Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, 3101 Valley Life Sciences Building, Berkeley, CA 94720-3160, USA.
Mol Ecol. 2013 Mar;22(6):1650-65. doi: 10.1111/mec.12196. Epub 2013 Feb 4.
Understanding the biotic consequences of Pleistocene range shifts and fragmentation remains a fundamental goal in historical biogeography and evolutionary biology. Here, we combine species distribution models (SDM) from the present and two late Quaternary time periods with multilocus genetic data (mitochondrial DNA and microsatellites) to evaluate the effect of climate-induced habitat shifts on population genetic structure in the Large-blotched Ensatina (Ensatina eschscholtzii klauberi), a plethodontid salamander endemic to middle and high-elevation conifer forest in the Transverse and Peninsular Ranges of southern California and northern Baja California. A composite SDM representing the range through time predicts two disjunct refugia, one in southern California encompassing the core of the species range and the other in the Sierra San Pedro Mártir of northern Baja California at the southern limit of the species range. Based on our spatial model, we would expect a pattern of high connectivity among populations within the northern refugium and, conversely, a pattern of isolation due to long-term persistence of the Sierra San Pedro Mártir population. Our genetic results are consistent with these predictions based on the hypothetical refugia in that (i) historical measures of population connectivity among stable areas are correlated with gene flow estimates; and (ii) there is strong geographical structure between separate refugia. These results provide evidence for the role of recent climatic change in shaping patterns of population persistence and connectivity within the Transverse and Peninsular Ranges, an evolutionary hotspot.
了解更新世范围转移和碎裂的生物后果仍然是历史生物地理学和进化生物学的基本目标。在这里，我们结合了现在和两个晚第四纪时期的物种分布模型（SDM）以及多基因遗传数据（线粒体 DNA 和微卫星），以评估气候诱导的生境变化对大斑点蝾螈（Ensatina eschscholtzii klauberi）种群遗传结构的影响，这是一种生活在南加州横断山脉和半岛山脉中、海拔较高的针叶林的有肺螈科蝾螈，也是北下加利福尼亚北部的特有物种。一个代表整个时期范围的综合 SDM 预测了两个不连续的避难所，一个在南加州，包含了该物种核心分布区，另一个在北下加利福尼亚的圣佩德罗·马尔蒂尔山脉，位于该物种分布范围的南端。基于我们的空间模型，我们预计在北部避难所内的种群之间会有高度的连通性，而相反，由于圣佩德罗·马尔蒂尔山脉种群的长期存在，会出现隔离的模式。我们的遗传结果与基于假设避难所的这些预测是一致的，即：（i）稳定区域之间的种群连通性的历史测量与基因流动估计相关；（ii）在不同的避难所之间存在强烈的地理结构。这些结果为近期气候变化在塑造横断山脉和半岛山脉内的种群持续和连通模式方面的作用提供了证据，这是一个进化热点。
