Spatial And Temporal Characteristics And Driving Forces Of Vegetation Over The Tibetan Plateau

Climate change and human activities together lead to multi-scale ecosystem changes.At the regional scale,it is of great significance to explore the impact and contribution rate of human activities on the ecosystem for seeking ways of ecological restoration.As the largest plateau in China and the highest in the world,the Tibetan plateau has a vast area and a special geographical position,but its ecological environment is extremely fragile and sensitive.The spatiotemporal variation of NDVI and its driving forces over the Tibetan Plateau in the past 19 years were studied.The FLUS model was used to simulate and predict the future vegetation coverage of the Tibetan Plateau,and the vegetation coverage map of the Tibetan Plateau in 2028 was obtained.This study based on the Tibetan plateau region in 2000-2018 the normalized vegetation index(NDVI),meteorological data and socialconomic data,USES the trend analysis and residual analysis,relative importance calculation,FLUS vegetation coverage prediction methods,analyzed the nearly 19 years growing season of the Tibetan plateau vegetation coverage change rule,quantify the different types of human interference and predict the effects on the changes of vegetation coverage in the next decade the Tibetan plateau.This study provides a reliable scientific basis for the sustainable and coordinated development of the economy-society-ecological environment in the Tibetan plateau.The main research results of this article are as follows:(1)In terms of time variation,the NDVI of vegetation in the growing season of the Tibetan Plateau showed a fluctuating upward trend,and the monthly NDVI of vegetation in the growing season generally increased first and then decreased.The monthly variation rate was May(2.2%/10a)>,June(0.8%/10a)>July(0.5%/10a)>tember(0.4%/10a)> Au>(0.1%/10a).(2)In terms of spatial distribution,the average NDVI of the Tibetan Plateau was 0.33.The spatial distribution of vegetation NDVI in the growing season on the Tibetan Plateau during2000-2018 showed significant spatial differences,increasing from west to east and decreasing from northeast to southwest.On the trend of mean increase and decrease,the vegetation increase areas mainly distributed in the north of the study area,the alpine and arid area,the boundary of Qaidam Basin and Qilian Mountains,the mountainous grassland of Qilian Mountains,the southern wing of the eastern Himalayas,and the western Sichuan and eastern Tibet.Vegetation degradation areas include the Qiangtang Plateau basin,the semi-arid region in the middle of the Tibetan Plateau and the humid and sub-humid region in the east of the eastern mountains of Sichuan and Tibet.(3)In terms of sustainability and stability,the average Hurst index of the Tibetan Plateau is 0.45,indicating that the NDVI of the Tibetan Plateau is relatively weak in sustainability.The NDVI of the Tibetan Plateau is dominated by low stability and instability,and there is a certain spatial negative correlation with the sustainability of the NDVI.(4)There were 67.29% partial correlation between NDVI and average air temperature in the growing season of grassland on the Tibetan Plateau,and 67.67% partial correlation between NDVI and total precipitation in the growing season of grassland on the Tibetan Plateau.The NDVI of vegetation in the Tibetan Plateau is positively correlated with temperature and precipitation.(5)Based on the residual analysis of the impact of human activities on the vegetation of the Tibetan Plateau,61.16% of the total area has been promoted by human activities and 38.84%of the total area has been damaged by human activities.On the whole,human activities have promoted the vegetation in the Tibetan Plateau.Multiple regression equations were used to calculate the relative importance of five different types of human factors.The results showed that the dominant factors of vegetation change in different regions were different,which indicated that the development direction of different regions in the Tibetan Plateau was different,so the relative importance of vegetation change in different regions was different.(6)Is obtained by constructing FLUS model predicts 2028,the Tibetan Plateau vegetation situation,analysis the simulation results shows that the Tibetan plateau in 2028 in the low vegetation coverage,vegetation coverage,vegetation coverage,high vegetation coverage,vegetation covers an area of high proportion were 53.38%,12.08%,8.25%,3.67%,22.62%,and through the Tibetan Plateau in 2018 and 2028 the proportion of different levels of vegetation coverage change comparison results show that in the next 10 years the Tibetan Plateau vegetation will toward a good development trend.