Landscape Ecology, Institute of Terrestrial Ecosystems, Department of Environmental Systems Science, Eidgenössische Technische Hochschule (ETH) Zürich, 8092 Zürich, Switzerland;
Unit of Land Change Science, Swiss Federal Research Institute for Forest, Snow and Landscape (WSL), 8903 Birmensdorf, Switzerland.
Proc Natl Acad Sci U S A. 2021 Oct 5;118(40). doi: 10.1073/pnas.2026347118.
Far from a uniform band, the biodiversity found across Earth's tropical moist forests varies widely between the high diversity of the Neotropics and Indomalaya and the relatively lower diversity of the Afrotropics. Explanations for this variation across different regions, the "pantropical diversity disparity" (PDD), remain contentious, due to difficulty teasing apart the effects of contemporary climate and paleoenvironmental history. Here, we assess the ubiquity of the PDD in over 150,000 species of terrestrial plants and vertebrates and investigate the relationship between the present-day climate and patterns of species richness. We then investigate the consequences of paleoenvironmental dynamics on the emergence of biodiversity gradients using a spatially explicit model of diversification coupled with paleoenvironmental and plate tectonic reconstructions. Contemporary climate is insufficient in explaining the PDD; instead, a simple model of diversification and temperature niche evolution coupled with paleoaridity constraints is successful in reproducing the variation in species richness and phylogenetic diversity seen repeatedly among plant and animal taxa, suggesting a prevalent role of paleoenvironmental dynamics in combination with niche conservatism. The model indicates that high biodiversity in Neotropical and Indomalayan moist forests is driven by complex macroevolutionary dynamics associated with mountain uplift. In contrast, lower diversity in Afrotropical forests is associated with lower speciation rates and higher extinction rates driven by sustained aridification over the Cenozoic. Our analyses provide a mechanistic understanding of the emergence of uneven diversity in tropical moist forests across 110 Ma of Earth's history, highlighting the importance of deep-time paleoenvironmental legacies in determining biodiversity patterns.
远离统一的带，地球热带湿润森林中的生物多样性在新热带地区和印度马来亚地区的高度多样性和相对较低的非洲热带地区的多样性之间存在广泛差异。由于难以区分当代气候和古环境历史的影响，这种跨不同地区的变化的解释，即“泛热带多样性差异”（PDD），仍然存在争议。在这里，我们评估了超过 15 万种陆地植物和脊椎动物中 PDD 的普遍性，并调查了当今气候与物种丰富度模式之间的关系。然后，我们使用与古环境和板块构造重建相结合的多样化空间显式模型，研究古环境动态对生物多样性梯度出现的影响。当代气候不足以解释 PDD；相反，简单的多样化和温度生态位进化模型与古干旱限制相结合，成功地再现了植物和动物分类群中反复出现的物种丰富度和系统发育多样性变化，这表明古环境动态与生态位保守性相结合具有普遍作用。该模型表明，新热带地区和印度马来亚地区湿润森林中的高生物多样性是由与山地抬升相关的复杂宏观进化动态驱动的。相比之下，非洲热带森林的多样性较低，这与新生代持续干旱化导致的较低物种形成率和较高灭绝率有关。我们的分析提供了对地球历史 1.1 亿年中热带湿润森林中不均匀多样性出现的机制性理解，突出了古环境遗产在确定生物多样性模式方面的重要性。
