School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China.
State Key Laboratory of Plant Diversity and Specialty Crops, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Commun Biol. 2024 Aug 16;7(1):1002. doi: 10.1038/s42003-024-06687-4.
The processes of forming lineages undergoing widespread radiations remain a knowledge gap that is fundamental to our understanding of the geographic distributions of species. Although early studies emphasized the importance of dispersal ability and historical migration events, key innovations that promote rapid diversification and/or adaptation to new habitats may also strongly influence distribution ranges. Juniperus is the second largest genus of conifers and is widely distributed throughout the Northern Hemisphere. Here, we used phylogenetic, phenotypic, and climatic data to investigate the contributions of these processes to the wide distribution and rapid diversification of Juniperus. Combining a time-scaled phylogeny and macroevolutionary theory, we show that the key innovations of berry-like seed cones and dioecy promoted the rapid diversification of Juniperus and that increased dispersal ability promoted allopatric speciation. Ecological niches had significant divergence among different clades of Juniperus. Biogeographic results supported multiple long-distance dispersal events and niche variation that contributed to the modern range of Juniperus, while both phenotypic adaptation and ecological opportunity probably drove its distribution range. Our findings suggest that the current widespread distribution is likely the result of significant divergence driven by niche variation in which ecological opportunities from key innovation and phenotypic divergence.
形成广泛辐射的谱系的过程仍然是一个知识空白，这对于我们理解物种的地理分布至关重要。尽管早期的研究强调了扩散能力和历史迁移事件的重要性，但促进快速多样化和/或适应新栖息地的关键创新也可能强烈影响分布范围。刺柏是第二大针叶树属，广泛分布于北半球。在这里，我们使用系统发育、表型和气候数据来研究这些过程对刺柏广泛分布和快速多样化的贡献。通过结合时间尺度的系统发育和宏观进化理论，我们表明，浆果状种子球果和雌雄异株的关键创新促进了刺柏的快速多样化，而扩散能力的提高促进了异域物种形成。不同刺柏类群的生态位有明显的差异。生物地理结果支持了多次长距离扩散事件和有助于现代刺柏分布范围的生态位变化，而表型适应和生态机会可能都推动了其分布范围。我们的研究结果表明，当前广泛的分布可能是由生态位变化驱动的，而关键创新和表型分化带来的生态机会促进了这一变化。
