Muir C D, Angert A L
Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, BC, Canada.
Department of Zoology, University of British Columbia, Vancouver, BC, Canada.
J Evol Biol. 2017 Dec;30(12):2189-2203. doi: 10.1111/jeb.13184. Epub 2017 Oct 20.
Local adaptation is commonly observed in nature: organisms perform well in their natal environment, but poorly outside it. Correlations between traits and latitude, or latitudinal clines, are among the most common pieces of evidence for local adaptation, but identifying the traits under selection and the selective agents is challenging. Here, we investigated a latitudinal cline in growth and photosynthesis across 16 populations of the perennial herb Erythranthe cardinalis (Phrymaceae). Using machine learning methods, we identify interannual variation in precipitation as a likely selective agent: southern populations from more variable environments had higher photosynthetic rates and grew faster. We hypothesize that selection may favour a more annualized life history - grow now rather than save for next year - in environments where severe droughts occur more often. Thus, our study provides insight into how species may adapt if Mediterranean climates become more variable due to climate change.
生物体在其原生环境中表现良好，但在原生环境之外则表现不佳。性状与纬度之间的相关性，即纬度渐变群，是局部适应最常见的证据之一，但确定受选择的性状和选择因子具有挑战性。在这里，我们研究了多年生草本植物红花沟酸浆（透骨草科）16个种群在生长和光合作用方面的纬度渐变群。使用机器学习方法，我们确定降水的年际变化是一种可能的选择因子：来自环境变化更大的南部种群具有更高的光合速率且生长更快。我们推测，在严重干旱更频繁发生的环境中，选择可能有利于更趋一年生的生活史——现在生长而不是为来年储存资源。因此，我们的研究为物种在气候变化导致地中海气候变得更具变化性时可能如何适应提供了见解。
