气候变化背景下中国天然草地物候特征及其气候驱动因子OACHSSCD

Under the background of climate change,research on vegetation dynamic changes and their responses to the environment has become one of the hot topics in ecology.As an important feature of biological responses to environmental changes,grassland phenology is a direct indicator of climate change.Systematic studies on the dynamic changes in grassland phenology and their responses to climate change are of great significance for ecosystem management and the formulation of adaptation strategies.China's natural grasslands have a wide distribution and complex and diverse climatic conditions,and their dynamic changes in response to climate change also exhibit significant regional differences and diversity in driving mechanisms.These characteristics make the research on the phenology of China's natural grasslands particularly important.From a national scale,this study systematically explored the characteristics of phenological changes in China's natural grasslands and their responses to climatic factors from 2001 to 2023 under the background of climate change,based on MODIS NDVI data from 2001 to 2023 and using methods such as univariate linear regression,Theil-Sen trend analysis,and Hurst index.The main conclusions are as follows:(1)The start of the growing season(SOS)of China's natural grasslands showed an overall advancing trend,with a spatial distribution gradually advancing from north to south and from west to east;the end of the growing season(EOS)showed an overall delaying trend,with a spatial change opposite to that of SOS;the length of the growing season(LOS)of grasslands showed an overall increasing trend,with a spatial distribution gradually increasing from north to south and from west to east.(2)The Hurst index prediction shows that the grassland phenology in most regions of China will maintain the same trend as in the past in the future,that is,SOS will advance,EOS will delay,and LOS will extend,but a small number of regions exhibit anti-persistence.(3)The LOS of China's natural grasslands is significantly affected by the combined effects of annual average temperature and precipitation,and the impact of precipitation is overall greater than that of temperature.There are significant differences in the responses of different grassland types to climatic factors.Tropical,warm-temperate,and temperate grasslands show a stronger response to precipitation changes,while alpine grasslands are more sensitive to temperature.This study aims to provide a scientific basis for grassland ecosystem management and resource utilization,and at the same time provide an important regional supplement and reference for global grassland ecological research.