Department of Integrative Ecology, Estación Biológica de Doñana (EBD-CSIC), Seville, Spain.
Department of Ecology, Environment and Evolution, LaTrobe University, Melbourne, Vic., Australia.
J Evol Biol. 2018 Aug;31(8):1204-1215. doi: 10.1111/jeb.13297. Epub 2018 Jun 14.
The progressive expansion of the Australian arid zone during the last 20 Ma appears to have spurred the diversification of several families of plants, vertebrates and invertebrates, yet such taxonomic groups appear to show limited niche radiation. Here, we test whether speciation is associated with niche conservatism (constraints on ecological divergence) or niche divergence in a tribe of marsupial mice (Sminthopsini; 23 taxa) that includes the most speciose genus of living dasyurids, the sminthopsins. To that end, we integrated phylogenetic data with ecological niche modelling, to enable us to reconstruct the evolution of climatic suitability within Sminthopsini. Niche overlap among species was low-moderate (but generally higher than expected given environmental background similarity), and the degree of phylogenetic clustering increased with aridity. Climatic niche reconstruction illustrates that there has been little apparent evolution of climatic tolerance within clades. Accordingly, climatic disparity tends to be accumulated among clades, suggesting considerable niche conservatism. Our results also indicate that evolution of climatic tolerances has been heterogeneous across different dimensions of climate (temperature vs. precipitation) and across phylogenetic clusters (Sminthopsis murina group vs. other groups). Although some results point to the existence of shifts in climatic niches during the speciation of sminthopsins, our study provides evidence for substantial phylogenetic niche conservatism in the group. We conclude that niche diversification had a low impact on the speciation of this tribe of small, but highly mobile marsupials.
在过去的 2000 万年中，澳大利亚干旱区的不断扩张似乎刺激了几个植物科、脊椎动物和无脊椎动物的多样化，但这些分类群似乎表现出有限的生态位辐射。在这里，我们测试了在一个有袋类老鼠的部落（Sminthopsini；23 个分类单元）中，物种形成是否与生态位保守（对生态差异的限制）或生态位差异有关，该部落包括最具生物多样性的现存袋鼬属，即 sminthopsins。为此，我们将系统发育数据与生态位模型相结合，以便能够重建 Sminthopsini 内部气候适宜性的进化。物种之间的生态位重叠程度较低（但通常高于环境背景相似性的预期），并且系统发育聚类的程度随着干旱度的增加而增加。气候生态位重建表明，在进化枝内，气候耐受性几乎没有明显的进化。因此，气候差异往往在进化枝之间积累，表明存在相当大的生态位保守性。我们的结果还表明，在不同的气候维度（温度与降水）和不同的系统发育聚类（Sminthopsis murina 组与其他组）中，气候耐受性的进化是不均匀的。尽管一些结果表明，在 sminthopsins 的物种形成过程中，气候生态位发生了变化，但我们的研究为该小而高度移动的有袋类动物群的系统发育生态位保守性提供了证据。我们得出的结论是，生态位多样化对这个小而高度移动的有袋类动物部落的物种形成影响不大。
