Missa Olivier, Dytham Calvin, Morlon Hélène
Institute of Biology, Ecole Normale Supérieure, 46 rue d'Ulm, Paris 75005, France
Biology Department, University of York, Wentworth Way, York YO10 5DD, UK.
Philos Trans R Soc Lond B Biol Sci. 2016 Apr 5;371(1691):20150226. doi: 10.1098/rstb.2015.0226.
Theoretical predictions for biodiversity patterns are typically derived under the assumption that ecological systems have reached a dynamic equilibrium. Yet, there is increasing evidence that various aspects of ecological systems, including (but not limited to) species richness, are not at equilibrium. Here, we use simulations to analyse how biodiversity patterns unfold through time. In particular, we focus on the relative time required for various biodiversity patterns (macroecological or phylogenetic) to reach equilibrium. We simulate spatially explicit metacommunities according to the Neutral Theory of Biodiversity (NTB) under three modes of speciation, which differ in how evenly a parent species is split between its two daughter species. We find that species richness stabilizes first, followed by species area relationships (SAR) and finally species abundance distributions (SAD). The difference in timing of equilibrium between these different macroecological patterns is the largest when the split of individuals between sibling species at speciation is the most uneven. Phylogenetic patterns of biodiversity take even longer to stabilize (tens to hundreds of times longer than species richness) so that equilibrium predictions from neutral theory for these patterns are unlikely to be relevant. Our results suggest that it may be unwise to assume that biodiversity patterns are at equilibrium and provide a first step in studying how these patterns unfold through time.
生物多样性模式的理论预测通常是在生态系统已达到动态平衡这一假设下得出的。然而,越来越多的证据表明,生态系统的各个方面,包括(但不限于)物种丰富度,并未处于平衡状态。在此,我们通过模拟来分析生物多样性模式如何随时间演变。具体而言,我们关注各种生物多样性模式(宏观生态或系统发育模式)达到平衡所需的相对时间。我们根据生物多样性中性理论(NTB),在三种物种形成模式下模拟空间明确的集合群落,这三种模式在母物种在其两个子物种之间的分配均匀程度上有所不同。我们发现,物种丰富度首先稳定下来,其次是物种面积关系(SAR),最后是物种丰度分布(SAD)。当物种形成时同胞物种之间个体的分配最不均匀时,这些不同宏观生态模式之间平衡时间的差异最大。生物多样性的系统发育模式需要更长时间才能稳定(比物种丰富度长数十到数百倍),因此中性理论对这些模式的平衡预测可能并不适用。我们的结果表明,假设生物多样性模式处于平衡状态可能并不明智,并为研究这些模式如何随时间演变提供了第一步。