Research On The Spatiotemporal Variation Of Ecological Vulnerability And The Relationship Of Land Use In Gansu Province

China’s ecological fragility problem is prominent,especially the land degradation situation is very serious,and there are more serious phenomena such as grassland degradation,soil desertification,soil erosion,etc.In this context,the study of ecological vulnerability has attracted extensive attention in the academic community.Many scholars have begun to actively explore the mechanism,spatial and temporal patterns and spatiotemporal variation of ecological vulnerability,in order to achieve the suppression of ecological environment deterioration and remediation of ecological fragility.Sexual areas,the realization of the coordination and sustainable development of human society and ecological environment.This paper takes Gansu Province,a typical ecologically fragile area in the northwest,as an example.Integrate a variety of data sources such as meteorological data,terrain data,landscape data,remote sensing data,and economic population data.Comprehensive use of GIS and RS technology methods.A conceptual model of ecological vulnerability assessment based on “sensitivity-resilience-pressure” was constructed.The paper analyzes the status of ecological vulnerability,spatial and temporal evolution characteristics and the relationship with land use types in the study areas in 2000,2005,2010 and 2015.The main conclusions are as follows:(1)Analyze sensitivity,resilience,and stress in the study area.It was found that the spatial distribution of ecological resilience and ecological sensitivity is basically the same.It shows a trend of increasing sensitivity from the southeast to the northwest;The spatial distribution of ecological stress is closely related to the level of economic development and population density.(2)Analysis of the ecological vulnerability of the study area as a whole and the counties and cities.It is found that:(1)from a holistic perspective,the ecologicalvulnerability level of the study area in 2015 is relatively high,which is a level of intensity vulnerability.In terms of spatial distribution,there is a pattern of change that gradually decreases from northwest to southeast;(2)From the perspective of administrative divisions,1 extremely fragile city,6 vulnerable cities,5 moderately vulnerable cities,2 slightly vulnerable cities;87 counties: 6 extremely vulnerable counties,30 vulnerable counties,23 moderately vulnerable counties,27 mildly vulnerable counties,and 1 slightly vulnerable county.(3)Analysis of the ecological vulnerability evolution of the study area from 2000 to 2015.It was found that the ecological vulnerability index continued to decrease throughout the study period.The overall change shows a state of “first rapid decline(2000—2005)and then stabilization(2005—2015)”,and the area of the ecologically fragile decline area is always higher than the area of the ecological fragility increase.Studies have shown that ecological vulnerability changes are closely related to the original ecological conditions,human activities,local policies,etc.(4)Analysis of land use change in the study area from 2000 to 2015.Found:(1)The land use structure has not changed significantly.According to the proportion of land occupied by various types of land,the order from the largest to the smallest is unutilized land > grassland > cultivated land > forest land > construction land > water area;(2)According to the change area,the area of forest land,grassland and construction land increased,the water area remained basically unchanged,and the area of cultivated land and unused land decreased.(3)From the perspective of mutual transfer between land use types,conversion to forest land and grassland is an important direction for land use change in the study area from 2000 to 2005.The increase of forest land and grassland is still the main direction of land use change from 2005 to 2010,but the rate of change is smaller than the previous stage.The change in land use is mainly reflected in the rapid increase in construction land from2010 to 2015.(5)Analyze the relationship between land use types and ecological vulnerability in the study area from 2000 to 2015.It was found that the ecological vulnerability of different land use types is significantly different.Cultivated land is dominated by moderate vulnerability and intensity vulnerability;Woodland is dominated by mild vulnerability;Grassland is dominated by strength fragility;The waters are dominated by moderate and intensity vulnerabilities;Construction land use is dominated by moderate and intensity vulnerability;The unused land is basically characterized bystrength fragility and extreme strength.(2)The impact of land use change on ecological vulnerability is as follows: when the land use type is unchanged,its ecological vulnerability is mainly unchanged;When the type of land use changes,its ecological vulnerability also undergoes significant changes.