濒危植物水青树的种群结构与数量动态

以种群生命表及生存分析理论为基础，将林木依胸径大小分级，以林木径级结构代表年龄结构，采用分段匀滑技术，编制四川草坡自然保护区水青树Tetracentron sinense种群特定时间生命表，绘制存活曲线、死亡率曲线、消失率曲线、生存函数曲线，分析种群数量特征；同时结合时间序列模型，分析该种群数量的动态变化。结果表明：(1)草坡自然保护区的水青树的年龄结构表现为稳定型，虽然幼苗较多，但幼树死亡率高，种群处于衰退早期；(2)水青树种群死亡率和消失率曲线变化趋势基本一致，均在第Ⅲ龄级出现一高峰，即幼树死亡率较高；存活曲线趋于Deevey-Ⅱ型；(3) 4个生存函数曲线表明，水青树种群具有前期锐减、中后期相对稳定和末期衰退的特点，其种群处于衰退早期；(4)种群的时间序列预测模型分析表明，在未来9年水青树种群数量将下降，老龄个体逐渐增多，幼龄株数更显不足，呈衰退势态。

Population Structure and Dynamics of Endangered Plant Tetracentron sinense

Based on population life table and theory of survival analysis, the individuals of Tetracentron sinense in Caopo Nature Reserve of Sichuan Province were graded according to the size of diameter at breast height, and the age structure was represented by tree diameter structure. The static life table of T. sinense population was compiled by smoothing out technique. The mortality rate curve, killing power curve, survival rate curve, and survival function curve were also analyzed to reveal the quantitative characteristics of T. sinense population. Additionally, quantitative dynamics of the population was predicted using Time Series Model. The results showed that: (1) The age structure of T. sinense in Caopo NR was stable and the seedlings were abundant, but the mortality of sapling was relative higher, indicating the recessive characteristic of the population. (2) The mortality rate curve and killing power curve of T. sinense population in lifespan had similar variation trend, which had a peak in third age-class, i.e. the sapling mortality rate was higher and the survival curve of population tended to Deevey-Ⅱ. (3) The four survival function curves showed that T. sinense population decreased quickly in early age period, and became stably in middle age period, but declined in old age period. (4) Time Series Forecasting Model showed that population quantity of T. sinense decreased in the next 9 age-classes, the number of aged individuals gradually increased, the young plants was decreasing, indicating the recessive character of the population.