Spatiotemporal variations and their driving mechanism of vegetation coverage across Dongting Lake Basin from 2000 to 2021
Monitoring dynamic changes in vegetation cover is one of key factors for assessing environmental and governance effects.In this study,the Theil-Sen Median trend analysis along with Mann-Kendal was used to characterize the overall change trend of vegetation coverage across the Dongting Lake Basin based on the EVI time series data(2000～2021).Then,the intensity analysis was utilized to evaluate the spatiotemporal variations in EVI levels from 2000 to 2021 at the time interval,category and transition.The geographic detector model was employed to explain the natural driving forces of vegetation cover change.The results show that the EVI values in the growing season in the Dongting Lake Basin demonstrated a stage upward trend:an uptrend during 2000 to 2006 and 2012 to 2016 while a downtrend among 2007 to 2011 and 2017 to 2021.The area whose EVI increased was much larger than the area whose EVI decreased.The area with improved EVI accounted for 69.41％of the total area while the vegetation degradation areas for only 4.65％.The average annual change rate was relatively faster in the period of 2000～2010 than in the 2010～2021.In the 2000～2010,the gain of medium-high and low-medium vegetation coverage were active while the loss of high,medium and low-medium vegetation coverage was active;between 2010～2021,the gains of high,medium and low-medium vegetation coverage were active and the losses of medium and low-medium vegetation coverage were active.The spatial distribution of vegetation EVI in the Dongting Lake Basin was mainly affected by topographic and geomorphic factors.Among meteorological factors,the explanatory power of temperature on vegetation EVI was greater than that of precipitation.In the future,more attention should be paid to impacts of human activities(such as ecological engineering construction)on the dynamic changes in vegetation cover.The main environmental protection should be implemented in the study area according to EVI levels.
the Dongting LakeEVIspatio-temporal variationsintensity analysisgeographic detector
万方数据
维普
