Impacts of the grain for Green Program on the spatial pattern of land uses and ecosystem services in mountainous settlements in southwest China

The Grain for Green Program which is an important part of the strategy of Western development was initiated to protect the ecological environment and mitigate disasters. The upper reaches of the Min River basin is one of the key pilot regions for Grain for Green Program implementation in the mountainous areas of Sichuan Province, southwestern China. Therefore, monitoring the effect of the Grain for Green Program on the ecosystem services (ESs) in the montainous areas is important. Especially, several authors have emphasized the need to quantify spatial characteristics and evaluate ES values of land uses in mountainous areas from spatial and temporal perspectives. In this study, we firstly analyzed the spatial pattern of land uses in mountainous settlements before and after implementation of Grain for Green Program in the upper reaches of Min River, Sichuan Province of China. Based on lacunarity analysis, we explored the spatial characteristics of land uses including spatial heterogeneityand cluster. The results suggested that the spatial characteristics of land uses occurred at different scales, and there is strong relationship between spatial characteristic scales and the different distribution pattern of land use. We then quantified the relationships between geometrical features for land use pacthes and vegetation habitat suitability by multilevel Bayesian model. We found that the vegetation habitat suitability significantly affected on spatial location, size, and complexity of different land use patches in mountainous settlements. Based on assignment method of ES value per unit area, we finally quantitatively analyzed and compared the changes in ES values of land uses in mountainous settlements caused by Grain for Green Program from spatial and temporal scales. It is an important indicator for defining ecological potential by quantifying the change in ES value. After implementation of Grain for Green Program, the total ES value dramatically increased because of increase in forest and pasture areas. It suggests that the Grain for Green Program could bring effectively ecological benefit on protecting ecosystem functions in some degree. Application of spatial characteristics analysis of land uses and ES valuation in mountainous settlements to study the spatial structure of land use and service supplies should provide a better understanding of service provision and enable evaluation of the ecological integrity of land uses in mountainous areas.