Analysis Of Spatio-temporal Variation Characteristics And Driving Mechanism Of Vegetation Coverage In Daxing’an Mountains

Vegetation is the main component of terrestrial ecosystem.Vegetation coverage is an important indicator of surface vegetation status,and its change can be reflected by vegetation index(VI).Daxing ’an Mountains is located in the northwest of Heilongjiang Province and the northeast of Inner Mongolia Autonomous Region.It is the boundary between Inner Mongolia and Songliao Plain and an important ecological barrier in China.Based on MODIS-NDVI data from 2001 to 2019,meteorological data and socio-economic data in the same period,this study used ENVI5.3 and Arc GIS10.2 software to study the temporal and spatial variation characteristics of vegetation coverage in the Daxing ’an Mountains by means of maximum value synthesis(MVC),trend analysis,correlation analysis,principal component analysis,residual analysis and regression analysis.The driving forces of vegetation change in the Daxing ’an Mountains were discussed from both natural and social aspects,which provided a basis for vegetation restoration in the Daxing ’an Mountains.The main results are as follows :(1)The interannual NDVI of Daxing ’an Mountains fluctuated between 0.05 and 0.96,and the maximum NDVI appeared in 2019.Vegetation coverage increased slightly between2001 and 2019,with a growth rate of 0.01/10 a,and the vegetation coverage in the whole study area was good.During the 19 years,the vegetation coverage degradation areas were mainly distributed in the south and northwest of the study area.The areas with basically unchanged vegetation were mainly distributed in the central part of the study area,and the areas with improved vegetation were mainly distributed in the southeast of the study area.From 2001 to 2007,the NDVI values in most areas of the study area showed an increasing trend;from 2008 to 2019,the vegetation in most parts of the study area showed a downward trend.(2)The change of temperature and precipitation in Daxing ’an Mountains is not obvious.The temperature in the study area showed obvious zonal differences.The temperature decreased in the eastern part of the ridge line and increased in the western part of the ridge line.The precipitation in the study area showed obvious regional characteristics,and the precipitation from south to north changed from increasing to decreasing.Precipitation has a positive effect on the increase of NDVI in the southern part of the study area,while temperature has a positive effect on the increase of NDVI in the northern part of the study area.The decrease of NDVI in the northwest of the study area is caused by climate warming and drying.(3)Under the influence of different driving factors,population has the greatest impact on vegetation coverage,followed by GDP;the positive effect of social and economic development on vegetation cover is greater than the negative effect;the effects of climate change and human activities on vegetation cover change have spatial differences.Climate change dominates the improvement of vegetation in the southern part of the study area,human activities dominate the improvement of vegetation in the northern part of the study area,and climate change has little impact on NDVI.Human activities are the main factors for NDVI improvement.