Impacts Of Migration And Relocation Planning On Ecosystem Service

Migration and relocation is one of methods to repair damaged ecological environment, relieve the problem of the livelihood of farmers, and keep ecological security. The key scientific problems is to answer where resettlement, and how to achieve ecological benefit. This study selected the watershed of south-to-north water transfer project, the Danjiangkou reservoir upstream of Ankang municipality in Shaanxi province as the research object. Selecting reasonable index system of Ankang municipality resettlement suitability evaluation, combined with the policy of returning farmland to forest was designed in 2015 and 2020, and compare to 2010 with the function of water supply, water purification, soil erosion control and carbon sequestration service, It is show that:(1) Land use and land change in ankang municipality are forest, shrub, grassland, wetland, farmland, urban land and bare land. Each type accounted for 47.8%, 29.1%, 0.8%, 0.9%,20.9%, 0.3% and 0.2%. Compared with 2000 forest, farmland, urban land changes significantly, most of farmland and bare land transfer into forest and urban land.(2) Based on the slope, the distance from main road, the distance from town, land use type and the distance from nature reserve, synthetically got land suitability grade for relocation. It is divided into five grades, which grade Ⅰ area accounted for 37.4% of the total area of Ankang municipality, levelⅡis 20.9%, level Ⅲ accounted for 21.0%, level Ⅳ is 11.7% and level Ⅴ accounted for 8.3%, relocation area are chose from level Ⅲ to Ⅴ.(3) Based on 2010, according to land suitability grade for relocation, got LUCC of 2015 and 2020. Resettlement lead to changes in land use type, 476 km2 is changed during 2010 to 2015, in which 461 km2 of farmland transfer into forest, 6 km2 of grassland and 9 km2 of bare land into town. 389 km2 is changed during 2015 to 2020, in which 372 km2 of farmland transfer into forest and 17 km2 of grassland transfer into urban land.(4) Compared with 2010, ecosystem services, water yield in 2015 decreased by 0.2%, nitrogen export fell 4.3%, phosphorus export fell 5.5%, the sediment export fell 1.7%, carbon content increased by 3.0%; Water yield decreased by 0.7% in 2020, 7.0% less nitrogen output and nitrogen output fell 9.0%, phosphorus output fell 5.1%, the carbon sequestration increased by 5.5%.(5)Migration and relocation planning in Ankang lead water purification, soil erosion control service and carbon sequestration service enhancement, but reduce water supply services, although migration and relocation policy have enhancement effect on ecosystem services as a whole, but also need to pay attention to trade-off the ecosystem services.