The relative contribution of species richness and species composition to ecosystem functioning

The influence of species diversity on ecosystem functioning has been the subject of many experiments and remains a key question for ecology and conservation biology. However, the fact that diversity cannot be manipulated without affecting species composition makes this quest methodologically challenging. We used partial Mantel tests to evaluate the relative importance of diversity and of composition on biomass production. Here, we applied partial Mantel tests (controlling for the other variable) on two datasets, the Jena (2002–2008) and the Grandcour (2008–2009) Experiment. In both experiments, plots were sown with different numbers of species to unravel mechanisms underlying the biodiversity-ecosystem functioning relationships. Contrary to Jena, plots were not mowed nor weeded in Grandcour, allowing external species to establish. Based on the diversity–ecosystem functioning and competition theories, we tested two predictions: 1) the contribution of composition should increase with time...物种多样性对生态系统功能的影响，已成为诸多实验的研究主题，亦是生态学与保护生物学领域的核心议题。然而，若要操控物种多样性，势必会同时改变物种组成，这使得该研究方向在方法论上颇具挑战。本研究采用偏曼特尔检验（partial Mantel tests），以评估多样性与物种组成对生物量生产的相对重要性。本次研究针对两个数据集——耶拿实验（Jena Experiment，2002–2008）与格朗库尔实验（Grandcour Experiment，2008–2009）——分别应用了控制另一变量的偏曼特尔检验。两项实验均通过播种不同数量的物种，以解析生物多样性-生态系统功能关系背后的潜在机制。与耶拿实验不同，格朗库尔实验中的样地未进行刈割或除草处理，允许外来物种定植。基于生物多样性-生态系统功能理论与竞争理论，我们验证了两项预测：1）物种组成的贡献应随时间推移而增强……