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 as...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.展开更多
首先针对两重化、双两重化、三重化以及双三重化这四种系统架构下的安全仪表系统的要求时平均危险失效率(Average Probability of Dangerous Failure on Demand,PFDavg)、误跳车率(Spurious Trip Rate,STR)以及生命周期成本(Life Circle...首先针对两重化、双两重化、三重化以及双三重化这四种系统架构下的安全仪表系统的要求时平均危险失效率(Average Probability of Dangerous Failure on Demand,PFDavg)、误跳车率(Spurious Trip Rate,STR)以及生命周期成本(Life Circle Cost,LCC)进行多目标模型分析。并结合工控行业实际情况,分析单重架构Moo N及双重架构2×Moo N的各指标的差异,结果表明两重化架构下的误跳车率是其他三种架构下的近100倍。基于此再进一步分析现场需要的备件数量,以及在双两重化和三重化架构下生命周期成本。展开更多
基金supported by the National Natural Science Foundation of China(31500335)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB31000000).
文摘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.
文摘首先针对两重化、双两重化、三重化以及双三重化这四种系统架构下的安全仪表系统的要求时平均危险失效率(Average Probability of Dangerous Failure on Demand,PFDavg)、误跳车率(Spurious Trip Rate,STR)以及生命周期成本(Life Circle Cost,LCC)进行多目标模型分析。并结合工控行业实际情况,分析单重架构Moo N及双重架构2×Moo N的各指标的差异,结果表明两重化架构下的误跳车率是其他三种架构下的近100倍。基于此再进一步分析现场需要的备件数量,以及在双两重化和三重化架构下生命周期成本。
