Identification of vegetation anomalous areas and driving forces in karst region of southwest China
Vegetation plays a vital role in the ecosystem.Differentiating between the effects of climate change and human activities on vegetation change is important in the context of vegetation restoration and management.In this study,Sen's slope and the Mann-Kendall test,correlation analysis,Copula function and geodetector were used to analyse the spatial and temporal changes of vegetation cover in the seven southwestern provinces from 2000 to 2020,and the correlation between climatic conditions,nighttime light data and normalized difference vegetation index(NDVI)to define anomalous regions and evaluate vegetation browning and greening probabilities under different climate and population pressures.Finally,the driving factors of vegetation change in anomalous regions are discussed.The re-sults of the study show that:1)69.04％of the vegetation in the study area has been improved,and the rate of vegetation recovery in karst areas has exceeded that in non-karst areas.2)The vegetation a-nomalous regions of temperature overlap with the areas of strong human activities and rising tempera-tures in the study area;the vegetation anomalous regions of precipitation are mainly located in the west-ern part of the Sichuan;and the anomalous regions of the two categories of human activities in terms of vegetation cover change are distributed in the urban areas of high population density and high nighttime light intensity.The two types of anthropogenic vegetation cover anomalies are distributed in the urban areas with high population density and high intensity of light at night.3)Temperature is more sensitive to vegetation than precipitation and higher than population density,vegetation in karst regions has a higher probability of being synchronous to climate change than in non-karst regions,and vegetation a-nomalous regions have a higher probability of being asynchronous to changes in the external environ-ment.4)The change of vegetation cover is mainly dominated by soil moisture content and nighttime light intensity,and there are mainly non-linear interactions between the influencing factors,with the strongest interaction between soil moisture content and nighttime light intensity.The results of the study help to explore the response mechanism of vegetation to the external environment,which is instructive for ecological restoration and vegetation protection planning in the southwest region.
万方数据
维普
