Contribution of ecological policies to vegetation restoration: A case study from Wuqi County in Shaanxi Province, China

Ecological policies can regulate and modify human activities, affecting land use, and eventually, regional vegetative cover. The impact of these policies on vegetation cover is mediated by natural factors as well as social and economic statuses. The former contains meteorological and topographical indicates, and the latter includes population density, per capita cultivated land, transportation convenience, etc. The chosen study area for this study was Wuqi County, situated in the northern Shaanxi Province of China. Using remote sensing and GIS spatial analysis techniques, land use and vegetation index data of Wuqi from 1995 to 2011 were obtained along with topographical, meteorological, and socio-economic data. Further, the vector and grid data were pooled using a village as a unit, to establish a spatial database in ArcGIS 10.2. Multiple regression models, including a geographically weighted model, along with spatial analysis, were applied to calculate the contribution of ecological policies to the vegetation restoration in the study area under the constraint of resource endowment, particularly ecological policies in terms of restoration of ecological land from cultivated land, conservation of forests and pastures. The results of spatial overlay showed an interesting spatial coupling between changes in land use and improvement in vegetation index. The results of the regression models could reveal the comprehensive and quantitative contribution of ecological policies to vegetation restoration since control variables such as resource endowments were included. Moreover, analyses based on both classical regression and geographically weighted regression indicated that land use has considerable influence on vegetation restoration, while the results of the latter showed a higher significance level and could reveal the spatial differences due to policy effects.