海南吊罗山热带雨林桫椤种群结构与动态特征

Population Structure and Dynamic Characteristics of Alsophila spinulosa in Diaoluo Mountain Tropic Rain Forest of Hainan

根据样线调查和数据统计,以桫椤(Alsophila spinulosa)个体及主茎高度分级为基础,通过静态生命表、存活曲线、时间序列预测等方法,研究了海南吊罗山热带雨林桫椤种群结构与动态特征,剖析了桫椤种群生存现状及未来发展趋势。结果表明:研究区桫椤种群年龄结构整体表现为金字塔型,但由于环境差异使不同样线的种群结构有一定的差异。静态生命表显示桫椤种群在I龄级具有较高的死亡率和消失率。上游和中游种群的存活曲线为DeeveyⅢ型,而下游为DeeveyⅡ型。种群动态量化指数亦表明研究区的桫椤为增长种群,但对外界干扰具有较高的敏感性。时间序列预测显示,随着时间的推移,各龄级在未来的种群数量多数呈增长状态。吊罗山热带雨林的桫椤种群具备天然更新的能力,保持现有群落结构和生境有利于当前桫椤种群繁衍。

Based on line transect survey and data statistics, the population structure and dynamic characteristics of Alsophila spinulosa population in the tropical rainforest of Daoluo mountainshan of Hainan province are studied by static life tables, survival curves and time series prediction on the basis of individual and main stem grading. The current situation and future development trend of the population are analyzed. Results indicate that the age structure of Alsophila spinulosa populations in the study area is pyramidal, but there are various in the each line transect due to environmental differences. The static life table show that Alsophila spinulosa population has a high mortality and disappearance rate in the age class Ⅰ. The survival curves of the upstream and midstream populations are Deevey Ⅲ, while the downstream is Deevey Ⅱ. The quantitative index of population dynamics indices also indicated that Alsophila spinulosa in the study area is a growing population, but it is highly sensitive to external disturbances. Time series predictions show that the population size of each age class increased in future. The population of Alsophila spinulosa in the study area have the ability for natural regeneration, and maintaining the current community structure and habitat is conducive to the reproduction of the populations.