巴山木竹无性系种群的分布格局

The Spatial Pattern of Arundinaria fargesii Clone Population

在巴山木竹(Arundinaria fargesii E.G.Camus)混交林中采用邻接格子样方法、样线株间距法取样,研究了巴山木竹无性系种群分布格局,并用克隆生长系数的变化揭示了无性系种群的克隆生长型动态。结果表明,巴山木竹无性系种群的分布格局在各年龄范围均是集群分布,格局规模即斑块大小均为92.16 m2,格局强度(RDD)达到3.89;说明巴山木竹无性系种群聚块(密距段)分株数是间隙(疏距段)分株数的3.89 倍。格局纹理为38.17 cm,即从一个聚块(密距段)到另一个聚块(密距段)的聚块平均间距是38.17 cm。巴山木竹无性系种群的克隆生长型中以合轴型分株占主导地位。从巴山木竹种群各年龄范围均保持强集群分布格局并有随时间进程逐渐加强的趋势来看,该种群可能受到了较大的环境压力。

The study on the bamboo population could provide a theoretic and scientific basis for prediction of bamboo population succession,fostering of bamboo forest and protection of bamboo germplasm.The spatial pattern of Arundinaria fargesii clone population and the clone growth form of ramets(percentage of ramets with single axis within a clone) were studied by using the method of contiguous grid quadrats,distance among the ramets along the sample line to sampling,t-test for variance/mean and χ~2-test for Poisson-distribution to test the spatial patten,drawing the pattern analysis graph to confirm the pattern scale,and using mean crowd index(m),clumping index(C) and relative density difference(RDD) to calculate the pattern intensity,using mean clearance distance to show the pattern grain and using the change of clone growth index to show the dynamics of clonal growth.The results showed that the spatial pattern of A.fargesii clone population was the clumped distribution and the pattern scale was at 92.16m^2,the relative intensity difference(RDD) was 3.89,the pattern grain was 38.17cm.The sympodial ramets hold the dominant status in the clone growth of the A.fargesii clonal population.The strengthening trend of the clumped distribution with ageing implies that the population was under a relatively stronger environmental pressure.