摘要
Aims Phylogenetic diversity metrics can discern the relative contributions of ecological and evolutionary processes associated with the assembly of plant communities.However,the magnitude of the potential variation associated with phylogenetic methodologies,and its effect on estimates of phylogenetic diversity,remains poorly understood.Here,we assess how sources of variation associated with estimates of phylogenetic diversity can pote ntially affect our understanding of plant community structure for a series of temperate forest plots in China.Methods In total,20 forest plots,comprising of 274 woody species and 581 herbaceous species,were surveyed and sampled along an elevational gradient of 2800 m on Taibai Mountain,China.We used multi-model inference to search for the most parsimonious relationship between estimates of phylogenetic diversity and each of four predictors(i.e.type of phylogenetic reconstruction method,phylogenetic diversity metric,woody or herbaceous growth form and elevation),and their pairwise interactions.Important Findings There was nosignificant difference in patterns of phylogenetic diversity when using synthesis-based vs.molecular-based phylogenetic methods.Results showed that elevation,the type of phylogenetic diversity metric,growth form and their interactions,accounted for>44% of the variance in our estimates of phylogenetic diversity.In general,phylogenetic diversity decreased with increasing elevation;however,the trend was weaker for herbaceous plants than for woody plants.Moreover,the three phylogenetic diversity metrics showed consistent patterns(i.e.clustered)across the elevational gradient for woody plants.For herbaceous plants,the mean pairwise distanee showed a random distribution over the gradient.These results suggest that a better understanding of temperate forest comunity structure can be obtained when estimates of phylogenetic diversity include methodological and environmental sources of variation.
系统发育多样性指数常被用作区分植物群落构建过程中生态和演化过程的相对作用。系统发育多样性格局的推断方法(如系统树的构建和不同的系统发育多样性指数)、演化历史(如生活型)以及环境梯度都可能影响系统发育多样性格局的估计值,进而可能影响我们对植物群落构建过程的认知。因此,有必要区分这些因素如何作用于系统发育多样性格局的估计值,但其相对重要性及其交互作用仍不清楚。本研究利用位于太白山北坡沿海拔分布的20个森林样地(整体高差2800 m左右)的野外调查数据,包括274种木本植物和581种草本植物。对于上述样地内所有植物,我们构建了当前广泛采用的合成树和分子树以比较系统树的构建,特别是合成树末端的多歧分支结构,及其对系统发育多样性格局估计值的可能影响。同时,我们计算了每个样地的3种不同的系统发育多样性指数,包括Faithl PD,平均成对距离(MPD)和平均最近类群距离(MNTD),并分别对木本和草本植物进行计算。多模型比较分析系统发育多样性格局的估计值与系统树重建方法、多样性指数、生活型、海拔及其交互作用的最简约关系。研究结果表明,基于合成树和分子树所得到的系统发育多样性格局之间没有显著差异。海拔和多样性指数与生活型在解释系统发育多样性格局方面存在强烈的交互作用,并且能够解释44%以上的变异。系统发育多样性格局的估计值总体随海拔升高而降低,但草本植物相比木本植物变化更平缓。对于木本植物,3种系统发育多样性指数表现出一致的海拔分布格局(即系统发育聚集),而草本植物的平均成对距离指数则表现为随机的海拔分布格局。因此,分析沿环境梯度的系统发育多样性格局需要考虑系统发育格局的推断方法和演化历史的影响,以帮助我们更好地理解植物群落的构建过程。
基金
supported by the National Natural Science Foundation of China(31500335)
the Strategic Priority Research Program of Chinese Academy of Sciences(XDB31000000).
