Data from: Correlated evolution between climate and suites of traits along a fast-slow continuum in the radiation of Protea

Evolutionary radiations are responsible for much of Earth’s diversity, yet the causes of these radiations are often elusive. Determining the relative roles of adaptation and geographic isolation in diversification is vital to understanding the causes of any radiation, and whether a radiation may be labeled as ‘adaptive’ or not. Across many groups of plants, trait-climate relationships suggest that traits are an important indicator of how plants adapt to different climates. In particular, analyses of plant functional traits in global databases suggest that there is an “economics spectrum” along which combinations of functional traits covary along a fast-slow continuum. We examine evolutionary associations among traits and between trait and climate variables on a strongly supported phylogeny in the iconic plant genus Protea to identify correlated evolution of functional traits and the climatic-niches that species occupy. Results indicate that trait diversification in Protea has climate associations along two axes of variation: correlated evolution of plant size with temperature and leaf investment with rainfall. Evidence suggests that traits and climatic-niches evolve in similar ways, although some of these associations are inconsistent with global patterns on a broader phylogenetic scale. When combined with previous experimental work suggesting that trait-climate associations are adaptive in Protea, the results presented here suggest that trait diversification in this radiation is adaptive.

进化辐射（Evolutionary Radiation）造就了地球生物多样性的主体，然而这类辐射事件的成因往往难以捉摸。明确适应与地理隔离在物种分化中的相对作用，对于理解任何辐射事件的成因，以及判定该辐射是否属于"适应性辐射"均至关重要。在诸多植物类群中，性状与气候的关联表明，植物性状是其适应不同气候环境的重要指示因子。尤其值得注意的是，全球数据库中针对植物功能性状的分析显示，存在一类资源策略谱（economics spectrum），植物功能性状的组合沿该谱呈现出快慢连续的协同变化趋势。本研究依托标志性植物类群山龙眼属（Protea）的高支持度系统发育树，分析性状间以及性状与气候变量间的进化关联，以明确功能性状的协同进化模式与物种所占据的气候生态位（climatic niche）。研究结果显示，山龙眼属的性状分化与两类变异轴上的气候特征存在关联：植物体型与温度的协同进化，以及叶片资源投入与降雨量的协同进化。现有证据表明，性状与气候生态位的进化模式较为相似，但部分关联在更大尺度的系统发育框架下与全球模式并不一致。结合此前针对山龙眼属的实验研究（该研究表明性状-气候关联具有适应性意义），本研究结果证实该类群的性状分化属于适应性演化。