Study On Coupling Relationship Between Rock Desertification And Vegetation Phenology Characteristics In Guizhou Province

Vegetation is one of the most important components of terrestrial ecosystems.Studying the regional differences of vegetation phenology and its influencing factors is of great significance for understanding the process of terrestrial ecosystems.Studying the correlation between rocky desertification and vegetation phenology in Karst area is conducive to the better development of Karst rocky desertification control,and can also optimize the determination method of rocky desertification in small areas.Based on the 2015 MODIS NDVI data,this study used the Asymmetric Gaussian fitting method and the dynamic threshold method to extract the start of the forest(SOS)and the end of the season(EOS)of the forest phenology in Guizhou Province.And three phenological parameters of the growth season length(Length of season,LOS),the extracted phenological parameters and the temperature,precipitation distribution and altitude during the same period were analyzed to analyze the influence mechanism of vegetation phenology in the study area;The degree of rocky desertification in the study area is analyzed.The spatial and temporal differentiation of rocky desertification in the study area is analyzed.The correlation between rocky desertification and vegetation phenology in the study area is as follows:(1)The degree of rocky desertification in Guizhou Province was optimized from 2000 to 2015,with the turning point in 2005.After 2005,the optimized rate of rocky desertification increased and the incidence of rocky desertification decreased.(2)Karst rock desertification is affected by many aspects,including climatic conditions,social factors,and government regulation.Among them,rocky desertification has a good coupling relationship with the spatial distribution of precipitation.(3)Vegetation phenology in Guizhou Province is affected by many factors such as soil thickness,climate and altitude,and has a significant correlation with climate and altitude.Vegetation physiology SOS was negatively correlated,and LOS and EOS were positively correlated with the average temperature during the same period.The vegetation phenology SOS in Guizhou Province was significantly negatively correlated with the same period of precipitation.The vegetation phenology LOS was significantly positively correlated with the same period of precipitation,while the vegetation phenology EOS and the same period.The correlation between precipitation is weak.There was a significant positive correlation between vegetation phenology and elevation in Guizhou Province,and vegetation phenology EOS and LOS were highly negatively correlated with altitude.(4)The degree of rocky desertification is gradually serious,and the initial period of vegetation phenology also increases from east to west.The spatial distribution of vegetation phenology at the end of growth shows that the earlier the ending period,the higher the grade of rocky desertification,and vice versa.The lower the level of grading.In general,climate and elevation have an impact on the vegetation phenology of Guizhou Province,but the impact of climate and elevation on each phenological parameter is different.The vegetation phenology of SOS and LOS in Guizhou Province is more affected by terrain and climate than stone.The degree of desertification is highly coupled with vegetation phenology,and the coupling of SOS is more significant.