Ananlysis On The Change Of Vegetation Coverage And Its Influencing Factors In Xilingol League

It is of great significance to study the change of vegetation coverage in arid and semi-arid regions and explore its driving factors for the construction of local ecological security.We analyzed the spatial and temporal variation,2000-2018 years of Xilin Gol League area vegetation NDVI and making use of the Geodetector analysis research period of natural factors(annual precipitation,annual average temperature,vegetation type,soil type and geomorphologic types)and human factors(land use and land cover(LUCC)and population density)impact on vegetation NDVI changes.Here's what we found:1)From 2000 to 2018,the area of Medium and Low coverage vegetation,Medium and High coverage vegetation and High coverage vegetation increased in Xilin Gol League.Among them,the vegetation with Medium and Low coverage increased the most,from 8.77% to 36.61%.The area of Low vegetation coverage decreased significantly,from 87.87%to 48.50%.From the change trend,NDVI in the whole study area increased and decreased in space during the 19 years,showing an overall increasing trend.From the perspective of county change trend,the NDVI of vegetation increased most obviously in DUOLUN County,up to 0.0085;From the perspective of the trend of town change,SHIWUHAOXIANG of DUOLUN County has the largest increasing trend,reaching 0.0097;The NDVI of vegetation in YANGQUNTAN Township of ZHENGXIANGBAIQI Banner decreased most seriously,reaching-0.0018.In terms of the level of change,the south and northeast of the region showed improvement,while the north and east of the region showed a few scattered areas of degradation.DUOLUN County has the largest area of improvement,with an area of 2,000.7 km2.The most seriously degraded area is DONGWUZHUMUQINQI Banner,with an area of 107.9 km2.2)The average temperature in the study area was 3.274? during the study period.The annual variation of air temperature showed a slow rising trend in fluctuation,but the rising trend was not significant.The interannual variation of precipitation showed a slow decreasing trend in the fluctuation,but the decreasing trend was not significant.3)From 2000 to 2010,cultivated land,woodland and construction land increased in the study area.Grassland and water area decreased;Unused land doesn't change much.The main source of expansion for the other LUCC types is grassland,followed by water.From2000 to 2010,water area declined the most,losing 28.9% of its area compared with 2000.Unused land will be reduced from 2010 to 2018;Grassland and water area increased;The area of cultivated land decreased.However,the main source of expansion of construction land is grassland.4)From 2000 to 2018,the population in the study area was mainly concentrated in the south and central part of Xilingol League,with the southern part being the most widely distributed.The population is mainly distributed in the urban areas of various counties.From the perspective of spatial distribution,the population was obviously concentrated in cities and towns in 2010.5)In 2000,the factors affecting the NDVI of vegetation in the study area were ranked from large to small as follows: annual precipitation,soil type,annual average temperature,LUCC type,geomorphologic type,vegetation type and population density.In 2010,the influence degree of each factor on vegetation NDVI was ranked as follows: annual average temperature,soil type,annual precipitation,LUCC type,landform type,vegetation type and population density.In 2018,the influence degree of each factor on vegetation NDVI was ranked as follows: annual precipitation,annual average temperature,soil type,LUCC type,geomorphologic type,vegetation type and population density.6)In 2000,2010 and 2018,the relationship between the factors affecting the NDVI of vegetation in the study area showed two kinds of non-linear enhancement and double-factor enhancement.In 2000,annual precipitation ? annual mean temperature interaction has the greatest influence on NDVI,with an explanation rate of 63.4%.In 2010,the largest explanation rate is annual precipitation ? annual mean temperature,which is 65.4%.In 2018,the largest explanation rate is annual precipitation ?annual mean temperature,which is 50.5%.