Vulnerability Assessment Of Climate Change Based On Community Productivity In Southwest Of China

Climate change has led to the vulnerability of ecosystems in Southwest China.Establishing a scientific vulnerability assessment system can effectively address the potential threats of climate change,and it has great significance to formulate environmental protection and climate change strategies in the Southwest.In this study,42 plots were set up in 3 mountainous areas in southwest China(Wolong in Sichuan,Fanjing Mountain in Guizhou,and Ailao Mountain in Yunnan).There were two questions to discusse through productivity of the community that acquired by measuring tree-ring:1)How to assess the vulnerability of ecosystems to climate change;2)How to assess the vulnerability of ecosystems to extreme drought events.The main results are as follows:1)Reflecting the vulnerability of ecosystems through the changing direction and probability of changes in community productivity,while reflecting the variability of ecosystems through the magnitude of changes in community productivity,and then exploring the impacts of climate change,climate gradients,stand factors on vulnerability and variability.The median value of the vulnerability index of early successional communities in Southwest China was close to-1,and its vulnerability is significantly higher than communities that in the middle and late succession stages(p<0.05).The vulnerability of forest ecosystem in Ailao Mountain is more higher than Wolong and Fanjing Mountain(p<0.1).Water deficit caused by climate warming is a limiting factor of vulnerability,and species diversity,density,volume are also the main influencing factors of vulnerability.The variability of early successional community was significantly higher than community that in the middle and late succession stages(p<0.05).The variability of ecosystem is significantly reduced with elevation(p<0.05).The ecosystem variability is restricted by temperature.And volume,tree height have a high explanatory power to ecosystem variability,4.0%and 5.4%respectively.2)Reflect the response of ecosystems to extreme drought events through the resistance,recovery and resilience of community productivity,and study the potential impacts of climate conditions,drought index,stand factors and succession stages on resistance,recovery and resilience.The resistance and resilience of the early successional communities in southwestern China were weaker than those in the middle and late succession stages(p<0.05).The forest ecosystem of Ailao Mountain was less resistant than Wolong and Fanjing Mountain(p<0.05).Resistance,recovery and resilience are limited by water deficit that caused by temperature increasing.Recovery is most strongly influenced by the combination of stand factors and climatic factors.And resilience is most mainly influenced by the stand factors independently.Therefore,in the southwestern region,the protection of low-latitude communities should be focused in forest management.It can reduce the restriction of water through reasonable thinning,and make the forest stand as soon as possible to get a positive succession through reasonable management in order to cope with long-term climate change and extreme drought events.