珍稀濒危植物桫椤种群结构与动态特征

Population structure and dynamics of Alsophila spinulosa,a rare and endangered plant

珍惜濒危孑遗植物桫椤对研究古生物发展、古气候环境变迁具有重要价值。研究采用样地调查法对样地内所有桫椤植物进行地理定位与调查,对赤水桫椤种群进行年龄结构量化分析、生命表分析、生存分析。结果表明:赤水桫椤种群属于增长型种群;赤水桫椤种群低龄级、中龄级、成龄级、老龄级数量分别占比39.8%、46.8%、12.5%、1.0%;具两次死亡高峰,存活曲线为Deevey-Ⅱ型。赤水桫椤种群抗干扰能力差,种群更新不及时会导致种群结构走向衰退,应加强对低龄、成龄个体的保护与龄级更替机制的探索。年龄级新判定方法的提出、简化群落结构与原生境植株栽培或许是提高赤水桫椤种群天然更新能力的有效途径。

The rare and endangered plant Alsophila spinulosa is of great value for the study on paleontological development and paleoclimatic environment changes.In this study,all the Alsophila spinulosa plants in the sample plot were located and investigated,and the age structure,life table and survival of the Alsophila spinulosa population in Chishui were quantitatively analyzed.The results showed that the Alsophila spinulosa population in Chishui belonged to the growth type.The proportion of low-age,middle-age,adult,and old-age classes in the population were 39.8%,46.8%,12.5%,and 1.0%,respectively.There were two death peaks and the survival curve was Deevey-Ⅱtype.The weak anti-disturbance ability of the population would lead to the decline of the population structure.Therefore,it is necessary to strengthen the protection of the young and adult individuals and to explore the mechanism of age level replacement.The proposal of new age classification method,the simplification of the community structure and the cultivation of native plants may be an effective way to improve the natural regeneration ability of the Alsophila spinulosa population in Chishui.