西藏色季拉山长鞭红景天种群动态及其保护

Quantitative Dynamics and Protection Methods of Rhodiola fastigiata,An Endangered Tibetan Medicinal Plant

长鞭红景天是国家二级保护植物,目前处于近危状态。基于样地-样方调查资料,对长鞭红景天种群年龄结构进行动态量化分析,编制种群静态生命表,绘制种群死亡率曲线、消失率曲线、存活曲线以及生存函数曲线,并运用时间序列模型分析种群数量动态。结果表明,长鞭红景天种群年龄结构总体上呈金字塔型,种群数量变化动态指数Vpi和Vpi均大于零,表明种群属稳定增长型。长鞭红景天种群各龄级个体数量随龄级增长呈逐渐下降趋势,Ⅱ龄级至Ⅴ龄级死亡率较高、达90.29%,整个过程平均死亡率为29.96%,种群存活曲线属Deevey-Ⅱ型B3亚型,种群死亡率与消失率随龄级增长的变化趋势基本保持一致,呈"M"型曲线。生存函数分析表明,长鞭红景天种群前期(Ⅳ龄级前)快速下降,中期(Ⅳ—Ⅵ龄级)相对平稳,后期(Ⅵ龄级后)进入生理衰退期。时间序列预测发现,长鞭红景天种群幼龄个体数量较丰富,未来Ⅱ,Ⅴ和Ⅷ个龄级时间后种群各龄级个体数均有不同幅度的增长。建议保护和改善长鞭红景天种群生存的原生境条件,适当人工辅助散播,建立培育基地及基因库、实施迁地保护,加强病虫害监测。

Rhodiola fastigiata is an endangered Tibetan medicinal plant,which is regarded as a plant of the second-class protection in our country.Based on investigation data of plots and quadrats,the paper an-alyzed the age structure of R.fastigiata population,compiled the static life table,drew mortality curve, killing power curve,survival curve,and survival function curve.The population quantitative dynamics was predicted by the time sequence prediction model.Results showed that the age structure of R.fastigiata population was presented as the typical pyramid shape.The two dynamic indexes of Vpi and Vpi of the popu-lation quantity were 33.89% and 1.69 %(both more than zero),respectively,which showed the popula-tion was steadily increasing.The survival number of every age class was decreasing with the increasing age class.The mortality rate of age class Ⅱand Ⅴ were relatively high(reached 90.29%),and the average mortality rate accounted for 29.96%.The survival curve of R.fastigiata population approached the B3 subtype of Deevey-Ⅱ.With the changing age class,the mortality rate had a similar change trend to the killing power,and they were both M shape curves.The survival functional curve for R.fastigiata popula-tion indicated that the population was characterized by reduction in the early age period(before age classⅣ),stableness in middle age period(Ⅳ-Ⅵ age class),and recession in late age period(after age classⅥ)because of physiological exhaustion.The young individuals would be relatively abundant,and the pop-ulation would show a trend of steady growth in the upcoming Ⅱ,Ⅴ and Ⅷ age classes.We suggested some things to be done were as follows to protect R.fastigiata,protecting and improving primitive habitat conditions,developing proper artificial seeding,building reproduction base and gene bank,implementing ex-situ conservation,strengthening monitoring of diseases and insect pests.