中文摘要：

裸果木（Gymnocarpos przewalskii）为古地中海旱生植物区系孑遗种,是砾质荒漠的主要建群种之一。通过对安西极旱荒漠国家级自然保护区内3种生境（水冲滩地、山间冲沟、平缓戈壁）条件下裸果木种群的样地调查,编制不同生境裸果木种群的静态生命表,绘制其存活曲线和生存分析函数的曲线,并采用时间序列模型对种群的数量动态进行预测,以揭示不同生境下裸果木的种群结构和动态特征。结果表明：3种生境下裸果木种群均属增长型,数量变化动态指数（V’pi）〉0,但对外界干扰比较敏感,存活曲线趋于Deevey-II型,表明种群各龄级的死亡率基本接近;不同生境裸果木种群大小依次为水冲滩地〉山间冲沟〉平缓戈壁,结合对种群年龄结构的分析,进一步表明水分条件较好的水冲滩地和山间冲沟生境更加适宜裸果木生存;生存分析和时间序列预测表明幼龄个体的缺乏是未来裸果木种群发生衰退的主要原因,且平缓戈壁生境下的裸果木种群将先于另外两种生境下的种群发生更加快速的衰退。

英文摘要：

Aims Gymnocarpos przewalskii is a relict plant of the Tethys flora, which is also one of the constructive species in stony desert. Our objective was to determine the structure and dynamic characteristics of G. przewalskii in different habitats. Methods Based on the equal-area plot investigations in three habitats of G. przewalskii, the static life table was established, survival curves and the function curves derived from the survival analysis were also constructed to evaluate the population characteristics. The population dynamics were predicted by a time-sequence model. Important findings The survival curves of G. przewalskii appear to approach the Deevey-II type, which indicate that the mortality rate in different size classes was similar, and the population fit in with the growing type in all habitats, but sensitive to environment disturbances. The population size of G. przewalskii was largest in flooding lands, medium in gullies and smallest in the flat desert and the age structure showed that the flooding lands and gullies are better habitats for the growth of G. przewalskii. The survival analysis and the time-sequence model demonstrated that the lack of young individuals could be the major cause for population declines of G. przewalskii in all habitats; moreover, a decline is likely to occur in the flat desert earlier and quicker.