Analysis Of Land Use Change And Ecological Vulnerability On The Loess Plateau

Ecosystems serve as the basis for the sustainable development of human society.Affected by natural factors and human activities,the structure of the ecosystem in some regions of China has been damaged and ecological vulnerability has increased.As an essential geographical area in China,the Loess Plateau has become one of the ecologically fragile areas in recent years with the emergence of ecological problems such as soil erosion and desertification.At the same time,the government has introduced a series of ecological protection projects to improve the ecological environment,but the problem of regional ecological vulnerability still exists.Land use is a direct manifestation of the natural environment and human activities acting on the ecosystem,and their combined effect leads to changes in ecological vulnerability.Therefore,exploring the spatial and temporal changes in regional land use and analysing the spatial and temporal changes and driving mechanisms of ecological vulnerability can provide an important basis for regional ecological construction and sustainable development.In this study,the Loess Plateau is taken as the study area.The SRP model is used to construct an ecological vulnerability evaluation index system for the Loess Plateau at three levels: ecological sensitivity,resilience and pressure degree,taking into account the regional natural environment and socio-economic conditions.The principal component analysis method is used to calculate the regional ecological vulnerability index from 2000 to 2020,and the ecological vulnerability is graded according to the natural breakpoint method,and the spatial and temporal patterns of ecological vulnerability on the Loess Plateau are analyzed using the mass transfer and difference calculation methods.On the basis of the above research,the characteristics and changes of the ecological vulnerability of different land types analyzed,and a multiplicative model is used to calculate the comprehensive ecological vulnerability index of each county.A geographic probe was used to explore the driving factors and factor interactions of the spatial variation of ecological vulnerability using the selected indicator factors.Finally,the FLUS model was used to simulate land use changes in2035 on the Loess Plateau under different scenarios and to analyze their possible impacts on ecological vulnerability.The main conclusions drawn from the study are as follows:(1)From the perspective of spatial and temporal changes in land use on the Loess Plateau,the results show that the regional land use types from 2000 to 2020 are mainly arable land and grassland,and the area share of each land use type varies greatly.In terms of the comprehensive land use dynamic attitude,the comprehensive land use dynamic attitude index of the Loess Plateau from 2000 to 2020 shows an increasing trend.The comprehensive land use index shows an increasing trend,rising from 239.36 in 2000 to 239.36 in 2010 and then to 243.68 in 2020.2000-2020 land use dynamics increased from 0.18% to 0.63%,which indicates that human activities have increased and the intensity of land use transformation has increased.(2)An overall analysis of the ecological vulnerability of the Loess Plateau shows a moderate vulnerability,with a spatial distribution trend of high in the northwest and low in the northeast.The northern Qinling Mountains,the Luliang Mountains,and the Taihang Mountains,with their high vegetation cover and good ecology,are slightly fragile areas.The Guanzhong Basin has a flat topography and concentrated urban distribution,and the ecological environment in the urban agglomerations and surrounding areas is moderately and severely fragile due to human activities.The desert areas of the Inner Mongolia Autonomous Region are heavily and extremely vulnerable because the ground is relatively bare and the vegetation cover is low.The ecological vulnerability of the Loess Plateau has shown a clear downward trend over the past 20years;the ecological vulnerability of the northern Qinling Mountains and other areas with high vegetation cover is relatively stable;the ecological vulnerability of the urban built-up areas in the southeast has increased;and the ecological vulnerability of the Loess Hills and Ravines has been significantly improved through the implementation of a series of ecological restoration projects.(3)From the analysis of the ecological vulnerability of different land use types,the results show that the ecological vulnerability of forest and grassland is low,while the ecological vulnerability of construction land and bare land is high,and the ecological vulnerability of forest land and grassland shows a significant decreasing trend during the 20 years,while the ecological vulnerability of construction land and arable land shows a small increase.The results of analysing the ecological vulnerability of different counties show that the ecological vulnerability of about 300 counties all showed a decreasing trend to varying degrees during the study period,while 70 districts and counties showed an increasing trend,mainly in the main urban areas of Xi’an,Lanzhou,and Taiyuan.From a spatial perspective,the distribution of ecological vulnerability in each county is more concentrated,with areas of high ecological vulnerability distributed in counties such as Hangjin Banner in northwestern Inner Mongolia and Haiyuan County in southern Ningxia,while areas of low ecological vulnerability are scattered in the south of the region,with the scope gradually expanding.(4)The results of the Loess Plateau EVI driving survey show that,from a qualitative perspective,regional ecological vulnerability is influenced by a combination of natural and human factors.From the quantitative perspective,from 2000 to 2020,the explanatory power of vegetation cover,net primary productivity and dryness indicators on ecological vulnerability is always strong,indicating that natural factors play an important role in the change of ecological vulnerability.After the interaction of the drivers,the explanatory power of the spatial variation of ecological vulnerability is increased,indicating that ecological vulnerability is affected by a combination of factors such as urbanisation,vegetation cover and biodiversity.(5)FLUS model was used to simulate land use changes on the Loess Plateau in2035.The results show that under the natural development,urban development,and ecological protection scenarios,arable land and grassland are the main land use types in the region,but there are large differences in each land use type and conversion rate under different scenarios,and the differences are larger for construction land,arable land and forest land,and attention needs to be paid to the expansion of construction land and the reduction of arable land,resulting in changes in the ecological vulnerability of the region.