Identifying the World's Most Climate Change Vulnerable Species: A Systematic Trait-Based Assessment of all Birds, Amphibians and Corals

Climate change will have far-reaching impacts on biodiversity, including increasing extinction rates. Current approaches to quantifying such impacts focus on measuring exposure to climatic change and largely ignore the biological differences between species that may significantly increase or reduce their vulnerability. To address this, we present a framework for assessing three dimensions of climate change vulnerability, namely sensitivity, exposure and adaptive capacity; this draws on species’ biological traits and their modeled exposure to projected climatic changes. In the largest such assessment to date, we applied this approach to each of the world’s birds, amphibians and corals (16,857 species). The resulting assessments identify the species with greatest relative vulnerability to climate change and the geographic areas in which they are concentrated, including the Amazon basin for amphibians and birds, and the central Indo-west Pacific (Coral Triangle) for corals. We found that high concentration areas for species with traits conferring highest sensitivity and lowest adaptive capacity differ from those of highly exposed species, and we identify areas where exposure-based assessments alone may over or under-estimate climate change impacts. We found that 608–851 bird (6–9%), 670–933 amphibian (11–15%), and 47–73 coral species (6–9%) are both highly climate change vulnerable and already threatened with extinction on the IUCN Red List. The remaining highly climate change vulnerable species represent new priorities for conservation. Fewer species are highly climate change vulnerable under lower IPCC SRES emissions scenarios, indicating that reducing greenhouse emissions will reduce climate change driven extinctions. Our study answers the growing call for a more biologically and ecologically inclusive approach to assessing climate change vulnerability. By facilitating independent assessment of the three dimensions of climate change vulnerability, our approach can be used to devise species and area-specific conservation interventions and indices. The priorities we identify will strengthen global strategies to mitigate climate change impacts.

气候变化将对生物多样性产生深远影响，其中包括提升物种灭绝速率。当前用于量化此类影响的研究方法多聚焦于测算物种暴露于气候变化的程度，却在很大程度上忽略了可能显著改变物种脆弱性的种间生物学差异。为解决这一局限，我们提出了一套评估气候变化脆弱性三维维度的框架，即敏感性、暴露性与适应能力；该框架依托物种的生物学性状及其在未来预估气候变化下的模拟暴露情况构建。在迄今为止规模最大的同类评估中，我们将这套方法应用于全球鸟类、两栖动物与珊瑚类群（共计16857个物种）。本次评估最终明确了相对受气候变化脆弱性最高的物种，以及这些物种的集中分布地理区域：其中两栖动物与鸟类的集中分布区为亚马孙流域，珊瑚类的集中分布区为印度-西太平洋中部的珊瑚三角区（Coral Triangle）。我们发现，携带高敏感性与低适应能力性状的物种的集中分布区，与高暴露性物种的集中分布区存在显著差异；同时我们也识别出了那些仅基于暴露性的评估可能高估或低估气候变化影响的区域。研究显示，共有608至851种鸟类（占比6%至9%）、670至933种两栖动物（占比11%至15%）以及47至73种珊瑚（占比6%至9%）同时属于高度气候变化脆弱类群，且已被列入《国际自然保护联盟濒危物种红色名录（IUCN Red List）》，面临灭绝威胁。其余属于高度气候变化脆弱类群的物种，则为生物保护工作提供了新的优先保护对象。在较低排放情景的政府间气候变化专门委员会特别报告排放情景（IPCC SRES）下，高度气候变化脆弱的物种数量更少，这表明减少温室气体排放能够降低由气候变化引发的物种灭绝事件。我们的研究回应了学界日益增长的呼吁，即需要采用更具生物学与生态学包容性的方法来评估气候变化脆弱性。通过实现气候变化脆弱性三维维度的独立评估，我们的方法可用于制定针对特定物种与特定区域的保护干预措施及相关评价指数。本次研究确定的优先保护对象，将助力强化减缓气候变化影响的全球保护战略。