未来气候变化下两种红景天植物的脆弱性

气候变化对全球的物种多样性有深远影响, 尤其是对高山物种多样性。研究未来气候变化下物种的灭绝风险对生物多样性保护具有重要的意义。本文针对青藏高原的2种重要药用植物大花红景天(Rhodiola crenulata)和菊叶红景天(R. chrysanthemifolia), 利用气候生态位因子分析法研究了它们对气候变化的敏感性、暴露性和脆弱性, 讨论了2种“共享社会经济途径” (SSP2-45和SSP5-85)情景下的未来气候对这2个物种脆弱性的影响。同时计算了2种红景天的气候生态位的边缘性和特化性, 通过主成分分析法对其气候生态位进行了二维可视化, 并分析了它们的气候变化脆弱性与气候生态位之间的关系。结果表明, 未来气候变化情景下2种红景天在其分布区都显示出西部脆弱性高而东部脆弱性低的特征, 而脆弱性都表现为较低的横断山脉地区将成为其未来气候避难所。2种红景天在SSP5-85气候情景下的脆弱性高于SSP2-45, 资源和能源密集型社会经济途径(即SSP5-85)将会增大物种的灭绝风险。此外, 被《中国物种红色名录》评估为无危的菊叶红景天的气候变化脆弱性反而大于被评估为濒危的大花红景天。生态位因子分析结果表明大花红景天的生态位边缘性和特化性都低于菊叶红景天, 研究推断同地区不同物种的气候变化脆弱性主要由物种的气候生态位决定。

Vulnerability of two Rhodiola species under climate change in the future

Aims: Climate change has a profound impact on global species diversity, especially alpine species diversity. Furthermore, the number of species currently threatened by climate change may increase as climate change. Studying the extinction risk of species under future climate change is of great significance to biodiversity conservation. Rhodiola crenulata and R. chrysanthemifolia are two important medicinal plants distributed on the Qinghai-Tibet Plateau. However, the potential effects of climate change on each species have not been widely researched. In this study, we investigate the vulnerability of each species to climate change and discuss the relationship between species vulnerability and climatic niche. In addition, we test whether climate change will affect the threat ranking of species in red list.
Methods: In this study, we studied the vulnerability of R. crenulata and R. chrysanthemifolia to climate change using climate-niche factor analysis. We then discussed the influence of climate on the vulnerability of both species change in the context of two “Shared Socioeconomic Pathways” (i.e. SSP2-45 and SSP5-85). Next, we calculated the marginality and specialization of the two species. At the same time, we visualized the climate niches of each species using principal component analysis and analyzed the relationship between climate niches and vulnerabilities of both species.
Results: Our results indicate that the vulnerability of each species is high in the western region of their range, and low in the eastern region of their range. Both species have lower vulnerability to climate change in the Hengduan Mountains, which will serve as a climate refugium for the two species. The vulnerability of the two species under SSP5-85 is higher than that under SSP2-45, and the resource- and energy-intensive socioeconomic pathways (i.e. SSP5-85) will increase the extinction risk of both species in the future. Rhodiola chrysanthemifolia, which is classified as Least Concern on China Species Red List, is more vulnerable to climate change than R. crenulata, which is classified as Endangered. Niche analysis demonstrates that niche marginality and specialization of R. crenulata were lower than that of R. chrysanthemifolia.
Conclusions: Our results suggest that the vulnerability of different species to climate change inhabiting the same region is primarily determined by the climate niche of each species. Climate change may affect the threat ranking of species in red list. It is necessary to consider the impact of climate change when assessing threats to species.