Analysis of vegetation cover change and its influencing factors of Qinba Mountains in Sichuan Province
The Qinba Mountains in Sichuan Province is an important ecological and water conservation protection area,with high vegetation coverage,but fragile and complex environment.A clear understanding of the changes of vegetation coverage and its influencing factors in this area is conducive to providing scientific basis for regional ecological protection and vegetation restoration,and providing guarantee for maintaining regional ecological security.Based on MODIS-NDVI data,the vegetation coverage of Qinba Mountains in Sichuan Province from 2001 to 2020 was estimated by pixel dichotomy,and its spatial and temporal changes,landscape pattern and influencing factors were analyzed by linear trend method,Hurst index,gravity center migration model,and optimal parameter geographic detector and other methods.The results were as follows:(1)From 2001 to 2020,the vegetation coverage of Qinba Mountains in Sichuan Province increased steadily at a rate of+0.0071/a,and the average vegetation coverage for many years was 0.6912.Except for the western part of the study area,the overall vegetation coverage was high in the north and low in the south.and the center of gravity of vegetation coverage at all levels was concentrated in the middle reaches of Jialing River and its vicinity.In the future,the trend of vegetation coverage will mainly be continue to increase and change from increase to decrease.(2)In the past 20 years,the fragmentation of the overall landscape pattern of regional vegetation coverage decreased,and the degree of aggregation increased.The low and medium vegetation coverage areas changed to high vegetation coverage areas,and high vegetation coverage has became the main vegetation coverage type.(3)Base on the optimal parameter geographic detector,the best research scale of the influencing factors of Qinba Mountains in Sichuan was 5km,and elevation,temperature and population density were the main influencing factors of vegetation coverage change in this area.