濒危植物大花黄牡丹（Paeonia ludlowii）种群数量动态

运用种群静态生命表、存活曲线、生殖力表和Leslie矩阵模型，研究了西藏特有的濒危植物大花黄牡丹种群数量动态过程。静态生命表和种群存活曲线反映出大花黄牡丹在树龄10a之前和20～25a之间分别经历了强烈的环境筛和竞争自疏，20a左右为其生理寿命，35a左右为极限寿命；大花黄牡丹种群的净增长率、内禀增长率和周限增长率较低，表现为衰退型种群；Leslie矩阵模型的模拟结果表明，在20a内种群幼苗数量和总数量呈现出下降趋势，下降了大约30%；大花黄牡丹种群存活表现为Deevey-Ⅰ型，早期个体死亡极高，幼龄苗木严重不足；现行种群数量主要是靠自身的萌蘖繁殖来维持。导致大花黄牡丹濒危的可能原因是大花黄牡丹的生物学特性以及人为干扰。

Numeric dynamics of the endangered plant population of Paeonia ludlowii

Numeric dynamics of population of Paeonia ludlowii, an endangered plant species mainly distributed in Nyingchi Prefecture of Tibet, were studied using the static life table, the survival curve, the fecundity schedule and the Leslie matrix model. Analytical results from the static life table and the survival curve reflect that Paeonia ludlowii underwent very strong environmental screening during its first 10 years and competitive self-thinning at the age between 20 to 25 years, the physiological life span of the species was about 20 years, and its maximum life span was about 35 years. The net reproductive rate, the intrinsic rate and the finite rate of increase of Paeonia ludlowii were relatively low, indicating that population of the species belongs to the type of decline. Results obtained by using the Leslie matrix model shows that both seedling numbers and total plant numbers of the species declined by about 30% during the past 20 years. The survival rate of Paeonia ludlowii population exhibits as the Deevey -I type, its mortality rate of individuals at the early stage was very high, and therefore it was short of young seedlings in its population. At present, the population is maintained mainly by shooting of itself. Thus, the possible factors leading to the species being in an endangering state are its biological characteristics and the disturbances from human activities.