Qian Hong, Jin Yi
Research and Collections Center, Illinois State Museum, 1011 East Ash Street, Springfield, IL, 62703, USA.
Key Laboratory of State Forestry Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, Guizhou Normal University, Guiyang, 550025, China.
Plant Divers. 2020 Nov 28;43(4):255-263. doi: 10.1016/j.pld.2020.11.005. eCollection 2021 Aug.
Phylogenies are essential to studies investigating the effect of evolutionary history on assembly of species in ecological communities and geographical and ecological patterns of phylogenetic structure of species assemblages. Because phylogenies well resolved at the species level are lacking for many major groups of organisms such as vascular plants, researchers often generate a species-level phylogenies using a phylogeny well resolved at the genus level as a backbone and attaching species to their respective genera in the phylogeny as polytomies or by using a megaphylogeny well resolved at the genus level as a backbone and adding additional species to the megaphylogeny as polytomies of their respective genera. However, whether the result of a study using species-level phylogenies generated in these ways is robust, compared to that based on phylogenies fully resolved at the species level, has not been assessed. Here, we use 1093 angiosperm tree assemblages (each in a 110 × 110 km quadrat) in North America as a model system to address this question, by examining six commonly used metrics of phylogenetic structure (phylogenetic diversity and phylogenetic relatedness) and six climate variables commonly used in ecology. Our results showed that (1) the scores of phylogenetic metrics derived from species-level phylogenies resolved at the genus level with species being attached to their respective genera as polytomies are very strongly or perfectly correlated to those derived from a phylogeny fully resolved at the species level (the mean of correlation coefficients is 0.973), and (2) the relationships between the scores of phylogenetic metrics and climate variables are consistent between the two sets of analyses based on the two types of phylogeny. Our study suggests that using species-level phylogenies resolved at the genus level with species being attached to their genera as polytomies is appropriate in studies exploring patterns of phylogenetic structure of species in ecological communities across geographical and ecological gradients.
系统发育对于研究进化历史对生态群落中物种组装的影响以及物种组合的系统发育结构的地理和生态模式至关重要。由于许多主要生物类群（如维管植物）缺乏在物种水平上解析良好的系统发育树，研究人员通常使用在属水平上解析良好的系统发育树作为主干，并将物种以多歧分支的形式附着到其各自的属上，从而生成物种水平的系统发育树；或者使用在属水平上解析良好的超级系统发育树作为主干，并将其他物种以其各自属的多歧分支形式添加到超级系统发育树中。然而，与基于在物种水平上完全解析的系统发育树的研究结果相比，以这些方式生成的物种水平系统发育树的研究结果是否可靠尚未得到评估。在这里，我们使用北美1093个被子植物树组合（每个组合位于一个110×110平方公里的样方中）作为模型系统来解决这个问题，通过检查六个常用的系统发育结构指标（系统发育多样性和系统发育相关性）以及生态学中常用的六个气候变量。我们的结果表明：（1）从以多歧分支形式将物种附着到其各自属上的属水平解析的物种水平系统发育树得出的系统发育指标得分，与从在物种水平上完全解析的系统发育树得出的得分非常强或完全相关（相关系数的平均值为0.973）；（2）基于这两种系统发育树的两组分析中，系统发育指标得分与气候变量之间的关系是一致的。我们的研究表明，在探索跨地理和生态梯度的生态群落中物种系统发育结构模式的研究中，使用以多歧分支形式将物种附着到其属上的属水平解析的物种水平系统发育树是合适的。
