Spatial-temporal Changes Of Vegetation Net Primary Productivity In The Horqin Sandy Land Under The Background Of Ecological Restoration

Horqin sandy land is our country to implement the project of returning farmland to forest (grass) is the focus of one of the regions, in recent years, under the interaction of natural and human activities, the region's ecological environment has been restored. In order to monitor the ecological restoration of the area in real time, to reveal the inner mechanism of ecological restoration, This paper in the Horqin sandy land as the study area, under the support of RS and GIS technology, using satellite remote sensing and ground meteorological observation data, estimated from 2000 years of Inner Mongolia Horqin sandy land growth season (from April to October) of Vegetation Net Primary Productivity(NPP) and for the period of vegetation NPP and temperature, precipitation correlation analysis, revealing the Horqin sandy land vegetation NPP temporal and spatial variation characteristics and its response mechanism of climate change, and a combination of typical counties of land use, social and economic data of the impact of human activities on vegetation NPP, Draw the following conclusions:(1)Time variation shows::2000?2013, Horqin sandy land growing season NPP was fluctuant growth trend, the growth rate of 6.338 gC/m2/yr. 2000-2010 years, NPP changes more slowly, after 2010 increased sharply, reaching the highest value in 2013 (431.75gC/m2/yr). From the seasonal scale analysis, NPP in spring, summer and autumn showed an increasing trend. Among them, the most significant growth trend in the spring of NPP, the highest NPP value in summer, the strongest NPP volatility in autumn. Analysis of 2000?2013 from different types of sandy land in Horqin sandy land, different types of sandy land increased NPP. Among them, the growth rate of NPP in fixed sandy land was the largest, followed by flowing sand, and the NPP increase rate was the smallest (5.971 gC/m/yr)(2)Spatial variation characteristics:The average NPP of Horqin sandy land spatial distribution pattern showed a decreasing trend from southeast to northwest. This is consistent with the water and heat conditions and vegetation distribution in the area. NPP high value areas are mainly distributed in Horqin Left after the flag of the southern, Horqin Left Wing Middle Banner in southeastern area; low NPP value area mainly distributed in Eastern Wengniute Banner, baarin Right Banner, the southern region. And in the 14 years, the area of NPP is increasing, and the area of NPP is low. In the study period, the Horqin sandy land growth season NPP showed an increasing trend of the area proportion was 92.16%, which significantly, significantly increased the area proportion respectively 31.59% and 17.53%, mainly distributed in parts of Naiman Banner and Kulun in most areas, Aohan banner, southern, Ongniud Banner in parts of the Northeast, Horqin Left Wing Middle Banner, Horqin Left wing rear banner southwest; NPP values showed a significant decrease in the regional area is very small, mainly distributed in Balinyou banner, Horqin Right Wing Middle Banner. From the analysis of seasonal scale, Horqin Sandy Land in different seasons NPP increased the area larger than the decreased area. Among them, the area of NPP was the most significant increasing trend in spring, accounting for 42.43% of the total area of the whole study area. The summer NPP showed a significant reduction in the area of the largest, accounting for 1.12% of the total area of the study area. Analysis from the different types of sandy land, fixed and semi fixed sandy land NPP is higher, followed by semi mobile sand, flowing Sandlot NPP was the lowest, which might related to the different with different types of sandy land in response to climatic change and human activity.(3) Analysis of influencing factors:Horqin Sandy Land NPP and precipitation was significant positive correlation with temperature was negatively correlated, precipitation is an important weather factors affect the productivity of vegetation change. Through the analysis of the typical area land use, population, economic structure and policy evolution shows that the impact of human activities on vegetation productivity in Horqin Sand Land can't be ignored, and in some extent reflects the effectiveness of the ecological restoration project.