滇牡丹自然种群数量动态

Numeric dynamics of natural populations of Paeonia delavayi (Paeoniaceae)

运用种群静态生命表、存活曲线、生殖力表和Leslie矩阵模型研究了中国西南特有濒危植物滇牡丹(Paeonia delavayi)种群数量动态过程。静态生命表和种群存活曲线表明:滇牡丹在株龄3-6a之间经历了较强的环境筛,其单株生理寿命为15a左右,平均周期为8a,种群的净增殖率(R0=0.9857)、内禀增长率(rm=-0.0017)和周限增长率(λ=0.9983)表明其为衰退型种群;滇牡丹种群存活表现为台阶型曲线(B1型),分别在6a和12a阶段种群消亡率(Kx)较高。Leslie矩阵模型的模拟结果表明,在未来30a内种群数量呈现出下降趋势,大约下降了50%,其种群数量靠自身根系的萌蘖和种子繁殖共同维持。野生滇牡丹种群数量下降与其自身繁殖特性有关,但主要原因是人为采挖和生态环境的破坏。

Aims Paeonia delavayi （Paeoniaceae） is an endangered plant restricted to southwestern China. Our objective was to study the numerical population dynamics of the largest and most concentrated natural population in Shangri-La, Yunnan Province, China. Methods The distribution area of P. delavayi was investigated from 2009 to 2011. We studied the numerical dynamics of the population using static life table, survivorship and mortality curves, fecundity schedule and Leslie matrix model. Important findings P. delavayi underwent strong environmental screening at ages three to six years. The physiological life span was about 15 years, and generation span was eight years. The net reproductive rate （R0=0.985 7）, intrinsic rate of increase （rm=–0.001 7） and finite rate of increase （λ=0.998 3） were relatively low, indicating that the population was decreasing. The Leslie matrix model showed that plant numbers from seedlings and sprouts declined about 50% during the past 30 years. The survival rate exhibited a steep curve （B1 type）. The mortality rate of individuals was different at every stage, and the killing power （Kx） was high at the ages of six and 12 years. The present population is maintained mainly by sprouts and seedlings. Likely key threats to the species are the damaged ecological environment and human disturbances.