Vegetation Cover Change and Its Response to Climate Change and Human Activities in the"Three-North"Project Afforestation Program
As an important ecological barrier in our country,the"Three-North Shelterbelt Project"(to build shelter belt in northeast,north,and northwest China)area has a fragile ecological environment.Studies on the temporal and spatial characteristics of vegetation cover can provide support for the ecological construc-tion of the project region.This paper,based on MODIS NDVI data,by adopting methods such as trend analysis,the Hurst exponent,and residual analysis,comprehensively investigated the spatiotemporal evolu-tion characteristics of vegetation cover and the impact of climate change and human activities on the vege-tation in the project region from 2001 to 2020.The results showed that 1)from 2001 to 2020,the NDVI of vegetation in the project region and its various construction zones showed an overall increasing trend.There were significant differences in the annual growth rates among different zones,with the Loess Plateau region>wind and sand area>Northeast and North China Plain Region>northwest sesert area.The spatial pattern of NDVI in the project region exhibited a pattern of higher values in the east,lower values in the west,higher values in the south,and lower values in the north.2)The improvement trend in the study area was evident,with significantly improved areas accounting for 45.9%.Among them,the proportion of sig-nificantly improved areas in the Loess Plateau region was significantly higher than those in other construc-tion zones.Future changes would be dominated by improvement,but sustainability would not be strong.3)In the project area,the NDVI of vegetation showed a positive correlation with temperature and precipi-tation.Human activities primarily contributed to the promotion of vegetation NDVI,with increasing trends observed both in NDVI and residuals for various land uses,and the trends were consistent.4)In areas of vegetation improvement and degradation,human activities played a dominant role in influencing vegeta-tion,with average contribution rates of 62.9%and 59.06%,respectively.Different zones showed distinct differences in the response of vegetation to human activities and climate change.In particular,the Loess Plateau region had the highest contribution rates to both vegetation improvement and degradation,account-ing for 75.36%and 71.4%,respectively.
万方数据
维普
