湖北赛武当国家级自然保护区金钱槭(Dipteronia sinensis)种群的数量动态

金钱槭(Dipteronia sinensis)是我国特有的珍稀植物。为探究其种群的数量动态变化规律, 以湖北赛武当自然保护区金钱槭种群为研究对象, 通过样地调查, 编制了金钱槭种群的静态生命表并绘制其存活曲线、死亡率曲线、消失率曲线以及4个生存函数曲线, 同时结合种群年龄结构的数量变化动态和时间序列分析方法来探讨金钱槭种群的数量动态。研究表明: 1)金钱槭种群年龄结构存在一定的波动性, 其幼龄阶段的个体较多, 中龄次之, 成龄的个体数量最少; 种群的生存曲线更接近于DeeveyⅢ型。2)金钱槭种群的生存率呈现单调下降的趋势, 而累积死亡率呈现单调上升的趋势。3)金钱槭种群的死亡密度曲线和危险率曲线的走向相一致, 但是危险率的值都比死亡密度的值略大一些。4)时间序列分析显示金钱槭种群在3、6、9年后的数量预测中整体上呈现出小幅度增长的趋势, 并且种群动态指数>0, 表明金钱槭种群为增长型种群。研究结果为进一步保护金钱槭提供依据。

Quantitative dynamics of Dipteronia sinensis populations in Saiwudang Nature Reserve,Hubei province

Dipteronia sinensis is an endemic and III grade rare and endangered plant species in China.To characterize the numerical population dynamics of D.sinensis,we performed sample-plot survey in Saiwudang Natural Preserve in Hubei Province and analyzed the dynamics of age structure,the time sequence analysis and the static life tables,which explicated the curves of survival rate,mortality rate,vanishing rate as well as four survival function curves.The results showed that:1)The age structure of population exhibited certain fluctuation with most trees in the early growth stage rather than in late growth stage and therefore resulted in type DeeveyⅢof the survival curve.2)The survival rate of the population decreased monotonically,whereas the cumulative mortality rate was rising.3)The mortality density and hazard rate showed the same trend but the hazard rate was always a little higher than the mortality density.4)The time sequence analysis showed a slight rising tendency of the population quantity in the coming 3,6 and 9 years and zero-above level of the dynamic indices Vpi,indicating a growth type population of D.sinensis.