飞播马尾松林林分空间结构对林下植被多样性的影响

以飞播马尾松中龄林为研究对象,通过典型样地调查,运用单因素方差及灰色关联分析方法,分析林分空间结构对林下植被多样性的影响。结果表明:(1)大小比数对灌木及草本层多样性及盖度影响均不显著(P0.05);角尺度、混交度对灌木及草本Shannon-Wiener指数影响显著(P0.05),且混交度对草本Patrick指数影响达到显著水平(P0.05);空间密度、开敞度对草本Shannon-Wiener指数影响显著(P0.05),且开敞度对灌木Patrick指数的影响达显著水平(P0.05),空间密度对灌木盖度的影响达显著水平(P0.05);各种空间结构指数对Pielou指数的影响均不显著(P0.05)。总体上,林下植被多样性表现为林木随机分布的林分高于聚集分布的林分,混交林高于纯林,中等密度林分高于高密度林分,开敞度基本充足的林分高于开敞度严重不足的林分。(2)受林下植被物种多样性影响最大的是空间密度,最小的是大小比数。因此,以调整林分密度为主,综合调整林木分布格局、树种结构及其开敞度,将有利于提高林下植被的多样性。

Effects of Stand Spatial Structure onU nderstory Vegetait on Di versity of Aerial Seeding Pinus massoniana Planta-tions

With the understory vegetation of aerial seeding Pinus massoniana plantations in the middle age , we explored the effect of spatial structure on the understory vegetation diversity by investigating the typical plots by one -way ANOVA meth-od and grey correlation analysis method .The results showed that: ( 1) Both uniform angle index and mingling degree had significant influence on Shannon-Wiener index of shrub and herb;the influence of mingling degree to Patrick index of herb also reached a significant level , while non-significant influence of neighborhood comparison was found on all diversity inde-xes of shrub and herb;both the effects of spatial density and opening degree on Shannon-Wiener indexes of herb were sig-nificant .The opening degree had a significant impact on the Patrick index of shrub and spatial density had a significant im -pact on the cover of shrub;non-significant relationship was found between all spatial structure indexes and Pielou index .O-verall, the diversity indexes of understory vegetation were the mixed stands>the pure stands , the stands of random distribu-tion>the stands of aggregated distribution , middle density stands>high density stand , and the stands of basically adequate opening degree>the stands of seriously short opening degree .( 2) Through the grey correlation analysis between the stand spatial structure indexes and understory vegetation diversity indexes , spatial density had the greatest influence on the spe-cies diversity of understory vegetation , and the minimum was the neighborhood comparison .Therefore, after giving priority to adjust the stand density integrated with regulating the spatial pattern of the tree , species structure and opening degree will be conducive to improve the diversity of the understory vegetation .