Departamento de Botânica, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Laboratório de Sistemática Vegetal, Departamento de Botânica, Universidade de São Paulo, São Paulo, SP, Brazil.
Mol Phylogenet Evol. 2020 Jul;148:106815. doi: 10.1016/j.ympev.2020.106815. Epub 2020 Apr 9.
Species of plants with different life history strategies may differ in their seed dispersal mechanisms, impacting their distribution and diversification patterns. Shorter or longer distance dispersal is favored by different dispersal modes, facilitating (or constraining) population isolation, which can, in turn, impact speciation and species range sizes. While these associations are intuitive, few studies have explicitly tested these hypotheses for large clades of angiosperms. The plant family Melastomataceae is found on disparate habitats with different dispersal modes, representing a good model to address these questions. In this study, we reconstruct the phylogeny of Melastomataceae and gather data on their dispersal mode and range size to test the impact of dispersal mode on diversification and range size evolution. We found that abiotic dispersal is ancestral in the family, while biotic dispersal evolved multiple times. Species richness distribution is very similar across dispersal modes, although abiotically dispersed species tend to be relatively more diverse in seasonal environments. Range sizes across dispersal modes are not significantly different, although biotically dispersed species have slightly wider distributions. Model comparisons indicate that factors other than dispersal mode might have driven diversification heterogeneity. We did not find evidence for the role of dispersal mode driving diversification rates or range size in the Melastomataceae, suggesting a complex macroevolutionary scenario for this diverse angiosperm family. The bulk of changes to biotic dispersal coinciding with an increase in passerine diversification suggests a possible "past" key innovation in Melastomataceae. Future studies should investigate the role of other diversification drivers in the family and the relatively higher diversity of abiotically dispersed species in open habitats.
具有不同生活史策略的植物物种可能在其种子扩散机制上存在差异,这影响了它们的分布和多样化模式。不同的扩散模式有利于较短或较长距离的扩散,从而促进(或限制)种群隔离,这反过来又会影响物种形成和物种范围大小。虽然这些关联是直观的,但很少有研究明确测试过大角果科被子植物类群的这些假设。野牡丹科植物分布在具有不同扩散模式的不同栖息地,是解决这些问题的良好模型。在这项研究中,我们重建了野牡丹科的系统发育,并收集了它们的扩散模式和范围大小的数据,以测试扩散模式对多样化和范围大小进化的影响。我们发现,非生物扩散是该科的祖征,而生物扩散则多次进化。尽管在季节性环境中,无生命扩散的物种往往相对更加多样化,但不同扩散模式的物种丰富度分布非常相似。不同扩散模式的分布范围没有显著差异,尽管生物扩散的物种分布范围稍宽。模型比较表明,除了扩散模式之外,其他因素可能导致了多样化的异质性。我们没有发现扩散模式在驱动多样化率或野牡丹科范围大小方面的作用的证据,这表明对于这个多样化的被子植物科,存在一个复杂的宏观进化情景。与雀形目鸟类多样化增加同时发生的生物扩散的大部分变化表明,野牡丹科可能存在一个“过去”的关键创新。未来的研究应该调查该科中其他多样化驱动因素的作用,以及无生命扩散物种在开阔栖息地中相对较高的多样性。