四川卧龙自然保护区珙桐种群的空间分布格局

Spatial Distribution Pattern of Davidia involucrata Population in Wolong of Sichuan Province

采用扩散系数的t检验、Poisson分布的x2拟合检验及Morisita指数的F检验来研究珙桐种群的空间分布格局类型,用负二项参数(K)、Green指数(GI)和Lloyd的平均拥挤度(m*)与聚块性指标(PAI)来研究珙桐的聚集强度。同时利用上述指数研究取样尺度、海拔及克隆繁殖对珙桐种群分布格局和聚集强度的影响。结果表明,总体上珙桐种群的分布格局类型为集群分布,具一定的聚集强度。取样尺度、海拔对其分布格局和聚集强度均有不同程度的影响。基株种群和分株种群的分布格局和聚集强度在不同取样尺度和海拔下出现不同的变化。最后对珙桐种群格局在各种因素影响下的变化原因进行了讨论,认为珙桐种群格局呈集群分布的最主要原因是由其本身的繁殖特性决定的。

Davidia involucrata was a rare valuable and endangered plant in China. In this article, We studied the distribution pattern of its population with t test of Dispersal index, X^2 test of Poisson distribution and F test of Morisita＇ s index. Its assemble intensity is also analyzed through Negative binomial index, Green＇s index, Lloyd＇s index and Patchness index. In the mean time, we make use of those indexes to reveal the influences of block size, altitude and clonal reproduction on the distribution pattern and assemble intensity. The result indicates that the distribution pattern class of Davidia itwolucrata population is clmped pattern and it has strong assemble intensity in some degree. They are influenced by block size, altitude and clonal reproduction in different pitches. Moreover, Genet population and Ramet population vary with different altitude and block size. At last, we discussed the possible reasons that effect the changes of Davidia involucrate population＇ s distribution pattern and draw the conclusion that it mainly dues to its own character of reproduction.