甘肃小陇山红桦林种群结构和分布格局

Analysis on Red Birch Population Structure and Distribution Pattern in Xiaolongshan of Gansu

为了揭示小陇山红桦种群的维持机制,结合径级结构、静态生命表和存活曲线,对小陇山红桦种群结构进行了研究;并应用多个聚集强度指标(方差/均值比率法、负二项参数、Cassie指标、丛生指标)和聚块性指数,对甘肃小陇山红桦林种群的分布格局及其动态进行了测算分析。结果表明:目前红桦林种群为衰退群落;其分布格局呈现一般聚集分布,但聚集强度变化不大;随着群落中红桦林种群的发育进程,分布格局的时间模式为从均匀分布到集群分布,最终趋于随机分布。

In order to reveal population maintenance mechanism of red birch in Xiaolongshan of Gansu,combined with diameter class structure,and static life table survival curve,the population structure of red birch were studied in Xiaolongshan.The application of multiple aggregation intensity index（variance/mean ratio method,negative binomial parameters,Cassie index,clumping index）and the cluster index was used to work out distribution pattern and dynamics of red birch population.The results showed that the red birch forest populations to decline communities;its distribution pattern was generally aggregated distribution,but its gathered strength changed little.Along with the community of red birch population development,distribution pattern of the time pattern ranged from a uniform distribution to the cluster distribution,and tended to be randomly distributed.