Tradeoffs/synergies of multiple ecosystem services based on land use simulation in a mountain-basin area, western China

Driven by economic and political influences, land-use change has become a significant factor impacting ecosystem service changes. It is vital to assess how multiple ecosystem services change under different scenarios for policy decisions pertaining to land use and ecological construction, especially for fragile mountainous areas. In this study, InVEST and scenario analyses are used to assess the changes of multiple ESs in Bailongiang watershed (BLJW), a typical mountain-basin ecotone in western China. Two indexes, ecosystem service change index (ESCI) and ecosystem service tradeoff degree (ESTD), are used to contrast the ESs change and its tradeoffs and synergies under land use scenarios, including urban and rural construction land expansion (URE), Grain for Green (GFG) and Scenario of Spatial Optimization of land use and land cover (SSO). Results show that under the URE scenario, watershed soil conservation and water yield increased with its ESCI of 3.0x10(-4) and 61.0x10(-4), respectively; and a slight decrease of carbon storage with its ESCI of -67.0x10(-4). Soil conservation, water yield and carbon storage increased under GFG scenario. In addition, there are some increases of soil conservation and carbon storage with the decrease of water yield in BLJW. Different tradeoffs/synergies relationships are illustrated for different land use scenarios. The service-oriented ESTD can be used to analyze the tradeoffs/synergies of multiple ESs and serve for ESs management. The SSO scenario of optimization of human activities and natural environmental systems, will be the win-win way for sustainable land use and ecosystem management in the mountain-basin area.