Life histories of endangered Astragalus membranaceus population

Astragalus membranaceus is one of the endangered species in China.Analytical methods of the population structure, life table, survival functions are used to study life histories of A.membranaceus population in Xishui forest area of middle Qilian Mountains.The study showed that the population was declining gradually and individual plants of class I were not enough; the survival curve of the population appeared to be a type of Deevey Ⅱ; curves of survivorship, mortality rate, killing value reflected the whole population trends of dynamic changes; and functions of survival rate, cumulative mortality rate, mortality density and hazard reflected dynamic and structure of A.membranaceus population.Grazing and digging medicinal materials are main factors in imminent danger of the population.