Li Meng, Zhang Xianzhou, He Yongtao, Niu Ben, Wu Jianshuang
Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
University of Chinese Academy of Science, Beijing, China.
PeerJ. 2020 Feb 6;8:e8513. doi: 10.7717/peerj.8513. eCollection 2020.
Assessing ecosystem vulnerability to climate change is critical for sustainable and adaptive ecosystem management. Alpine grasslands on the Qinghai-Tibetan Plateau are considered to be vulnerable to climate change, yet the ecosystem tends to maintain stability by increasing resilience and decreasing sensitivity. To date, the spatial pattern of grassland vulnerability to climate change and the mechanisms that vegetation applies to mitigate the impacts of climate change on grasslands by altering relevant ecosystem characteristics, especially sensitivity and resilience, remain unknown. In this study, we first assessed the spatial pattern of grassland vulnerability to climate change by integrating exposure, sensitivity, and resilience simultaneously, and then identified its driving forces. The results show that grasslands with high vulnerability were mainly located on the edges of the plateau, whereas alpine grasslands in the hinterlands of the plateau showed a low vulnerability. This spatial pattern of alpine grassland vulnerability was controlled by climatic exposure, and grassland sensitivity and resilience to climate change might also exacerbate or alleviate the degree of vulnerability. Climate change had variable impacts on different grassland types. Desert steppes were more vulnerable to climate change than alpine meadows and alpine steppes because of the high variability in environmental factors and their low ability to recover from perturbations. Our findings also confirm that grazing intensity, a quantitative index of the most important human disturbance on alpine grasslands in this plateau, was significantly correlated with ecosystem vulnerability. Moderate grazing intensity was of benefit for increasing grassland resilience and then subsequently reducing grassland vulnerability. Thus, this study suggests that future assessments of ecosystem vulnerability should not ignore anthropogenic disturbances, which might benefit environmental protection and sustainable management of grasslands on the Qinghai-Tibetan Plateau.
评估生态系统对气候变化的脆弱性对于可持续和适应性生态系统管理至关重要。青藏高原的高寒草原被认为易受气候变化影响，然而该生态系统往往通过增强恢复力和降低敏感性来维持稳定。迄今为止，草地对气候变化的脆弱性空间格局以及植被通过改变相关生态系统特征（尤其是敏感性和恢复力）来减轻气候变化对草地影响的机制仍不清楚。在本研究中，我们首先通过同时整合暴露度、敏感性和恢复力来评估草地对气候变化的脆弱性空间格局，然后确定其驱动因素。结果表明，高脆弱性草地主要位于高原边缘，而高原腹地的高寒草地脆弱性较低。高寒草地脆弱性的这种空间格局受气候暴露度控制，草地对气候变化的敏感性和恢复力也可能加剧或减轻脆弱程度。气候变化对不同草地类型有不同影响。荒漠草原比高寒草甸和高寒草原更容易受到气候变化影响，因为其环境因素变化大且从扰动中恢复的能力低。我们的研究结果还证实，放牧强度（该高原高寒草地最重要的人为干扰的定量指标）与生态系统脆弱性显著相关。适度放牧强度有利于提高草地恢复力，进而降低草地脆弱性。因此，本研究表明，未来生态系统脆弱性评估不应忽视人为干扰，这可能有利于青藏高原草地的环境保护和可持续管理。
