11. Spatial–Temporal Variation Analysis on Ecosystem Service Values in a Typical Inland River Basin, Northwest China

Ecosystem services value (ESV) is a direct manifestation of the change of ecosystem service function and benefits. In this study, we evaluated the value of 11 primary ecosystem services in the upper and middle region of Heihe River Basin (UMHRB) from 2000 to 2018. The spatial–temporal heterogeneity was explored at the grid-scale by using ecosystem service value model, and hot spot analysis. The results showed that: (1) The structure of land use in UMHRB was dominated by unused land, followed by grassland, farmland, forestland, water area and built-up land. The change trend of land use was the decrease of unused land and grassland, and the increase of built-up land, water area, farmland and forest land. (2) The temporal evolution of total ESV in UMHRB had shown a steady upward trend from 2000 to 2018. Among the ecosystem types, grassland and water area contributed the most to ESV. The trend of ESV changes showed that the ESV of unused land, grassland and forestland decreased, while the ESV of built-up land, farmland and water increased. For each individual ESV, hydrological regulation and climate regulation had the largest ESV contribution. Only the ESVs of climate regulation have slightly decreased, while other ecosystem services have increased. (3) The spatial distribution of ESV in UMHRB showed a spatially clustered distribution pattern and the degree of clustering was slightly weakened. From 2000 to 2018, the hot spots were mainly distributed in the southern Qilian Mountains, and sporadically scattered near reservoirs and rivers in the northern region. The cold spots were concentrated in the northern part near the desert area.