Laboratory of Molecular Systematics, Limnological Institute of the Siberian Branch of the Russian Academy of Sciences, Ulan-Batorskaya 3, 664033 Irkutsk, Russia.
BMC Evol Biol. 2010 Oct 23;10:320. doi: 10.1186/1471-2148-10-320.
While the impact of climate fluctuations on the demographic histories of species caused by changes in habitat availability is well studied, populations of species from systems without geographic isolation have received comparatively little attention. Using CO1 mitochondrial sequences, we analysed phylogeographic patterns and demographic histories of populations of five species (four gastropod and one amphipod species) co-occurring in the southwestern shore of Lake Baikal, an area where environmental oscillations have not resulted in geographical isolation of habitats.
Species with stronger habitat preferences (gastropods B. turriformis, B. carinata and B. carinatocostata) exhibit rather stable population sizes through their evolutionary history, and their phylogeographic pattern indicates moderate habitat fragmentation. Conversely, species without strong habitat preference (gastropod M. herderiana and amphipod G. fasciatus) exhibit haplotype networks with a very abundant and widespread central haplotype and a big number of singleton haplotypes, while their reconstructed demographic histories show a population expansion starting about 25-50 thousand years ago, a period marked by climate warming and increase in diatom abundance as inferred from bottom-lake sedimentary cores.
In agreement with previous studies, we found that species reacted differently to the same environmental changes. Our results highlight the important role of dispersal ability and degree of ecological specialization in defining a species' response to environmental changes.
虽然栖息地可利用性变化引起的气候波动对物种的种群历史产生的影响已得到充分研究，但来自没有地理隔离系统的物种的种群受到的关注相对较少。利用 CO1 线粒体序列，我们分析了共生于贝加尔湖西南岸的五个物种（四种腹足纲和一种端足纲物种）的系统地理格局和种群历史动态。在该地区，环境波动并未导致栖息地的地理隔离。
具有较强栖息地偏好的物种（腹足纲的 B. turriformis、B. carinata 和 B. carinatocostata）在其进化历史中表现出相对稳定的种群大小，其系统地理格局表明栖息地的中度片段化。相反，没有强烈栖息地偏好的物种（腹足纲的 M. herderiana 和端足纲的 G. fasciatus）表现出具有丰富且广泛的中心单倍型和大量单倍型的单倍型网络，而其重建的种群历史显示，种群扩张始于约 25-50 千年前，这一时期气候变暖，底湖沉积物核心推断出硅藻丰度增加。
与先前的研究一致，我们发现物种对相同的环境变化有不同的反应。我们的研究结果强调了扩散能力和生态专业化程度在决定物种对环境变化的响应中的重要作用。
