Data from: The evolutionary legacy of diversification predicts ecosystem function

Theory suggests that the structure of evolutionary history represented in a species community may affect its functioning, but phylogenetic diversity metrics do not allow for the identification of major differences in this structure. Here we propose a new metric, ELDERness (for Evolutionary Legacy of DivERsity) to estimate evolutionary branching patterns within communities by fitting a polynomial function to lineage-through-time (LTT) plots. We illustrate how real and simulated community branching patterns can be more correctly described by ELDERness and can successfully predict ecosystem functioning. In particular, the evolutionary history of branching patterns can be encapsulated by the parameters of third-order polynomial functions and further measured through only two parameters, the “ELDERness surfaces.” These parameters captured variation in productivity of a grassland community better than existing phylogenetic diversity or diversification metrics and independent of species richness or presence of nitrogen fixers. Specifically, communities with small ELDERness surfaces (constant accumulation of lineages through time in LTT plots) were more productive, consistent with increased productivity resulting from complementary lineages combined with niche filling within lineages. Overall, while existing phylogenetic diversity metrics remain useful in many contexts, we suggest that our ELDERness approach better enables testing hypotheses that relate complex patterns of macroevolutionary history represented in local communities to ecosystem functioning.理论研究表明，物种群落所承载的演化历史结构可能影响其生态系统功能，但现有系统发育多样性（phylogenetic diversity）指标无法识别该结构层面的显著差异。本研究提出一种全新指标——演化遗产多样性指数（ELDERness，全称Evolutionary Legacy of DivERsity），通过将多项式函数拟合至时间谱系（lineage-through-time, LTT）曲线，以此估算群落内部的演化分支模式。我们通过实例证实，ELDERness能够更精准地刻画真实与模拟群落的演化分支模式，并可有效预测生态系统功能。具体而言，演化分支模式的历史信息可通过三阶多项式函数的参数进行封装，且仅需两个参数——即"ELDERness曲面"即可完成量化。相较于现有系统发育多样性或演化分化指标，该参数组合能够更好地解释草原群落的生产力变异，且不受物种丰富度或固氮物种存在与否的影响。具体而言，ELDERness曲面较小的群落（对应LTT曲线中谱系随时间呈恒定积累的模式）生产力更高，这与互补性谱系结合谱系内部生态位填充所带来的生产力提升效应相符。总体而言，尽管现有系统发育多样性指标在诸多研究场景中仍具应用价值，但本研究提出的ELDERness方法能够更好地支持相关假说的检验——即验证局地群落所承载的宏观演化历史复杂模式与生态系统功能之间的关联。