Comprehensive Evaluation Of Ecological Security In Arid And Semi-arid Area

Ecological system is an important place for human production and life,and its security is closely related to the sustainable development of human society.Arid and semi-arid regions are the most vulnerable regions of the global ecosystem.Due to the shortage of water resources and sparse vegetation coverage,there are many ecological problems,and their ecological security has been paid much attention.In this study,Ningxia Hui Autonomous Region in northwest China is selected as the study area.According to the characteristics of the study area,landscape ecological security index,ecosystem service value,and selected socio-economic indicators and natural indicators are used to comprehensively evaluate the ecological security of Ningxia Hui Autonomous Region.At the same time,ecological vulnerability is the core of ecological security,and in the process of urbanization,the fluctuation of ecosystem service value caused by the change of supply and demand of ecosystem services produces the scarcity value.Meantime,Ningxia Hui Autonomous Region is the main settlement area of The Hui nationality in China,and there are a large number of mosques in the region.As a kind of cultural landscape,the spatial distribution and land security of mosques have not been studied yet.Therefore,this study selects multiple indicators and perspectives to comprehensively evaluate the ecological security status of the study area.The main conclusions are as follows:(1)From 1990 to 2015,grassland was the largest land use type in Ningxia,and build-land was the smallest.At the same time,the area with the greatest change is unused land.However,the spatial distribution of the six types has little change.In the landscape indices at the level of type,grassland has the largest index value,followed by cultivated land,except that water area has the largest value in the Interspersion Juxtaposition index.At the landscape level,landscape shape index,Shannon diversity index and Shannon evenness index all showed an increasing trend from 1990 to 2015,except for peripheral-area fractal and contagion index.And from 1990 to 2015,the landscape ecological security index ofNingxia showed an overall trend of decreasing first and then increasing,and 2005 was the inflection point of change.The spatial distribution of landscape ecological security index in Ningxia is smaller in the north than in the south,and larger in the west than in the east.The change of landscape ecological security index is closely related to land use type.(2)The total number of mosques in the southern part of the study area is 2391,showing spatial aggregation distribution.Mosques are mainly distributed in areas with relatively low elevation and gentle slope.Meanwhile,from 1990 to 2015,LULC change direction model(LCDM)results of 0-6km buffer zone of mosque showed no significant regularity,which was caused by the fluctuation of forest and high-density grassland area in the buffer zone.The landscape pattern index in the 0-6km buffer zone showed that the distance from the mosque increased,the patch density increased,and the integral dimension of the surrounding surface increased.At the same time,the farther away from the mosque,the smaller the average patch area,the more patches,the closer the patches of the same land use type.(3)From 1990 to 2015,the ecological vulnerability of the study area showed an upward trend.In space,the north is larger than the south.At the same time,the EVI hot spots were mainly concentrated in the north of the study area,and the cold spots were mainly concentrated in the middle and south of the study area.At the same time,the analysis of driving factors shows that grassland area is the main driving factor of ecological vulnerability change,and grassland area is affected by both arid and semiarid climate and ecological engineering.(4)From 1990 to 2015,the value of ecosystem services in Ningxia showed a trend of decreasing volatility.In terms of spatial distribution,the ESV in the northwest is larger than that in the southeast,and the change of ESV in the middle is the most obvious and keeps increasing.Among the factors that affect the value of ecosystem service scarcity in Ningxia,demand-driven scarcity has the greatest impact on the value of ecosystem service scarcity.From 1990 to 2015,ESSV in Ningxia increased significantly.In terms of ecosystem service types,ESSV for air quality,waste disposal,soil conservation,biodiversity services and leisure culture increased significantly during the study period.This trend is the result of a combination of land use,population,per capita GDP and income levels.(5)From 1990 to 2000,the most important ecological security level in the region was relative security level,while from 2005 to 2015,the most important ecological security level in the region was critical security level.In terms of space,the ecological security level of the central is higher than that of the other regions of Ningxia,while the ecological security level of the southern is higher than that of the northern Ningxia.At the same time,the results of the Tupu showed that the transformation type of ecological security level changed the most from relative safety level to critical safety level during the study period,which mainly occurred from 2000 to 2005.In terms of spatial distribution,the transformation of ecological security grade occurred in the middle and south of the study area in 1990-1995 and 1995-2000,and the transformation distribution of ecological security grade occurred in the whole study area in other periods.To sum up,the ecological security situation in Ningxia Hui Autonomous Region can be analyzed and evaluated from multiple indicators and perspectives,which can provide scientific theoretical basis for decision-makers to formulate feasible regional sustainable development policies.