How Does Water Diversion Directly and Indirectly Affect Land Use Change and Ecosystem Service : A Case Study of Baiyangdian Wetland, China

Baiyangdian wetland is called “Kidney in north China”, providing a wide range of ecosystem services that are important for human wellbeing. In the past few decades, the water scarcity and eco-environmental problems resulted from climate changes and human activities have become more and more serious. To relieve the pressure of water scarcity and ecological degradation, the government has implemented ecological water diversion projects (EWDPs) since 1992. The effect of EWDPs on ecosystem services should be paid more attention with careful quantification. In this study, land use and land cover change (LUCC) caused by EWDPs over three decades was analyzed to assess the impact of EWDPs on ecosystem services. Coefficients of ecosystem service value (ESV) calculation were improved for reginal ESV evaluation. The results showed that the area of construction, farmland and water increased by 6171, 2827, 1393 ha, respectively, and the total ESV increased by 8.04×108 CNY primarily due to that the regulating service increased with water area expansion. Redundancy analysis and socio-economic comprehensive analysis showed that EWDPs had the impact on water area and ESV with time-effectiveness and threshold effect. When the water diversion exceeded the threshold, the EWDPs affected LUCC and ESV directly. Otherwise, the EWDPs indirectly affected the ESV through influencing net primary productivity (NPP) or socio-economy. However, the impact of EWDPs gradually weakened as time passed, which could not keep sustainability. With the establishment of Xiong’an New Area and implementation of carbon neutrality policy, rational EWDPs will become crucial to achieve goals of ecological restoration