Fernandes Lucas D, Hintzen Rogier E, Thompson Samuel E D, Barychka Tatsiana, Tittensor Derek, Harfoot Michael, Newbold Tim, Rosindell James
Department of Life Sciences, Imperial College London, Silwood Park, Buckhurst Road, Ascot, Berkshire, SL5 7PY, UK.
Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6BT, UK.
Syst Biol. 2025 Jun 12;74(3):469-482. doi: 10.1093/sysbio/syaf006.
The total number of species on earth and the rate at which new species are created are fundamental questions for ecology, evolution and conservation. These questions have typically been approached separately, despite their obvious interconnection. In this study, we approach both questions in conjunction, for all terrestrial animals. To do this, we combine two previously unconnected bodies of theory: general ecosystem models and individual-based ecological neutral theory. General ecosystem models provide us with estimated numbers of individual organisms, separated by functional group and body size. Neutral theory, applied within a guild of functionally similar individuals, connects species richness, speciation rate, and number of individual organisms. In combination, for terrestrial endotherms where species numbers are known, they provide us with estimates for speciation rates as a function of body size and diet class. Extrapolating the same rates to guilds of ectotherms enables us to estimate the species richness of those groups, including species yet to be described. We find that speciation rates per species per million years decrease with increasing body size. Rates are also higher for carnivores compared to omnivores or herbivores of the same body size. Our estimate for the total number of terrestrial species of animals is in the range 1.03-2.92 million species, a value consistent with estimates from previous studies, despite having used a fundamentally new approach. Perhaps what is most remarkable about these results is that they have been obtained using only limited data from larger endotherms and their speciation rates, with the predictive process being based on mechanistic theory. This work illustrates the potential of a new approach to classic eco-evolutionary questions, while also adding weight to existing predictions. As we now face an era of dramatic biological change, new methods will be needed to mechanistically model global biodiversity at the species and individual organism level. This will be a huge challenge but the combination of general ecosystem models and neutral theory that we introduce here is a way to tractably achieve it.
地球上物种的总数以及新物种产生的速率是生态学、进化生物学和保护生物学的基本问题。尽管这些问题明显相互关联，但通常是分别进行研究的。在本研究中，我们将这两个问题结合起来，针对所有陆生动物进行探讨。为此，我们整合了两个此前未关联的理论体系：通用生态系统模型和基于个体的生态中性理论。通用生态系统模型为我们提供了按功能组和体型划分的个体生物数量估计值。在功能相似个体的群落中应用中性理论，可将物种丰富度、物种形成速率和个体生物数量联系起来。综合起来，对于已知物种数量的陆生恒温动物，它们为我们提供了物种形成速率随体型和食性类别变化的估计值。将相同的速率外推到变温动物群落，使我们能够估计这些类群的物种丰富度，包括尚未被描述的物种。我们发现，每百万年每个物种的物种形成速率随体型增大而降低。相同体型的食肉动物的物种形成速率也高于杂食动物或食草动物。我们对陆生动物物种总数的估计在103万至292万种之间，尽管采用了全新的方法，但该值与先前研究的估计结果一致。或许这些结果最引人注目的是，它们仅基于来自大型恒温动物及其物种形成速率的有限数据得出，且预测过程基于机制理论。这项工作展示了一种解决经典生态进化问题新方法的潜力，同时也为现有预测提供了支持。鉴于我们现在正面临生物剧烈变化的时代，将需要新的方法来在物种和个体生物层面上对全球生物多样性进行机制建模。这将是一项巨大的挑战，但我们在此引入的通用生态系统模型和中性理论的结合是一种可有效实现这一目标的途径。
