study, Getis-ord Gi ∗ statistics were also used to describe the characteristics of service bundles spatial variation. This tool is used to measure spatial clusters – i.e. hotspots and coldspot –within the grid, which helps prioritize conservation measures. The results show that changes in water yield are mainly influenced by changes in precipitation, sediment retention and other actions of multiple factors such as Land use/cover (LULC) type, precipitation and temperature, while changes in recreation and habitat quality have the most dominant influence by LULC type. Moreover, the results of the spatial ESs bundle indicate that the hotspots show high value for a wide variety of services, which are occupied by high forests and grassland proportions. Otherwise, the ESs coldspots bundle has shallow values for most of the services. The low percentage of current hotspots indicates the difficulty of obtaining multiple ESs from one area, suggesting a protective priority to stop the loss of various services. Given that the increasing demand for ESs has put a lot of pressure on natural ecosystems, politicians and urban decision makers need to focus on the sustainable use of ecosystems so that the supply of ESs is not disrupted. Hence, this research can be crucial as detailed instructions to raise politician’s awareness and design a policy on ESs.