Am Nat. 2021 Mar;197(3):312-323. doi: 10.1086/712781. Epub 2021 Jan 15.
AbstractChanges in temperature associated with climate change can alter species' distributions, drive adaptive evolution, and in some cases cause extinction. Research has tended to focus on the direct effects of temperature, but changes in temperature can also have indirect effects on populations and species. Here, we test whether temperature can indirectly affect the fitness of and by altering the nature of interspecific competition. We show that when raised in isolation, both and display similar variation in relative fitness across temperatures of 18°, 22°, and 25°C. However, has higher fitness than when experiencing interspecific competition at 18°C, while the inverse is true at 25°C. Patterns of fitness across thermal and competitive environments therefore indicate that the outcome of interspecific competition varies with temperature. We then use a coexistence experiment to show that is rapidly (within eight generations) extirpated when maintained with at 25°C. By contrast, remains as (or more) abundant than over the course of ∼10 generations when maintained at 18°C. Our results provide an example of how the thermal environment can affect interspecific competition and suggest that some species may become more prone to extinction under scenarios of climate change through indirect effects of the thermal environment on competitive advantages between species.
摘要气候变化引起的温度变化会改变物种的分布，推动适应性进化，在某些情况下还会导致物种灭绝。研究往往集中在温度的直接影响上，但温度的变化也会对种群和物种产生间接影响。在这里，我们通过测试温度是否可以通过改变种间竞争的性质来间接影响 和 的适应性。我们发现，当在隔离状态下生长时， 在 18°C、22°C 和 25°C 下的相对适应性变化具有相似的特征。然而， 在 18°C 下经历种间竞争时的适应性高于 ，而在 25°C 下则相反。因此，跨热环境和竞争环境的适应性模式表明，种间竞争的结果随温度而变化。然后，我们使用共存实验表明， 在 25°C 下与 共存时会迅速（在 8 代内）灭绝。相比之下， 在 18°C 下维持时，在大约 10 代的时间里仍然比 更丰富（或更丰富）。我们的结果提供了一个例子，说明热环境如何影响种间竞争，并表明在气候变化情景下，一些物种可能由于热环境对物种间竞争优势的间接影响而更容易灭绝。
