Institute of Botany, University of Liège, Liège, Belgium.
PLoS One. 2013;8(2):e55648. doi: 10.1371/journal.pone.0055648. Epub 2013 Feb 11.
The definition of biogeographic regions provides a fundamental framework for a range of basic and applied questions in biogeography, evolutionary biology, systematics and conservation. Previous research suggested that environmental forcing results in highly congruent regionalization patterns across taxa, but that the size and number of regions depends on the dispersal ability of the taxa considered. We produced a biogeographic regionalization of European bryophytes and hypothesized that (1) regions defined for bryophytes would differ from those defined for other taxa due to the highly specific eco-physiology of the group and (2) their high dispersal ability would result in the resolution of few, large regions. Species distributions were recorded using 10,000 km2 MGRS pixels. Because of the lack of data across large portions of the area, species distribution models employing macroclimatic variables as predictors were used to determine the potential composition of empty pixels. K-means clustering analyses of the pixels based on their potential species composition were employed to define biogeographic regions. The optimal number of regions was determined by v-fold cross-validation and Moran's I statistic. The spatial congruence of the regions identified from their potential bryophyte assemblages with large-scale vegetation patterns is at odds with our primary hypothesis. This reinforces the notion that post-glacial migration patterns might have been much more similar in bryophytes and vascular plants than previously thought. The substantially lower optimal number of clusters and the absence of nested patterns within the main biogeographic regions, as compared to identical analyses in vascular plants, support our second hypothesis. The modelling approach implemented here is, however, based on many assumptions that are discussed but can only be tested when additional data on species distributions become available, highlighting the substantial importance of developing integrated mapping projects for all taxa in key biogeographically areas of Europe, and the Mediterranean peninsulas in particular.
生物地理区域的定义为生物地理学、进化生物学、系统学和保护学中的一系列基础和应用问题提供了一个基本框架。先前的研究表明，环境胁迫导致分类群之间高度一致的区域划分模式，但区域的大小和数量取决于所考虑分类群的扩散能力。我们对欧洲苔藓植物进行了生物地理区域化，并提出假设：（1）由于该类群具有高度特异的生态生理学，因此为苔藓植物定义的区域将与为其他分类群定义的区域不同；（2）由于其高扩散能力，将导致很少、很大的区域得到解决。使用 10000km2MGRS 像素记录物种分布。由于该地区大部分地区缺乏数据，因此使用基于宏气候变量作为预测因子的物种分布模型来确定空像素的潜在组成。基于其潜在物种组成，对像素进行 K-均值聚类分析，以定义生物地理区域。通过 v 倍交叉验证和 Moran's I 统计确定最佳区域数量。从潜在苔藓植物组合中识别出的区域与大尺度植被模式的空间一致性与我们的主要假设不一致。这再次强调了这样一种观点，即与以前的想法相比，冰川后迁移模式在苔藓植物和维管植物中可能更为相似。与维管植物的相同分析相比，最佳聚类数量明显减少，主要生物地理区域内没有嵌套模式，这支持了我们的第二个假设。然而，这里实施的建模方法基于许多假设，这些假设已被讨论，但只有在获得更多有关物种分布的数据时才能进行测试，这突出了在欧洲关键生物地理区域，特别是在地中海半岛，为所有分类群制定综合绘图项目的重要性。
