Evidence of morphometric differentiation among Antarctic moss populations as a response to local microenvironment

ABSTRACTStudies on phenotypic variation among populations growing in different microenvironments may provide information about plasticity related to environmental pressures, and thus help to elucidate the potential evolutionary forces contributing to the origin and maintenance of diversity in any region. In this study we investigate morphometric variation on a small geographic scale for three species of Antarctic mosses. All species revealed significant differentiation among populations for all evaluated traits. The comparison of morphometric measures of populations of Polytrichum juniperinumfrom Nelson Island and from southern Brazil suggests that the effects of a small geographic scale in Antarctica are the same as a large geographic scale in environments where the climate is more homogeneous and microhabitats have minor influence on vegetation. However, further investigations over a larger area, evaluating more species, and using controlled garden experiments are recommended in order to evaluate the capacity for plasticity of moss species in different climatic conditions and on different geographic scales.摘要 针对生长于不同微环境的种群间表型变异展开的研究，可揭示与环境压力相关的表型可塑性相关信息，进而有助于阐明驱动任一区域生物多样性起源与维持的潜在进化力量。本研究针对三种南极苔藓，开展小地理尺度下的形态计量变异分析。所有供试物种的全部评估性状均显示种群间存在显著分化。对纳尔逊岛（Nelson Island）与巴西南部种群的桧叶金发藓（Polytrichum juniperinum）形态计量指标进行比较后发现：南极地区的小地理尺度效应，与气候更均质、微生境对植被影响较弱的环境中的大地理尺度效应并无二致。不过，为评估苔藓物种在不同气候条件与不同地理尺度下的可塑性能力，仍建议开展更大范围的调查，纳入更多供试物种，并采用受控园艺实验进行验证。