4种地被竹大个体空间分布的点格局分析

Point pattern analysis on the distributions of large individuals of four dwarf bamboos

【目的】植物个体大小存在的差异,是植物种群空间结构的重要影响因素,笔者探究大个体在种群空间中分布的类型、大小个体间的相互作用,为城市绿化提供基础数据。【方法】选取南京林业大学校园内翠竹(Pleioblastus pygmaeus)、髯毛箬竹(Indocalamus barbatus)、菲白竹(P.fortunei)和铺地竹(Pleioblastus argenteostriatus)4种地被竹种,依据竹株高度分为大个体组(观测组)和小个体组(控制组),运用空间聚集性的二阶分析法,并结合Monte-Carlo检验,分析大个体的空间分布类型,使用估计的方法计算空间强度趋势面。【结果】翠竹、髯毛箬竹、铺地竹的大个体竹株分别在其给定的距离尺度下呈现出显著的随机分布,未表现出聚集性特征;菲白竹大个体则在给定的距离尺度下呈现出较弱的随机分布;4种地被竹在各自样地内的分布存在不同特征上的理论强度。【结论】地被竹个体大小的差异影响个体在生长空间、资源等方面的竞争,大个体的空间分布是地被竹种群在生境中综合能力的外在表现。自然环境中,地被竹种群在个体差异基础上,通过自身调节机制和一系列生态过程,形成特定的空间结构。

【Objective】There exists a large difference in body size among individuals of the same plant species,which is an important factor for affecting the spatial structure of plant populations. In this study,we aimed to explore the types of spatial distributions of large individuals in population,examining the interaction between large and small individuals,and to provide basic information for city verdurization.【Method】Four species of dwarf bamboos were chosen from the campus of Nanjing Forestry University,namely Pleioblastus pygmaeus,Indocalamus barbatus,P. fortunei and P. argenteostriataus. We divided dwarf bamboo into two groups： large individuals（ cases） and small individuals（ controls）,then used the second-order analysis of spatial clustering combined with the Monte-Carlo test,to analyze the spatial distribution types and calculated the intensity surfaces.【Result】The results showed that：（1） The P. pygmaeus,I. barbatus and P. argenteostriataus exhibited random Poisson distribution on given distance scales and no clustering characteristics.（2） The P.fortunei also exhibited a random distribution,but it is slightly weaker than the other three species;（3） The four studied dwarf bamboo species had different intensity surfaces in their corresponding study regions.【Conclusion】Difference in the body size among the dwarf bamboos can affect the dynamics of intraspecific resource（ especially in space） competition.It also indicated that spatial distribution pattern of large individuals reflects the external performance of the comprehensive capacity of dwarf bamboo populations in habitats. In the natural environment,based on the individual difference in size,dwarf bamboos populations forms special spatial structures through its own regulation mechanism and aseries of ecological processes.