Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing, 100101, People's Republic of China.
International College, University of Chinese Academy of Sciences, Beijing, People's Republic of China.
BMC Evol Biol. 2019 Jun 1;19(1):113. doi: 10.1186/s12862-019-1426-z.
The Taklimakan Desert in China is characterized by unique geological and historical dynamics and endemic flora and fauna, but the influence of historical climate oscillations on the evolutionary history of endemic animals is poorly understood. Lepus yarkandensis is an oases-dependent Near Threatened species that lives in fragmented oasis habitats in the Taklimakan Desert, China. We investigated the geological and climatic impacts on its geographical differentiation, demographic history and influence of Pleistocene glacial-interglacial cycles on the evolutionary history of L. yarkandensis. Further, studied the impact of climatic oscillation based modification on phylogeography, distribution and diversification pattern of Yarkand hare by using Cytb (1140 bp), MGF (592 bp) and SPTBN1 (619 bp) markers. Ecological niche modeling (ENM) revealed the evolutionary history of this species in response to climate change during the Quaternary. Paleodistribution modeling was used to identify putative refugia and estimate their historical distributions.
Both historical demographic analyses and climatic niche modeling revealed strong effects of glacial climate changes, suggesting recurrent range contractions and expansions. The EBSP results indicated clear population expansion of L. yarkandensis since the Pleistocene. In the "early Pleistocene", the demographic expansion continued from 0.83 MYA to the last glacial period. The ENM analysis supported a wide distribution of Lepus yarkandensis at high altitudes during the last interglacial (LIG) period. During the last glacial maximum (LGM), the suitable climate was reduced and restricted to the western part of the Taklimakan Desert.
Inland aridification, oasis evolution and river flow played major roles in the population differentiation and demographic history of Yarkand hares. Historically, the large, continuous oases in the Taklimakan Desert contained a viable and unique population of L. yarkandensis. The fragmented desert environment might have caused low gene flow between individuals or groups, thus leading to predominant genetic differentiation. The Pleistocene climatic cycles triggered the diversification and expansion of this species during cold and warm periods, respectively, leading to multiple colonization events within the Taklimakan Desert. These events might be due to the expansion of the Taklimakan Desert during the Middle Pleistocene. Yarkand hare previously occupied vast areas at low and intermediate altitudes in Xinjiang, Gansu, Shanxi, Henan and Shaanxi Provinces in China. The past aridification, climate change-induced oasis modifications, changes in river volumes and flow directions, and human activities all affected the population demography and phylogeography of the Yarkand hare.
中国的塔克拉玛干沙漠具有独特的地质和历史动态以及特有动植物区系，但历史气候波动对特有动物进化历史的影响仍知之甚少。塔里木兔是一种依赖绿洲的近危物种，生活在中国塔克拉玛干沙漠的碎片化绿洲栖息地中。我们研究了地质和气候对其地理分化、种群历史以及更新世冰期-间冰期循环对塔里木兔进化历史的影响。此外，我们还利用 Cytb（1140bp）、MGF（592bp）和 SPTBN1（619bp）标记，研究了气候波动对其系统地理学、分布和多样化模式的影响。生态位模型（ENM）揭示了该物种在第四纪气候变化下的进化历史。古分布模型用于识别可能的避难所并估计其历史分布。
历史种群动态分析和气候生态位建模都显示出冰期气候变化的强烈影响，表明其范围反复收缩和扩张。EBSP 结果表明，自更新世以来，塔里木兔种群明显扩张。在“早更新世”，从 0.83 百万年前到末次冰期，种群持续扩张。ENM 分析支持末次间冰期（LIG）期间塔里木兔在高海拔地区的广泛分布。末次冰盛期（LGM）期间，适宜气候减少，仅限于塔克拉玛干沙漠西部。
内陆干旱化、绿洲演化和河流流量在塔里木兔种群分化和种群历史中发挥了重要作用。历史上，塔克拉玛干沙漠中较大的连续绿洲中存在着一个可行的、独特的塔里木兔种群。碎片化的沙漠环境可能导致个体或群体之间的基因流较低，从而导致主要的遗传分化。更新世气候循环在冷暖和温暖时期分别触发了该物种的多样化和扩张，导致在塔克拉玛干沙漠内部发生了多次定居事件。这些事件可能是由于中更新世塔克拉玛干沙漠的扩张。塔里木兔曾在中国新疆、甘肃、山西、河南和陕西等省的低海拔和中海拔地区广泛分布。过去的干旱化、气候变化引起的绿洲变化、河流径流量和流向的变化以及人类活动都影响了塔里木兔的种群动态和系统地理学。
