陕西地区栓皮栎种群统计特征的区域变异性研究

种群统计是种群生态学研究的核心 ,主要研究种群在时间和空间上的数量变化规律。本文通过样方法对陕西不同地区栓皮栎的年龄结构、大小结构、密度结构和组成构件四个方面探讨栓皮栎种群的区域变异性规律。结果表明 ,从分布中心到分布边缘 ,沿生境梯度栓皮栎种群年龄结构呈现出不均匀分布 ,绝大部分样地幼苗和幼树的个体数量偏少 ,但栓皮栎种群能顺利通过瓶颈。不同样地不同年龄的栓皮栎种群的大小结构分布不一 ,种群中胸径小的个体与胸径大的个体数量比较少 ,中等大小的个体数量较多 ,种群表现出增长的趋势。不同样地的密度随径级的变化特点是低径级的密度高 ,高密度的径级小 ,密度在不同样地平均径级上的分布呈现出明显的负相关。不同样地的栓皮栎叶面积指数的变化 ,反映出栓皮栎种群的生长活力。

Study on Area Variability of Quercus Variabilis Population's Demonography Characteristics In Shaanxi Region

Population demonography is the core of the research on population ecology ,which mainly discusses the population amount regularity along with time and space. The population area variability law of Quercus variabilis from the age structure 、 size structure 、 density structure and architectural constitution in different regions in Shaanxi were probed and discussed via plots method. The results suggested that, the amount of individuals in 3 、4 years old classes is more than that of any other age classes in Louguantai plots, the amount of individuals in 2 、3 years old classes is the most in Machagou, the tree ages mostly are 5~10 years in Hanzhong region. The amount of seedlings and samplings differ between plots. That the amount of individuals in middle size classes exceeds that of larger size. Stump sprouting and seedlings are a common feature in plots of Louguantai. The amount of stump sprouting and seedlings accounts for 17% of total number in Machagou. The amount of stump sprouting almost accounts for 50% in Hanzhong region and the amount of large diameter classes and stump sprouting are more than the amount of seedlings in Huanglong region, but the population intend to increase .The mean density of Quercus variabilis is 1952 stands/hm 2 in Hanzhong region;1676 stands/hm 2 in Machagou;1597 stands/hm 2 in Louguantai;and 1500 stands/hm 2, and the lowest in Huanglong region. The dynamics of leaf area index reflects the vitality of Quercus variabilis population. In short, the age structure of Quercus variabilis population takes on uneven distribution along habitat gradient from core to margin, most of the plots have a few seedlings and samplings. However, Quercus variabilis population can pass through bottleneck. human beings disturbance 、predatory animals 、seed sprouting efficiency and so on influenced on Quercus variabilis population, it isn't limited by "bottleneck effect" because Quercus variabilis population inheres good resistivity and stump sprouting power, which will directly affect the Quercus variabilis population development.