山西陵川南方红豆杉自然保护区鹅耳枥植物群落谱系结构特征

Phylogenetic structure characteristics of Carpinus turczaninowii community in Taxus chinensis Nature Reserve in Lingchuan,Shanxi Province

分析植物群落谱系结构,可以探究乔木层、灌木层和草本层物种对环境变化的响应情况。以山西陵川南方红豆杉自然保护区鹅耳枥群落为研究对象,采用样方法,分别从不同径级和不同坡向对鹅耳枥群落净谱系亲缘关系指数(Net relatedness index,NRI)和净最近种间亲缘关系指数(Nearest taxon index,NTI)进行研究,探讨了鹅耳枥群落沿着径级梯度形成群落谱系结构特征,进而分析了鹅耳枥群落构建的历史进程。结果表明:(1)该保护区鹅耳枥群落乔木层(26种)、灌木层(32种)和草本层(39种)谱系结构树可分为5个类群、5个类群和4个类群;乔木层(86.67%的样地,下同)和灌木层(73.33%)物种群落谱系结构呈谱系发散格局(NRI<0,NTI<0),但草本层(86.67%)物种群落谱系结构呈谱系聚集格局(NRI>0,NTI>0)。(2)鹅耳枥群落乔木层中,DBH在Ⅰ级至Ⅱ级间,NRI指数随着DBH的增大而减小,NTI指数随着DBH的增大而增大;在Ⅱ级至Ⅴ级之间,随着植物DBH增大NRI指数和NTI指数值均呈下降趋势;而且在不同DBH水平上群落NRI和NTI指数均差异显著(P<0.05),说明随着径级的增大,群落谱系结构由谱系聚集变为谱系发散。(3)灌木层物种谱系结构在阴坡和阳坡均呈聚集型,乔木层阴坡物种的谱系结构呈发散型(NRI<0,NTI<0),乔木层阳坡和草本层阴阳坡群落均无法判定群落谱系结构是聚集还是发散。

By analyzing the phylogenetic structure of plant community,the response of species to environmental changes in tree layer,shrub layer,and herbaceous layer can be explored.Carpinus turczaninowii community in Taxus chinensis Nature Reserve in Lingchuan,Shanxi province were surveyed and compared.The net relatedness index(NRI)and nearest taxon index(NTI)of Carpinus turczaninowii community from different spatial scale and different sloping directions were studied by the method of sampling analysis.The phylogenetic structure characteristics of Carpinus turczaninowii community formed along the spatial scale gradient were discussed and the historical process of the construction of Carpinus turczaninowii community was analyzed.The results showed that:(1)the phylogenetic tree of Carpinus turczaninowii community in these reserve arbor layer(26 species),shrub layer(32 species),and herbaceous layer(39 species)could be divided into 5 groups,5 groups,and 4 groups,respectively.Arbor layer(86.67%of the plot,the below is same)and shrub layer(73.33%)species community phylogenetic structure were phylogenetically overdispersed(NRI<0,NTI<0),but the herbaceous layer(86.67%)species community phylogenetic structure were phylogenetically clustered(NRI>0,NTI>0).(2)In the arbor layer of Carpinus turczaninowii community,from the first stage to the second stage,the NRI index decreased with the increasing of the diameter at byeast height(DBH),but the NTI index increased.From the second stage to the fifth stage,with the increasing of DBH,the NRI index and the NTI index showed a decreasing trend;at different DBH level,NRI and NTI index was significant difference(P<0.05).The results showed that the community phylogenetic structure changed from phylogenetic clustering to phylogenetic overdisperseding.(3)The species of shrub layer were phylogenetically clustered on the shady and sunny slopes.The species on the shady slope in arbor layer were phylogenetically overdispersed(NRI<0,NTI>0).The arbor layer on sunny slope and herbaceous layer on both shady and sunny slope community were unable to determine whether the phylogenetic structure of the community was clustered or overdispersed.