Yuan N, Comes H P, Cao Y N, Guo R, Zhang Y H, Qiu Y X
Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, Department of Ecology, College of Life Sciences, Zhejiang University, Hangzhou, China.
Department of Organismic Biology, Salzburg University, Salzburg, Austria.
Heredity (Edinb). 2015 Jun;114(6):544-51. doi: 10.1038/hdy.2014.114. Epub 2014 Dec 17.
Elucidating the demographic and landscape features that determine the genetic effects of habitat fragmentation has become fundamental to research in conservation and evolutionary biology. Land-bridge islands provide ideal study areas for investigating the genetic effects of habitat fragmentation at different temporal and spatial scales. In this context, we compared patterns of nuclear microsatellite variation between insular populations of a shrub of evergreen broad-leaved forest, Loropetalum chinense, from the artificially created Thousand-Island Lake (TIL) and the Holocene-dated Zhoushan Archipelago of Southeast China. Populations from the TIL region harboured higher levels of genetic diversity than those from the Zhoushan Archipelago, but these differences were not significant. There was no correlation between genetic diversity and most island features, excepting a negative effect of mainland-island distance on allelic richness and expected heterozygosity in the Zhoushan Archipelago. In general, levels of gene flow among island populations were moderate to high, and tests of alternative models of population history strongly favoured a gene flow-drift model over a pure drift model in each region. In sum, our results showed no obvious genetic effects of habitat fragmentation due to recent (artificial) or past (natural) island formation. Rather, they highlight the importance of gene flow (most likely via seed) in maintaining genetic variation and preventing inter-population differentiation in the face of habitat 'insularization' at different temporal and spatial scales.
阐明决定栖息地破碎化遗传效应的人口统计学和景观特征，已成为保护生物学和进化生物学研究的基础。陆桥岛屿为研究不同时空尺度下栖息地破碎化的遗传效应提供了理想的研究区域。在此背景下，我们比较了来自人工形成的千岛湖（TIL）和中国东南部全新世时期的舟山群岛的常绿阔叶林灌木檵木的岛屿种群之间的核微卫星变异模式。TIL地区的种群比舟山群岛的种群具有更高水平的遗传多样性，但这些差异并不显著。除了舟山群岛中大陆与岛屿的距离对等位基因丰富度和预期杂合度有负面影响外，遗传多样性与大多数岛屿特征之间没有相关性。总体而言，岛屿种群之间的基因流水平为中度到高度，并且对种群历史替代模型的检验强烈支持每个区域的基因流-漂变模型而非纯漂变模型。总之，我们的结果表明，近期（人工）或过去（自然）岛屿形成导致的栖息地破碎化没有明显的遗传效应。相反，它们强调了基因流（最有可能通过种子）在维持遗传变异和防止不同时空尺度下栖息地“岛屿化”过程中种群间分化方面的重要性。
