Analysis On The Characteristics Of Vegetation Coverage Change And Its Driving Factors In Typical Area Of Berikum Desert

Vegetation is the ecological barrier of arid desert area,and it is the green corridor between surrounding oasis and desert hinterland.Due to the fragile ecosystem in arid desert region,vegetation pattern variability is bigger and is greatly affected by ecological processes.The dynamic change process of vegetation cover in desertification region is analyzed to further determine the relationship between the temporal and spatial variation and various habitat factors,so as to provide theoretical basis for prevention and control of desertification.Taking the typical region of the Taklimakan Berikum Desert as the research area,Based on remote sensing image data and UAV monitoring technology,combined with field sampling data.the "vegetation coverage" and "terrain conditions","soil conditions" and "hydrological conditions" in the study area are analyzed systematically,and the direct and indirect factors affecting the vegetation coverage are discussed,Then,SEM model was used to analyze the change law and driving factors of vegetation coverage qualitatively and quantitatively.The conclusions are as follows:(1)The vegetation coverage in the study area shows obvious temporal and spatial differences.The main results are as follows: The vegetation in the whole region is sparse and unevenly distributed,and the vegetation coverage gradually decreases from the central region to both sides.On the time scale: from 2010 to 2019,the vegetation coverage of the Bilikum Desert is generally on the rise,with an area increase of 9443.63 m2,and the increase was 17.90%.On the spatial scale: The vegetation coverage in the south of the study area is larger and the distribution is more concentrated.from south to north,the vegetation fragmentation gradually increases,and the vegetation coverage gradually reduce;Combined with the changes of the river,the vegetation coverage near the ancient river is the largest.With the increase of the distance from the river,the vegetation coverage gradually decreases.(2)Characteristics of main factors affecting vegetation coverage.Overall relatively flat terrain,elevation and slope of small changes,but the spatial variability of slope direction is great,which is manifested by the slope direction in all directions and staggered distribution in space.The field sampling data show that the groundwater depth in the study area varies greatly,ranging from 0.15 m to 23.57 m,and presents a trend of gradual increase in groundwater depth from northwest to central to both sides.The soil particle size varies from 189.2 ?m to 410.0 ?m,and the overall average particle size is 258.0?m;The organic content was in the range of 34.32~48.95g/kg,and the change is small,with an average of 43.35g/kg.In the range of 240 ~ 260 cm,the organic content is the highest(3)Through the analysis of the spatial evolution of vegetation in the study area by the modified structural equation model(SEM),.The results showed that "hydrological condition" has the greatest influence on " vegetation coverage "(R = 0.890),followed by "soil condition"(R = 0.806),The terrain condition has indirect influence on vegetation coverage mainly through the comprehensive factors of hydrological condition and soil condition.(4)The structural equation model is predicted and modeled by R programming.Compared with the results of the current situation,the total influence coefficient of "terrain condition" on "soil condition" and "terrain condition" on " vegetation coverage " decreased.And "soil condition" and "terrain conditions" to "hydrological conditions" and " vegetation coverage" of the total influence coefficient are rising.According to the above results,the change and difference of plant coverage in time and space are mainly affected by hydrological conditions,and soil conditions are the second.