Li Weixi, Wang Runxi, Liu Ming-Fai, Folk Ryan A, Xue Bine, Saunders Richard M K
Division of Ecology & Biodiversity, School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong SAR, China.
Department of Biological Sciences, Mississippi State University, Starkville, MS, United States.
Front Plant Sci. 2024 Mar 8;15:1287171. doi: 10.3389/fpls.2024.1287171. eCollection 2024.
Tropical forests harbor the richest biodiversity among terrestrial ecosystems, but few studies have addressed the underlying processes of species diversification in these ecosystems. We use the pantropical flowering plant family Annonaceae as a study system to investigate how climate and biogeographic events contribute to diversification. A super-matrix phylogeny comprising 835 taxa (34% of Annonaceae species) based on eight chloroplast regions was used in this study. We show that global temperature may better explain the recent rapid diversification in Annonaceae than time and constant models. Accelerated accumulation of niche divergence (around 15 Ma) lags behind the increase of diversification rate (around 25 Ma), reflecting a heterogeneous transition to recent diversity increases. Biogeographic events are related to only two of the five diversification rate shifts detected. Shifts in niche evolution nevertheless appear to be associated with increasingly seasonal environments. Our results do not support the direct correlation of any particular climatic niche shifts or historical biogeographical event with shifts in diversification rate. Instead, we suggest that Annonaceae diversification can lead to later niche divergence as a result of increasing interspecific competition arising from species accumulation. Shifts in niche evolution appear to be associated with increasingly seasonal environments. Our results highlight the complexity of diversification in taxa with long evolutionary histories.
热带森林拥有陆地生态系统中最丰富的生物多样性，但很少有研究探讨这些生态系统中物种多样化的潜在过程。我们以泛热带开花植物番荔枝科为研究系统，来探究气候和生物地理事件如何促进物种多样化。本研究使用了基于八个叶绿体区域构建的包含835个分类单元（占番荔枝科物种的34%）的超级矩阵系统发育树。我们发现，相较于时间和恒定模型，全球温度或许能更好地解释番荔枝科近期的快速多样化。生态位分化的加速积累（约1500万年前）滞后于多样化速率的增加（约2500万年前），这反映出向近期多样性增加的异质性转变。生物地理事件仅与所检测到的五次多样化速率变化中的两次有关。然而，生态位进化的变化似乎与季节性日益增强的环境有关。我们的研究结果并不支持任何特定的气候生态位变化或历史生物地理事件与多样化速率变化之间存在直接关联。相反，我们认为番荔枝科的多样化可能会由于物种积累导致种间竞争加剧，从而引发后期的生态位分化。生态位进化的变化似乎与季节性日益增强的环境有关。我们的研究结果凸显了具有悠久进化历史的分类群多样化的复杂性。
