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چکیده
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The aim of this study was to assess the ecosystem services including water yield (WY), sediment retention (SR), and sediment yield (SY) using the integrated valuation of ecosystem services and tradeoffs (InVEST) and their relationships were analyzed concerning land use, soil properties (clay, silt, sand, total porosity and bulk density) and topographic features (elevation, slope, aspect, TRI: terrain roughness index, and TPI: topographic position index) across the Shoor River basin in southwestern Iran. The results showed that the higher values of WY and SR were seen in the northern-eastern parts of the region while the SY was higher in western-southern parts. The average of WY, SR, and SY was estimated at 63 mm, 13.3 t ha−1 y−1 and 2.7 t ha−1 y−1, respectively. The highest WY (2828 m3 ha−1), SR (21 t ha−1 y−1), and SY (4.6 t ha−1 y−1) occurred in built-up areas, forests, and rangelands, respectively. The lowest rate of WY (348 m3 ha−1) and SR (2.2 t ha−1 y−1) were also found in agricultural lands but SY (0.9 t ha−1 y−1) in the forest lands. WY and SR had a positive and significant correlation with total porosity, sand fraction and all the topographic features except aspect (0.55 < R < 0.94, P-value <0.05), while they showed an inverse relationship with clay, silt and bulk density (−0.81 < R < -0.40, P-value <0.05). There was a weak to moderate correlation of the SY with all the topographic features and soil properties. Hot spot analysis also illustrated that all three ecosystem services are directly related to changes in topographic features and inversely related to soil properties across the basin. In general, the topographic features and soil properties had a higher influence on the WY and SR than on the SY. Moreover, the topographic features had more effect on the provision of all three ecosystem services than soil properties in the study area.
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