| As the global temperature rises,global warming has posed a great threat to the ecological environment on which human beings depend for survival.As an important part of the ecological environment,vegetation plays a huge role in wind and sand control,climate regulation and water conservation.However,with the population growth and rapid socio-economic development in China,human social activities have been intensifying their interventions on vegetation ecosystems,which,together with the variability of climate changes in different regions,make the dynamics of vegetation in China very complex.Net Primary Productivity(NPP)of vegetation refers to the portion of organic matter produced by photosynthesis in a unit time and unit area by vegetation minus the energy consumed by its own respiration,and is an important indicator to evaluate the security of terrestrial ecosystems and the carbon storage capacity of vegetation.The changes of its vegetation NPP are subject to the combined effects of natural factors such as climate and different human activities,and its changes are complex.This study explored the changes of vegetation NPP and the role of its influencing factors,and analyzed the interrelationship between vegetation and climate and human activities,which is important for understanding the ecological environment changes in China and can provide scientific basis for formulating corresponding environmental protection and ecological restoration policies.This study takes China as the research area,because human social and economic activities are mainly affected by the administrative management,China is divided into north China,northeast China,Northwest China,East China,Central China and southwest China;Based on vegetation net primary productivity,land use,meteorological data,night light data and per capita agricultural machinery total power,animal husbandry output proportion,urbanization rate said the intensity of social and economic activity data,etc.,study China’s vegetation cover climate and vegetation NPP characteristics and influencing factors of driving mechanism,the main research content and results are as follows:(1)The spatial and temporal characteristics of climate and vegetation NPP in China’s vegetation cover areas from 2001 to 2020 were studied by trend analysis,and it was found that China’s vegetation NPP and climate change have regional and stage-specific characteristics;during 2001-2020,China’s temperature,precipitation and vegetation NPP showed an increasing trend in each stage,and the temperature growth rate was high in the east and low in the west,with the fastest temperature increase in east China at Among the six regions,precipitation growth rates were lower in northwest and southwest China,at 0.71 mm/a and 1.71 mm/a,and higher in other regions;the growth rate of vegetation NPP gradually decreased from north to south,and the highest growth rate was 3.88 g C/(m~2·a)in northern China.The growth rate of vegetation NPP and precipitation in northern regions was faster in the first decade,while the growth rate of temperature was faster in the second decade.(2)The bias correlation analysis was used to study the response mechanism of vegetation NPP to climate change,and it was found that temperature and precipitation were positively correlated with vegetation NPP in China during 2001-2020.The highest partial correlation coefficient is 0.15 in North China,and the lowest is-0.10 in Southwest China.In the comparison of the partial correlation coefficients between 2001-2010 and 2011-2020,the vegetation NPP is affected by temperature in the latter stage,while the influence of precipitation is higher in the former stage,and the correlation coefficient with precipitation is not significant.The spatial distribution of correlation coefficients did not change significantly,and both significant positive and negative correlations decreased.(3)The study showed that human activities in China were negatively correlated with vegetation NPP during 2001-2020,with a mean residual value of-0.79 g C/(m~2·a)and a spatial distribution of low in the middle and high in the periphery.In 2001-2010 and 2011-2020,the residual mean value decreased from-0.42 g C/(m~2·a)in the first decade to-0.15g C/(m~2·a)in the second decade,with both negative and positive effects decreasing.The results of specific factor analysis showed that climate,anthropogenic land use change and anthropogenic intensity interaction terms were the main influencing factors on vegetation NPP change in China,with path coefficients of 0.86,0.15 and 0.33 in 2001-2010,and 0.37,0.58 and-0.08 in 2011-2020,respectively;from this,we can It can be seen that the significant effect of the interaction factor of human activity intensity decreases to different degrees in the six regions,while the significant positive effect of the factor of anthropogenic land use change increases to different degrees and the effect of climate effect weakens. |
PDF Full Text Request