Biodiversity patterns, palaeoecology and functional diversity across the "Great Ordovician Biodiversification Event" in the Basin and Range Province, USA

从那时起，阐明创造和维持生物多样性的过程一直是进化研究的核心问题，并且由于现代全球变化导致生物多样性丧失的风险越来越大，引起了人们的特别兴趣。古生物学研究为重建生物多样性的历史轨迹提供了最合适的工具，以揭示生物多样性的基本机制。内在因素，如捕食和种间竞争，建议发挥关键作用，但特别是后者的影响仍然知之甚少。对比模型将竞争描绘为多样化进程的驱动力或抑制剂。此外，有人认为，物种形成的速度本身是依赖于多样性的。一个可能的中介因素是种间竞争，其对多样化的影响可能在地球历史上发生了相当大的变化。在低多样性的生态系统中，低竞争使生物能够利用相当大的栖息地宽度。在更多样化的生态系统中，竞争的影响要大得多，这限制了生物群的生态最佳状态。随着栖息地饱和度的增加，生物被迫适应邻近的栖息地。这种从不饱和到饱和状态的相变解释了在深度时间多样化事件中观察到的两种效应：（1）较高系统水平的主要建立（或生存）与分支内多样化之间的滞后阶段，以及（2）多样性的相对突然增加。这种内在机制可以通过分析α和β多样性（多样性划分）来揭示。“奥陶纪生物多样性大事件”（GOBE）提供了一个完美的测试案例来解释内在因素的影响，它代表了整个中生代生物多样性最显著的上升。利用定量古生态学，多样性分区和功能多样性，该项目旨在揭示生物多样性的基本控制。盆岭省（美国）的寒武-奥陶纪层序非常适合成功地测试这些问题，因为它满足中心标准（沿沿着跨越GOBE的环境梯度的连续含油气地层）。这将是第一项通过在整个海洋生物的这一关键事件中在物种一级进行的全群落分析来跟踪阿尔法（栖息地内）和贝塔（栖息地之间）多样性的研究。预期结果对于评估社区一级的相互作用对生物多样化事件的总体影响至关重要。它还将有助于揭示以时代错误的框架条件为特征的时间间隔，从而完善对深层时间环境参数和进化过程的理解。

The elucidation of processes that create and maintain biodiversity has been a central question of evolutionary research ever since and attracted particular interest owing to the increasing risk of biodiversity loss due to modern global change. Palaeontological studies provide most suitable tools to reconstruct historical biodiversity trajectories in order to reveal fundamental mechanisms that underlie biodiversification. Intrinsic factors such as predation and interspecific competition are suggested to play a crucial role but especially the impact of the latter remains poorly understood. Contrasting models portray competition either as driver or inhibitor of diversification processes. Moreover, it has been suggested that the rate of speciation itself is diversity-dependent. A possible mediating factor is interspecific competition, whose impact on diversification may have changed considerable during Earth's history. In low-diverse ecosystems, low competition allows organisms to exploit a considerable habitat width. In more diversified ecosystems, competition has a much higher impact, which restricts biota to their ecological optimum. Through progressing habitat saturation, organisms are forced to adapt to adjacent habitats. Such a phase transition from unsaturated to saturated conditions explains two effects that have been observed in deep time diversification events: (1) a lag phase between the principal establishment (or survival) of higher systematic levels and within-clade diversification, as well as (2) a relatively sudden increase in diversity. Such intrinsic mechanisms may be revealed by the analysis of alpha- and beta-diversity (diversity partitioning). A perfect test case to account for the impact of intrinsic factors is provided by the "Great Ordovician Biodiversification Event" (GOBE) which represents the most significant rise in biodiversity of the whole Phanerozoic. Using quantitative palaeoecology, diversity partitioning, and functional diversity, this project aims to reveal fundamental controls on biodiversification. The Cambro-Ordovician succession of the Basin and Range Province (USA) is perfectly suited as it fulfils central criteria (continuous fossiliferous strata along an environmental gradient across the GOBE) to successfully test such questions. It will be the first study that tracks alpha- (within habitat) and beta- (between habitats) diversity by means of whole-community analysis carried out on the species level throughout this pivotal episode of marine life. The expected results will be crucial in assessing the impact of community level interactions on biodiversification events in general. It will furthermore help to expose time intervals that are characterized by anachronistic framework conditions, and thereby refining the understanding of environmental parameters and evolutionary processes in deep time.