Regulation Mechanism Of Global Scale Ecosystem Stability

With the dramatic change of climate and decrease of biodiversity,the global vegetation ecosystem is facing a serious threat,and the research on the regulation mechanism of ecosystem stability is imminent.Ecosystem stability refers to the ability of ecosystem to maintain or restore its own structure and function,which is the key to maintain normal ecosystem service function.However,due to the complexity of ecosystem,there is much controversy about the dimensions and driving factors of stability.This article selects the other six continents except Antarctica as the study area,and FLUXNET data and remote sensing data from 1991-2014 as data sources.Based on the total primary productivity(GPP),species richness and precipitation,air temperature,shortwave radiation and other climate variables,the analyses of the global spatial pattern of the stability components,including time stability,resistance are conducted,and the relationships between the each composition are discussed.The main conclusions are as follows:(1)Internal relationships of ecosystem stability components.The multidimensional framework of ecosystem stability is universal on a global scale.Resilience is independent of resistance and temporal stability,and resistance is highly correlated with temporal stability in most cases.(2)The driving mechanism of ecosystem stability.On a global scale,climate is more important than biodiversity in regulating ecosystem stability.Climate factors accounted for70%,49% and 39% of the changes in temporal stability,resistance and resilience of ecosystem functions,respectively,while species richness accounted for only 5%,20% and-11%.(3)Spatial and temporal distribution characteristics of ecosystem stability dimension.The stability dimension fraction showed a unimodal pattern with altitude,and the stability reached a peak near 1800 m with obvious spatial and temporal distribution characteristics,showing significant latitude dependence,high dependence and community specificity.The temporal stability and resistance showed a similar spatial pattern.Both of them decreased with the increase of latitude and showed a quadratic curve with the change of altitude,showing a high stability in the evergreen broad-leaved forest.However,the resilience is independent of the two,which decreases first and then increases with the increase of latitude,and shows a cubic curve change with the increase of altitude,showing a high stability in the wetland.(4)Spatial and temporal distribution characteristics of ecosystem stability dimension.The stability dimension showed a strong latitude dependence and altitude dependence.The stability dimension presented a bimodal pattern with the change of latitude,and two peaks appeared near the equator and 25° north latitude.The stability dimension fraction showed a unimodal pattern with altitude and reached a peak value near 1800 m.There were significant differences in the stability dimension scores among the biomes.The stability dimension of the savanna ecosystem was the lowest,and that of the wetland ecosystem was the highest.A systematic study of ecosystem stability and its dimensions was carried out,which provided global evidence for the universality of multi-dimensional analysis of ecosystem stability,and proposed a new idea for the study of stability dimensions among different biomes.In addition,our study also found that climate is more important than biodiversity in regulating ecosystem stability at a large regional scale,which improved the understanding of ecosystem stability at a large spatial scale and revealed the transformation mechanism of ecosystem state under sustained climate change,thus providing a theoretical basis for the formulation of sustainable development strategies.