| Ejina Oasis is located in the lower reaches of the Heihe River,it is a typical arid oasis in the northwest of China,and its ecological restoration maintenance and the degree of human exploitation directly affect the ecological security of the northern region of China and the strength of defense security in the border area.Based on this,this study selects the core area of Ejina Oasis in the lower reaches of the Heihe River as the study area,and takes the 2013 and2020 high-resolution remote sensing image data and the basic data of meteorology,vegetation,groundwater,population,water supply and tourism in the study area as the data sources,and adopts a combination of land use dynamic attitude and transfer matrix measurement,landscape pattern and landscape fragmentation index analysis,hot spot analysis and geo-detection analysis,etc.A systematic study of land use change,landscape pattern evolution,landscape fragmentation dynamics and landscape fragmentation driving mechanism in the core area of Ejina Oasis from 2013 to 2020 was conducted using a combination of research methods.The results showed that:(1)The land use types in the core area of Ejina Oasis are mainly unused land,forest land and grassland,and the sum of the three accounts for 90.98% of the total area in 2020,and their area ratios are 43.46%,24.81% and 22.70% respectively.The areas of arable land,water and construction land are relatively small,accounting for 4.26%,3.34% and 1.42% of the total area,respectively.From 2013 to 2020,the areas of construction land,grassland,arable land and unused land increase,and the dynamic attitude is 6.43%/a,0.42%/a,0.15%/a,0.09%/a;the area of watershed and forest land decreases,with motions of 0.79%/a and 0.65%/a,respectively.On the whole,natural land use types such as forest land,grassland and watershed degrade to unused land,or are transformed into man-made land use types such as construction land and cropland.(2)The changes of landscape pattern index in the core area of Ejina Oasis from 2013 to2020 are: PD does not change significantly,LSI decreases by 0.06,PAFRAC decreases by0.01%,LPI increases by 0.45%,AI increases by 4.17%,CONTAG decreased by 0.69%,SHDI increased by 0.01,and SHEI decreased by 0.05.Overall,the landscape shape tended to be simpler and more regular,landscape aggregation and dominance increased,landscape connectivity and evenness decreased,and landscape diversity and heterogeneity increased.(3)The landscape fragmentation in the core area of Ejina Oasis in 2013 and 2020 is "more high and higher grades than low and lower grades",and the landscape fragmentation dynamics in 2013-2020 is "mostly insignificant,with local changes,more hot spots than cold spots,and an increase in the overall degree of fragmentation",hot spot area(90% confidence level)accounted for about 28.55%,mostly for human interference intensity increased,natural water bodies and vegetation significantly degraded landscape type interlaced distribution area;cold spot area(90% confidence level)accounted for about 17.59%,mostly away from the water body,vegetation degradation,sand,saline land connected into a single landscape type concentrated distribution area.In a comprehensive view,the overall landscape fragmentation has increased.(4)The degree of landscape fragmentation in 2013,2020,and 2013-2020 in the core area of the Ejina Oasis is influenced by a combination of natural(temperature,precipitation,vegetation,groundwater)and anthropogenic(population,tourism,water supply)factors,with groundwater depth of burial,normalized vegetation index,tourist density,and water supply density being the main drivers of landscape fragmentation in the core area of the Oasis.There is an interaction enhancement effect among the drivers,and the strength of the interaction between natural and anthropogenic factors is more significant than that between the interactions within the two factors. |
