[Characters of ecosystem vulnerability in southwestern China based on vegetation productivity]

Southwestern China is one of the most important areas for global biodiversity conservation. Under the background of global climate change, the vulnerability of this area has showed an increasing trend. According to the IPCC concept of vulnerability, we calculated the spatial distribution of ecosystem's vulnerability in southwestern China based on gross primary productivity (GPP) and then analyzed the spatial variation of different levels of vulnerability. Besides, we analyzed the relationship between environmental factors and ecosystem vulnerability, including precipitation, temperature, altitude, slope and vegetation type. The results showed that ecosystem vulnerability in the southwestern China gradually increased from southeast to northwest, with most area within the region being slight and mild vulnerable area (together occupied 69% of the total). The vulnerability level decreased with the increasing of mean annual precipitation and temperature but increased with increasing elevation and slope. Karst area in southwest and borders between farming and ranging regions in northwest Mountain ecotone of the study area had higher vulnerability, being more easily affected by climate change or other disturbances. The vulnerabilities of needle-leaved forest, grassland, and shrubland were relatively higher than other vegetation types, with the potential to be more easily affected by climate change.