Recent responses to climate change reveal the drivers of species extinction and survival

Climate change may be a major threat to biodiversity in the next 100
years. Although there has been important work on mechanisms of decline in
some species, it generally remains unclear which changes in climate
actually cause extinctions, and how many species will likely be lost. Here
we identify the specific changes in climate that are associated with the
widespread local extinctions that have already occurred. We then use this
information to predict the extent of future biodiversity loss and to
identify which processes may forestall extinction. We used data from
surveys of 538 plant and animal species over time, 44% of which have
already had local extinctions at one or more sites. We found that
locations with local extinctions had larger and faster changes in hottest
yearly temperatures than those without. Surprisingly, sites with local
extinctions had significantly smaller changes in mean annual temperatures,
despite the widespread use of mean annual temperatures as proxies for
overall climate change. Based on their past rates of dispersal, we
estimate that 57–70% of these 538 species will not disperse quickly enough
to avoid extinction. However, we show that niche shifts appear to be far
more important for avoiding extinction than dispersal, although most
studies focus only on dispersal. Specifically, considering both dispersal
and niche shifts, we project that only 16–30% of these 538 species may go
extinct by 2070. Overall, our results help identify the specific climatic
changes that cause extinction and the processes that may help species to
survive.

气候变化或为未来百年间生物多样性面临的重大威胁。尽管学界已针对部分物种种群衰退的机制开展了重要研究，但目前仍普遍未能明确：究竟是哪些气候变化实际引发了物种灭绝，以及预计将有多少物种会因此消失。本研究明确了与已发生的广泛局地灭绝（local extinctions）相关的特定气候变化类型，并基于此预测未来生物多样性丧失的规模，同时识别出可延缓物种灭绝的关键过程。我们使用了针对538种动植物的长期监测数据，其中44%的物种已在至少一个监测点发生局地灭绝。分析结果显示，发生局地灭绝的监测点，其年度最高温的变化幅度更大、变化速率更快，均显著高于未发生灭绝的站点。值得注意的是，尽管学界广泛采用年平均气温作为整体气候变化的替代指标，但发生局地灭绝的站点，其年平均气温的变化幅度反而显著更小。基于过往的扩散速率，我们估算这538个物种中，有57%至70%将无法以足够快的速度完成扩散以避免灭绝。然而我们的研究表明，相较于扩散，生态位转移（niche shifts）似乎对物种避免灭绝更为关键——尽管当前多数研究仅关注扩散过程。具体而言，同时考虑扩散与生态位转移两种因素后，我们预测到2070年，这538个物种中仅16%至30%可能会灭绝。总体而言，本研究结果有助于明确引发物种灭绝的特定气候变化类型，以及可帮助物种存续的关键过程。