红椿天然种群分布格局的检验方法

Testing Method for Distribution Pattern of Natural Toona ciliata Population

为研究濒危物种红椿（Toona ciliata Roem.）的种群分布格局,在谷城南河流域对发现的仅有两个红椿种群（T1、T2）以相邻格子法设置5 m×5 m、3 m×3 m的样方,精确到1 m格子。通过χ2验、Cx的t检验、Morisita I_δ的F检验,对种群分布格局进行判断是否符合泊松分布。结果表明,T1种群在5 m×5 m、3 m×3 m样方尺度下,C_x和I_δ均为泊松分布,5 m×5 m尺度χ2验为集群分布,3 m×3 m尺度为泊松分布;干扰种群T2种群密度较大,3种检验均为集群分布。因此,分布格局满足χ2验的泊松分布,样方设置应注重尺度和数量;df越大,理论值与观测值更可能越接近正态分布,种群分布格局的检验更加真实可信。

In order to research the population distribution pattern of endangered species Toona ciliata Roem.,the sampling plots of 5m×5m,3 m×3 m in size,accurated to 1 m×1 m,were established covering the two newly-found only existing T. ciliata Roem. communities（T1 and T2） with contiguous grid quadrate method,in the Nanhe River valley,Gueheng county. Chi-square test,distribution coefficient method Cx with t-test,Morisita pattern index Iδ with F-test were employed to check whether the distribution patterns of the T. ciliata Roem. populations conformed to Poisson distribution. The result indicated that,population T1 was in Poisson distribution with 5 m×5 m,3 m×3 m in size under Cx and Iδ methods,while in clumped distribution pattern with 5 m×5 m in size under the Chi-square test; however, the population was in Poisson distribution with the dimension of 3 m×3 m. Population T2 under human disturbance had higher population density,indicating clumped distribution under 3 above-mentioned tests. If Chi-square test satisfied,a distribution pattern is in Poisson distribution, dimension,quantity of sam- piing plots should be given priority to;df is greater,both theatrical value and observed value tend towards normal distribution more probably, and the test of distribution pattern, therefore will be more dependable.