基于植被净初级生产力的青藏高原地区生态脆弱性及其控制因子分析

Ecological vulnerability and its driving forces of the Qinghai-Xizang Plateau based on the net primary productivity of vegetation

基于IPCC有关生态脆弱性的定义,采用净初级生产力(Net Primary Productivity,NPP)作为评估指标,结合地理探测器对2000—2020年青藏高原地区生态脆弱性的空间格局及控制因子进行分析。结果表明,青藏高原地区整体生态脆弱性较高,75%的地区处于中度及以上脆弱性水平,其中中南部脆弱性相对较高;不同土地利用类型的生态脆弱性差异较大,未利用地的生态脆弱性高于其他土地利用类型;青藏高原地区生态脆弱性主要由气候、植被、地形和土壤因子的交互作用所控制,其中植被指数与水蚀模数的交互作用影响最大,而单一因子的解释力相对较弱。本文强调了基于IPCC脆弱性定义的单一指标体系评价方法评估生态脆弱性的有效性,相关研究结果可为青藏高原地区的生态脆弱性评估和生态保护提供参考。

The Qinghai-Xizang Plateau is a typical ecologically-fragile area sensitive to climate change in China,and therefore a scientific assessment of the ecological vulnerability and its driving forces can help the sustainable development of the Qinghai-Xizang Plateau.However,previous studies mostly used a comprehensive evaluation index system,the application of which is largely limited by the high complexity and subjectivity of choosing the indicators.The single evaluation index system can not only effectively characterize the spatial pattern of ecological vulnerability,but also overcome the limitations of the above comprehensive evaluation index system and greatly reduce the dependence on data.Based on the definition of ecological vulnerability by IPCC,this study used Net Primary Productivity(NPP)to investigate the spatial patterns of the ecological vulnerability in the Qinghai-Xizang Plateau in 2000 and 2020 and then explored the driving forces by the Geodetector.The results show that the ecological vulnerability is overall high in the Qinghai-Xizang Plateau,with 75%of the land areas at a moderate or higher vulnerability level,and the vulnerability is relatively high in the central and southern parts of the region.Also,the ecological vulnerability differs greatly by the land use,with the relatively higher variability in unused lands.The ecological vulnerability of the Qinghai-Xizang Plateau is mainly controlled by the interactions of climate,vegetation,topography and soil,with the greatest contribution by the interaction between vegetation index and water erosion modulus,and yet the explanatory power of individual factor is small.This study emphasizes the effectiveness of using a single-index system to assess the ecological vulnerability according to the IPCC’s definition.The results of this study provide important insights for the ecological vulnerability evaluation and the ecological protection in the Qinghai-Xizang Plateau.