洪水干扰对青冈种群更新的影响

INFLUENCE OF FLOOD DISTURBANCE ON THE REGENERATION OF CYCLOBALANOPSIS GLAUCA POPULATIONS

本文在安徽黄山选择位于溪谷、受洪水干扰程度不同的3个样地，调查青冈种群的更新特征，结论如下：①从幼苗数量来看，受洪水影响最轻的样地3最多，密度为0.5825株m-2，洪水影响最严重的样地1数量最少，密度仅为0．1150株m-2；从幼苗性质来看，样地1萌生苗比率最高．3个样地中，随着高度级别增加，萌生苗的比例也增加。②萌生苗高度的分布接近于对称的低峰分布，实生苗的偏斜度均为正值。所有的Gini系数都较大，平均为0．5260，说明大小不等性较大。③3个样地中萌生苗均为集聚分布，样地2、3中实生苗为随机分布，而样地1由于洪水干扰较严重，实生苗多集中于地势较高的一端，呈集聚分布。以上结果表明，青冈种群的更新受洪水影响较大，溪谷种群形成了以无性繁殖为主的更新对策。

Three plots of CyclobalanoPsis glauca populations suffered to different extent from flood disturbance in valleys of Huangshan Mountain, Anhui Province, were chozen to study the seedling characteristics of the populations. The results showed that one of the plots, i.e.plot 3, which was least disturbed by the flood had more seedlings than the others, the population density of the seedlings being 0.5825 individual m-2. The density in plot 1 being heavily suffered from the flood was 0.1 150 individual m2 only, but the proportion of seedling sprouts was the highest in this plot. In all the three plots, the percentage of seedling sprouts increased with the seedling height. The distribution of seedling sprout height was nearly symmetric and platykurtic, but was positively skewed for the seedling plants. All the Gini coefficients were high (0.503l -0.5623), indicating that the size inequality was large.The seedling sprouts in all plots were in clumped distribution, while the seedling plants in plot 2 and 3 were in random distribution. However, clumped distribution was found in plot 1 for seedling plants distributed at higher edge due to the flood disturbance. It is concluded that C. glauca populations at sites disturbed by flood regenerated mainly by vegetative propagation instead of sexual propagation.