| Guanting Reservoir(GR)is an important drinking water source of Beijing.GR was forced to withdraw from the drinking water supply system of Beijing in 1997,after the comprehensive treatment,it was restored to Beijing as an alternate water source in 2007.During the period of reservoir treatment,the Zhangjiakou area in the upstream of GR Basin has made great sacrifices to reduce the pollution and protect the ecological environment,and its economic and social development subject to certain constraints.In order to explore the changes of ecosystem services and its driving factors,solving the problem of unbalanced development between the upstream and downstream of GR basin.On the one hand,this paper used InVEST model to evaluate water yield service and water quality purification service in 1995,2000,and 2010 respectively of GR basin.Analyzed and discuss the spatiotemporal variations and driving factors of these two services during 1995-2010.On the other hand,setting up returning farmland to forest and ecological protection these two reachable scenarios,to calculate the eco-compensation standard of GR basin from the view of ecosystem service value increment based on the idea of eco-compensation.And the major conclusions are as follows.(1)The water yield quantities of GR basin were 18.85 × 108 m3,7.59 × 108 m3,14.33 × 108 m3 in 1995,2000 and 2010 respectively.The water yield service was first weakened and then enhanced,and decreased by 24.0%during 1995-2010.The water yield quantities of 84.5%of GR basin decreased during 1995-2000,and 88.2%of GR basin increased during 2000-2010.Analysis the driving factors of water yield service,it is found that LULC and climate(precipitation)were important driving factors for water yield service change.(2)Total nitrogen(TN)outputs of GR basin were 4028.7 t,4137.9 t and 3611.4 t in 1995,2000 and 2010 respectively,total phosphorus(TP)outputs were 379.7 t,401.8 t and 354.0 t in 1995,2000 and 2010 respectively.TN outputs and TP outputs were both first increased and then decreased during 1995-2010.Water quality purification service first weakened and then enhanced.In general,TN purification service enhanced by 10.4%,and TP purification service enhanced by 6.8%during 1995-2010.The area which TN and TP outputs were lower had high vegetation cover.Vegetation cover and human activities are the main driving factors for the change of water quality purification service.The water quality purification service of GR basin was consistent with the development process of GR.(3)The water yield quantities of GR basin were 14.44×108 m3 under returning farmland to forest scenario,increased of 0.11×108 m3 over 2010.TN and TP outputs were 3432.3 t and 338.7 t under returning farmland to forest scenario respectively,increased of 179.06 t and 15.28 t over 2010 respectively.In space view,the area which water yield quantities increased and TN,TP outputs decreased were all located in the area returning farmland to forest.The water yield quantities of GR basin were 14.58×108 m3 under ecological protection scenario,increased of 0.25 X 108 m3 over 2010.TN and TP outputs were 3320.1 t and 327.2 t under ecological protection scenario respectively,increased of 291.26 t and 26.85 t over 2010 respectively.In space view,the area which water yield quantities increased and TN,TP outputs decreased were all located in the area returning farmland to forest and riparian buffer.(4)Under the returning farmland to forest scenario,increased ecosystem service value was 57.90 million RMB in total under this scenario,and the eco-compensation standard for the area that returning farmland to forest was 824.58 RMB/hm2.Under the ecological protection scenario,increased ecosystem service value was 121.55 million RMB in total under this scenario,and the eco-compensation standard for the area that carry out ecological protection was 1444.64 RMB/hm2.Taking into account the cost of forestation and ecosystem service value increment under different scenarios,ecological protection scenario was the better choice because of its higher earning ratio. |
PDF Full Text Request