乌冈栎种群数量动态分析

Analysis of the Population Dynamics of Quercus phillyraeoides

采用典型抽样和样方调查的方法,分别对将石、开化、仁化、沅陵和荔波的乌冈栎野生种群进行了调查。基于"空间代替时间"的方法,以种群径级结构代替年龄结构,采用静态生命表、生存分析和空间分布格局理论,对各地乌冈栎种群的结构与动态进行了分析。结果表明:①不同地区乌冈栎种群的径级结构分布呈现出较大的差异,除湖南沅陵种群为增长型外,将石、开化、仁化和荔波的种群呈纺锤形或倒金字塔形,有径级缺失的现象;②乌冈栎种群的高度级与胸径级成呈显著正相关性,其拟合为幂函数方程y=2.024 6x0.439 9(R2=0.741 4,P<0.001);③各地乌冈栎种群标准生命表的数据均有负值出现,这说明种群整体或局部径级有衰退的迹象,中等径级个体对维持乌冈栎种群具有重要意义;④存活率曲线、死亡曲线和致死率曲线均呈现出波浪式的变化,表明种群自然更新过程存在明显的周期,这可能也是长期维持乌冈栎种群在群落中优势地位的重要动力之一;⑤种群数量动态变化Vpi指数显示,除广东仁化种群表现为典型的衰退种群外,其余地区的Vpi指数值均大于0,但其偏离0的程度均较小,不属于典型的增长种群;⑥乌冈栎种群的方差/均值比率(s2/x-)的结果均大于1,说明各地区乌冈栎种群的分布呈聚集分布,平均拥挤度(m*)、Green指数(GI)、聚集度指数(CI)、负二项式参数(k)等变化趋势基本一致。

Using the method of typical sampling and surveys,the populations of Quercus phillyraeoides were investigated in different districts,including Jiangshi,Kaihua,Renhua,Yuanling and Libo.Based on the methods of spatial series substituting for time series and size structure replacing age structure,the study was made on the population dynamics and structure of Quercus phillyraeoides in terms of time specific life table,survival analysis and spatial pattern.The results showed： ① the size class structure ratio of Quercus phillyraeoides was different among the 5 populations,which showed spindle-shape or inverted pyramid form of Jiangshi,Kaihua and Renhua;the population of Hunan Yuanling was the growth form,but the size class structure of Guizhou libo＇s was not integrated.② there was a significant positive correlation between height and DBH of Quercus phillyraeoides,and the fitted curve was the power equation y=2.024 6x0.4399（R2=0.741 4,P0.001）.③ the negative number existed in the time specific life table in different populations,which indicated that the certain populations had the signs of recession,and the mid-size class individuals were very important for the population to maintain the dominant position in the communities.④ the change of survival curve,death curve and killing curve were wave mode,which revealed that a marked regularity of periodic fluctuation was in the process of natural regeneration,and maybe it was the main power for Quercus phillyraeoides to keep the dominant population.⑤ the Vpi index showed that Guangdong Renhua＇s was typical diminishing population（Vpi0）,and the populations in the other places were increasing ones,but their values of Vpi were not significantly deviating from 0.⑥ the values of s2/ was more than 1,which meant that the spatial pattern of Quercus phillyraeoides population belonged to the aggregated distribution,and the index of m＊,GI,CI and k had the same variation trend.