IRD, DIADE, University of Montpellier, Montpellier, France.
AMAP Lab, IRD, CIRAD, CNRS, INRA, University of Montpellier, Montpellier, France.
Biol Rev Camb Philos Soc. 2021 Feb;96(1):16-51. doi: 10.1111/brv.12644. Epub 2020 Sep 13.
Tropical Africa is home to an astonishing biodiversity occurring in a variety of ecosystems. Past climatic change and geological events have impacted the evolution and diversification of this biodiversity. During the last two decades, around 90 dated molecular phylogenies of different clades across animals and plants have been published leading to an increased understanding of the diversification and speciation processes generating tropical African biodiversity. In parallel, extended geological and palaeoclimatic records together with detailed numerical simulations have refined our understanding of past geological and climatic changes in Africa. To date, these important advances have not been reviewed within a common framework. Here, we critically review and synthesize African climate, tectonics and terrestrial biodiversity evolution throughout the Cenozoic to the mid-Pleistocene, drawing on recent advances in Earth and life sciences. We first review six major geo-climatic periods defining tropical African biodiversity diversification by synthesizing 89 dated molecular phylogeny studies. Two major geo-climatic factors impacting the diversification of the sub-Saharan biota are highlighted. First, Africa underwent numerous climatic fluctuations at ancient and more recent timescales, with tectonic, greenhouse gas, and orbital forcing stimulating diversification. Second, increased aridification since the Late Eocene led to important extinction events, but also provided unique diversification opportunities shaping the current tropical African biodiversity landscape. We then review diversification studies of tropical terrestrial animal and plant clades and discuss three major models of speciation: (i) geographic speciation via vicariance (allopatry); (ii) ecological speciation impacted by climate and geological changes, and (iii) genomic speciation via genome duplication. Geographic speciation has been the most widely documented to date and is a common speciation model across tropical Africa. We conclude with four important challenges faced by tropical African biodiversity research: (i) to increase knowledge by gathering basic and fundamental biodiversity information; (ii) to improve modelling of African geophysical evolution throughout the Cenozoic via better constraints and downscaling approaches; (iii) to increase the precision of phylogenetic reconstruction and molecular dating of tropical African clades by using next generation sequencing approaches together with better fossil calibrations; (iv) finally, as done here, to integrate data better from Earth and life sciences by focusing on the interdisciplinary study of the evolution of tropical African biodiversity in a wider geodiversity context.
热带非洲拥有令人惊叹的生物多样性，存在于各种生态系统中。过去的气候变化和地质事件影响了生物多样性的进化和多样化。在过去的二十年中，已经发表了大约 90 篇有关不同动植物类群的有日期分子系统发育的研究，这使得人们对热带非洲生物多样性的多样化和物种形成过程有了更多的了解。与此同时，扩展的地质和古气候记录以及详细的数值模拟也使我们对非洲过去的地质和气候变化有了更深入的了解。迄今为止，这些重要的进展尚未在一个共同的框架内进行综述。在这里，我们批判性地回顾和综合了整个新生代到中更新世期间非洲气候、构造和陆地生物多样性的演化，借鉴了地球科学和生命科学的最新进展。我们首先通过综合 89 项有日期分子系统发育研究，回顾了定义热带非洲生物多样性多样化的六个主要地理气候时期。强调了影响撒哈拉以南生物多样性多样化的两个主要地理气候因素。首先，非洲在古代和近代经历了多次气候波动，构造、温室气体和轨道强迫刺激了多样化。其次，晚始新世以来的干旱化加剧导致了重要的灭绝事件，但也为塑造当前热带非洲生物多样性景观提供了独特的多样化机会。然后，我们回顾了热带陆地动植物类群的多样化研究，并讨论了三种主要的物种形成模式：（i）通过隔离（异地）形成的地理物种形成；（ii）受气候和地质变化影响的生态物种形成；（iii）通过基因组复制形成的基因组物种形成。地理物种形成是迄今为止最广泛记录的物种形成模式，也是热带非洲的一种常见物种形成模式。最后，我们提出了热带非洲生物多样性研究面临的四个重要挑战：（i）通过收集基本和基础的生物多样性信息来增加知识；（ii）通过更好的约束和降尺度方法来改进整个新生代非洲地球物理演化的建模；（iii）通过使用下一代测序方法并结合更好的化石校准，提高热带非洲类群的系统发育重建和分子定年的精度；（iv）最后，像这里一样，通过关注热带非洲生物多样性在更广泛的地球多样性背景下的演化的跨学科研究，更好地整合来自地球科学和生命科学的数据。
