红椿天然种群分布格局尺度研究

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检验、Cx的t检验、Morisita Iδ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,Cx和Iδ均为泊松分布,5 m×5 m尺度 χ2检验为集群分布,3 m×3 m尺度为Poisosn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检验的泊松分布,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.

Distribution Pattern Scale of Natural Toona ciliata Population

In order to research the population distribution pattern of endangered species Toona ciliata Roem., the sampling quadrats of 5 m×5 m and 3 m×3 m in size, accurate to 1 m×1 m, were established in 2 newly-found only existing T. ciliata Roem. communities (T1 and T2) with contiguous grid quadrate method, in the Nanhe River valley, Gucheng County. By χ2 test, t -test of distribution coefficient Cx method, and F test of Morisita pattern index Iδ, whether the distribution patterns of the T. ciliata Roem. populations conformed to Poisson distribution were checked.The results indicated that, population T1 was in Poisson distribution under 5 m×5 m and 3 m×3 m in size by Cx and Iδ methods, but in clumped distribution pattern under 5 m×5 m in size by the Chi-square test; however, the population was in Poisson distribution under 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 is satisfied, a distribution pattern is in Poisson distribution, and size and quantity of sampling quadrats should be given priority to; and if df is greater, both theoretical values and observed values tend towards normal distribution more probably, and the test of distribution pattern, therefore will be more dependable.