Spatial And Temporal Differences In Land Ecological Security And Risk In The North Shaanxi Energy Development Zone

Land is the material basis of human survival and development. With the acceleration of urbanization and industrialization process, the scope and intensity of land use continues to intensify. Human-land conflict and the contradiction between socio-economic development and ecological environment have become increasingly prominent, which caused ecological problems of land has been a serious threat to the sustainable development of human society and economy. The assessment and prediction of ecological security and ecological risk of land, is conducive to human understanding of ecological and environmental problems, and to develop sustainable development policies and measures in line with local conditions for their problems.Yulin City, is located in the northern of Shaanxi Province, is a typical farming-pastoral zone, the city is China's major energy base, that is extremely rich in mineral resources. With the development of Yulin City's economic and the mass exploitation of energy, environmental issues have become increasingly prominent. Firstly, according to the data of land use from 1990 to 2012, analysis the temporal variance of land use in Yulin, followed by selecting the risk index of drought, land use structure, soil erosion,land erosion, constructed land ecological risk evaluation model for Yulin City Land ecological risk comprehensive evaluation, finally through the P-S-R model of land ecological security in Yulin City of spatial-temporal dynamic evaluation, forecasting the ecological safety of Yulin from 2013 to 2030. Based on the data of 2012 set up different scenarios, we propose appropriate regulatory countermeasures. The main conclusions are as follows:(1) The study period, Yulin City construction land and woodland in an increasing trend, arable land, grassland, unused land is decreasing trend, the water remained unchanged. Arable land and grassland are the main land use types in Yulin, and land use structure changes significantly. Land use degree composite index of Yulin has shown an increasing trend, from the county perspective, Suide, Yuyang, Mizhi, the most dramatic changes, and being positive, is mainly related to their increased construction land, Fugu, qingjian, Shenmu, the extent of land use changes was negative, mainly related to their increased ecological land. Regional differences in land-use changes, regional differences around class R is greater than 1, the number of county:woodland, water was nine, arable land, construction land, unused land was eight, grassland was four.(2) The spatiotemporal difference of Ecological Risk Factors was big. Precipitation anomaly percentage of Yulin City, its index value areas are mainly located in the eastern part of the partial. Precipitation anomaly percentage index decreased first and then increased; regional ecological risk differences in land use structure changed significantly and largely, as a whole, the risk was first increased then decreased; more severe soil erosion mainly in the eastern region and the southern region, the mean increased first and then decreased, but its strength is still severe erosion levels; more severe sand erosion mainly in the northern region, the mean has been on a decreasing trend.(3) The change of Yulin City Land Ecological Risk Level in the overall is large, regional land ecological risk level differences are significant. In 1990, the ecological risk level belong ?, ? class county has seven, with larger risk. Where the greatest risk is Fugu County; In 2001, the ecological risk level belong ?, ? class county has still seven, with larger risk, and ecological unsafer, Where the greatest risk is Jiaxian; In 2012, the ecological risk slow down a bit, but belong to the ecological risk level IV, V class is still four counties, ecological security is still grim.(4) Yulin city ecological security index fluctuated growth trend overall, ecological security has improved. From the point of view of ecological safety evaluation level, 1990-2008, belongs to the state of insecurity,2009-2012, belongs to the critical safety or relatively safe. From the point of view of the county, the ecological security index of the county in Yulin increased in varying degrees, but most districts are still in a state of insecurity.(5) From 2013 to 2030, Yulin City, ecological security index is rising.2013--2017 years, the ecological security index is less than 0.45, ecosystem unsafe.2018-2021 years, the ecological security index is between 0.45 to 0.55, the ecosystem has improved, but instability, in the critical security state. After 2020, by the critical ecological security state into safer, and more stable, the ecosystem structure gradually improved, and the ecological environment has been greatly improved.(6) With the increase of elements of each subsystem, ecological security index showed an increasing trend, but the sensitivity of changes is different. Ecological Security Response subsystem maximum sensitivity, indicating that the largest impact on the ecological safety. Investment capacity and improve the technical level, to a certain extent, can improve the ecological safety.In this paper, the characteristics is that the exploratory evaluation of the land ecological risk for Yulin City. Selecting the drought, land use structure, soil erosion,sand erosion, constructed the regional ecological risk Comprehensive Assessment Model. In the evaluation of ecological security, selecting 1990-2012, nearly 22 years of scale, evaluate the temporal dynamics of land ecological security of Yulin city, a qualitative description of the ecological risk and ecological security relationship,and on the basis of land ecological security Yulin City predict a longer time scale, so forecasting is more scientific and accurate.