不同空间尺度西藏色季拉山急尖长苞冷杉 群落谱系结构特征. (Chinese)

We analyzed Lhc phylogeneLic sLrncLLire of Lrccs wiLhin six diameLcr classes (1--2,2--4, 4-7,7-11, 11 -- 16,>16 cm) in qnadraLs vviLh diffcrcnL size of 5 mx5 m, 10 mXlO m, 20 mx20 m, 50 mx50 m, 10() mx 100 m in a Abies georgei var. smithii comm uni Lv in a 4 hm2 s Lem-mapping ploL locaLcd in siibalpinc dark coniferous foresL of Sygera MounLains, soiiLhcasL TibeL. In various spa- Lial scales, hoLh neL relaLcdness index (JNH1) and ncarcsL Laxon index (JNT1) of Lhc commnniLy were larger Lhan zero, indicaLing a cliisLered phylogeneLic sLiucLnre vviLh Lhe largesL ckisLcring inLensiLv aL small spaLial scale (5 mX5 m). CommuniLv of small-sizc classes were phylogencLically clnsLcring. In large-size classes (JDB11>7 cm) phylogeneLic over dispersion bfcamc more common, vviLh dispersion increased vviLh increasing Lrcc size under all spaLial scales. ITie inLcnsiLy of phylogeneLic clnsLcring in young Lrecs increased vviLh increasing spaLial scales, while Lhe inLcnsiLy of over dispersion in large Lrecs (DB11>7 cm) increased vviLh spaLial scale. Our rcsiilLs siiggcsLed LhaL environmcnLal filLcring in small-size Lrccs and compcLiLivc exclusion in large-size Lrecs mighL be Lhc main ecological processes driving commnniLy assembly in Lhis region. [ABSTRACT FROM AUTHOR]

基于西藏色季拉山4hm2亚高山暗针叶林固定样地调查数据，分析了急尖长苞冷杉 群落内6个径级（1〜2、2〜4、4〜7、7〜〜16、〉16c.m）的植物在5个空间尺度（5 mx5 mJO mx 10 m、20 mx20 m、50 mx50 m、100 mx 100 m）上的谱系结构。结果表明：不同空间尺度上， 该群落的净谱系亲缘关系指数（NM）和净最近种间亲缘关系指数（W11）值均大于零，整体上 表现为谱系聚集。在小空间尺度（5 mx5 m）上，谱系结构聚集强度最大。在所有空间尺度 上，群落向小径级个体表现为谱系聚集，随着径级的增大c.m），逐渐表现为谱系发散， 且发散程度随径级增加而增大。小径级个体的谱系聚集强度随空间尺度而增大；而大径级个 体（DBW>7 cm）的谱系发散程度随空间尺度增加而增大。小径级群落的生境过滤和大径级群 落的竞争排斥作用可能是驱动该区域急尖长苞冷杉群落构建的主要生态学过程. [ABSTRACT FROM AUTHOR]

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