Palma R Eduardo, Gutiérrez-Tapia Pablo, González Juan F, Boric-Bargetto Dusan, Torres-Pérez Fernando
Departamento de Ecología, Pontificia Universidad Católica de Chile, Santiago, Chile.
Laboratorio de Ecología y Biodiversidad, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile.
PLoS One. 2017 Jul 3;12(7):e0180231. doi: 10.1371/journal.pone.0180231. eCollection 2017.
We evaluated if two sigmodontine rodent taxa (Abrothrix olivacea and Phyllotis darwini) from the Andes and Coastal mountaintops of central Chile, experienced distributional shifts due to altitudinal movements of habitat and climate change during and after the Last Glacial Maximum (LGM). We tested the hypothesis that during LGM populations of both species experienced altitudinal shifts from the Andes to the lowlands and the coastal Cordillera, and then range retractions during interglacial towards higher elevations in the Andes. These distributional shifts may have left remnants populations on the mountaintops. We evaluated the occurrence of intraspecific lineages for each species, to construct distribution models at LGM and at present, as extreme climatic conditions for each lineage. Differences in distribution between extreme climatic conditions were interpreted as post-glacial distributional shifts. Abrothrix olivacea displayed a lineage with shared sequences between both mountain systems, whereas a second lineage was restricted to the Andes. A similar scenario of panmictic unit in the past was recovered for A. olivacea in the Andes, along with an additional unit that included localities from the rest of its distribution. For P. darwini, both lineages recovered were distributed in coastal and Andean mountain ranges at present as well, and structuring analyses for this species recovered coastal and Andean localities as panmictic units in the past. Niche modeling depicted differential postglacial expansions in the recovered lineages. Results suggest that historical events such as LGM triggered the descending of populations to Andean refuge areas (one of the A. olivacea's lineages), to the lowlands, and to the coastal Cordillera. Backward movements of populations after glacial retreats may have left isolates on mountaintops of the coastal Cordillera, suggesting that current species distribution would be the outcome of climate change and habitat reconfiguration after LGM.
我们评估了来自智利中部安第斯山脉和沿海山顶的两个稻鼠科啮齿动物类群（橄榄色南美稻鼠和达尔文叶耳鼠），在末次盛冰期（LGM）期间及之后，是否因栖息地的海拔变动和气候变化而经历了分布变化。我们检验了这样一个假设：在末次盛冰期，这两个物种的种群都经历了从安第斯山脉向低地和沿海山脉的海拔迁移，然后在冰期向安第斯山脉更高海拔地区的范围收缩。这些分布变化可能在山顶留下了残余种群。我们评估了每个物种种内谱系的出现情况，以构建末次盛冰期和当前的分布模型，作为每个谱系的极端气候条件。极端气候条件下分布的差异被解释为冰后期的分布变化。橄榄色南美稻鼠显示出一个在两个山脉系统之间具有共享序列的谱系，而另一个谱系则局限于安第斯山脉。在安第斯山脉，过去橄榄色南美稻鼠的类似泛交单元的情况被恢复，同时还恢复了一个额外的单元，该单元包括其分布区其他地方的地点。对于达尔文叶耳鼠，目前恢复的两个谱系也分布在沿海和安第斯山脉，对该物种的结构分析恢复了沿海和安第斯地区过去作为泛交单元的情况。生态位建模描绘了恢复谱系中不同的冰后期扩张情况。结果表明，末次盛冰期等历史事件引发了种群向安第斯避难区（橄榄色南美稻鼠的一个谱系）、低地和沿海山脉的下降。冰川消退后种群的向后迁移可能在沿海山脉的山顶留下了孤立种群，这表明当前物种分布是末次盛冰期后气候变化和栖息地重新配置的结果。
