Modeled trajectories of the Mediterranean squamates

Mediterranean islands have a high diversity of squamates, although they are unevenly distributed. This variability in the composition of the reptile assemblages across islands may have been influenced by differences in the colonization abilities of these species. To evaluate the dispersal capacities of squamate species, we modeled their sea routes using cost surface models. We estimated the effects of some life-history traits and the phylogenetic signal in the characteristics of the modeled dispersal paths. We hypothesized that a significant phylogenetic signal should be present if the dispersal ability is enhanced by traits shared among evolutionarily related species. The results showed that no phylogenetic signal was present in the characteristics of the dispersal paths (i.e., in the distance traveled/bypassed sea depth). Thus, no superior island-colonizer lineages were detected in Mediterranean Squamata. However, our analyses also revealed that small-sized lizards were superior to other groups of squamates at dispersing over long distances on the sea.Mediterranean islands have a high diversity of squamates, although they are unevenly distributed. This variability in the composition of the reptile assemblages across islands may have been influenced by differences in the colonization abilities of these species. To evaluate the dispersal capacities of squamate species, we modeled their sea routes using cost surface models. We estimated the effects of some life-history traits and the phylogenetic signal in the characteristics of the modeled dispersal paths. We hypothesized that a significant phylogenetic signal should be present if the dispersal ability is enhanced by traits shared among evolutionarily related species. The results showed that no phylogenetic signal was present in the characteristics of the dispersal paths (i.e., in the distance traveled/bypassed sea depth). Thus, no superior island-colonizer lineages were detected in Mediterranean Squamata. However, our analyses also revealed that small-sized lizards were superior to other groups of squamates at dispersing over long distances on the sea.

地中海诸岛的有鳞目（Squamata）物种多样性颇高，但类群分布并不均匀。诸岛间爬行动物类群组成的异质性，或许受这些物种岛屿定殖能力差异的影响。为评估有鳞目物种的跨海扩散能力，本研究采用成本表面模型（cost surface models）对其扩散路径进行建模。我们同时估算了部分生活史性状（life-history traits）对扩散的影响，以及建模所得扩散路径特征中的系统发育信号（phylogenetic signal）。我们提出假说：若演化亲缘关系较近的物种所共有的性状可提升其扩散能力，则扩散路径特征中应存在显著的系统发育信号。研究结果显示，扩散路径的特征（即跨海行进距离/绕行海域水深）中并未检测到系统发育信号。因此，在地中海有鳞目类群中未发现具备卓越岛屿定殖能力的演化支系。但本研究的分析同时表明，小型蜥蜴类群的跨海长距离扩散能力优于其他有鳞目类群。