极小种群海南风吹楠种群的数量特征及动态

Population quantitative characteristics and dynamics of Horsfieldia hainanensis,a rare and extremely small population plant

通过对广西分布区海南风吹楠野生资源的调查,从径级结构、静态生命表、存活曲线以及乔木重要值等方面,分析了海南风吹楠种群的生态学特征。结果表明:(1)海南风吹楠种群径级结构呈典型的倒J型,偏态分布极为明显,种群结构大致趋于稳定型,但径级结构、幼苗库存在明显不均衡性。(2)存活曲线趋于Deevey-Ⅱ型,幼苗阶段的高死亡率是导致其种群濒危的重要原因,且光因素是该树种生长和种群发展的限制性环境因子。(3)海南风吹楠在5龄级以前,树高与胸径的增长几乎呈线性相关,此后开始变缓。(4)海南风吹楠在群落中的竞争优势不明显,6龄级以后消失率增高。针对海南风吹楠濒危的原因,对现有种群进行适度人工干预,提高幼苗至幼树的转化率,加强片段化居群间的基因交流是当前海南风吹楠种群恢复的关键。

Through investigation into the wild resources of Horsfieldia hainanensis distributed in Guangxi, this article analyzes the ecological characteristics of the H. hainanensis population from aspects including diameter class structure, static life table, survival curve, the importance value of arbor tree, etc. The results are as follows：（1） the diameter class structure of the H. hainanensis population presents a typical inversed J-shaped distribution, which indicates that the population will still be a stable one in the short term, but the diameter class structure and seedling inventory show clear imbalance.（2）the survival curve tends to conform to the Deevey-Ⅱ type. High mortality during the seedling stage is an important factor that leads to the endangered status of the population, and besides, the light factor may also plays a role in limiting the growth and development of this tree species.（3）before reaching the 5th age class, the height and DBH of H. hainanensis almost show a linear correlation which tends to slow down thereafter.（4）the competitiveness of H. hainanensis in the community is not obvious, and the mortality rate among individuals after reaching the 6th age class increases. In view of H. hainanensis endangered reasons, Appropriate human intervention on the current population, raising the transformation ratio from seedlings to saplings and enhancing the gene exchange between fragmented population are the keys in restoring the current H. hainanensis population.