【摘要】 海南苏铁是海南岛特有种和国家I级重点保护植物,对研究热带植物区系具有重要意义。受生境缺失及人为干扰等因素影响,海南苏铁在海南岛的种群数量呈缩减态势。采用种群年龄结构、静态生命表、存活曲线及种群动态量化分析等方法,对五指山地区不同生境下的海南苏铁种群进行了研究。结果表明:1)研究样地内的海南苏铁为稳定种群,低龄级和中龄级个体数占有一定的优势,但不同样地种群年龄结构存在一定的差异。2)静态生命表结果显示,3个样地整体上表现出随着龄级的增加高龄级个体数量减少的趋势,但样地A和样地B在幼龄级时有大量的个体数死亡。研究区内海南苏铁的存活曲线更趋近于Deevey-II型。3)种群动态量化分析结果表明,海南苏铁为低增长型的稳定种群,而样地A和样地B种群对外界干扰的敏感性要明显强于样地C。整体而言,五指山地区的海南苏铁种群当前仍处于一种稳定的状态。更多还原

【Abstract】 Cycas hainanensis C. J. Chen is one of endemic species in Hainan Island and first-class national protected wild plants in China, which has important implications for studies of tropical flora. C. hainanensis is suffering a population decline due to habitat loss and man-made disturbance. Based on the methods of population age class, stationary life table, survival curve and dynamic indices, the quantitative characteristics and dynamic trend of C. hainanensis population at different plots in Wuzhi Mountains were studied. The results show that 1) the population of C. hainanensis was stable according to the age class, which mean individuals of seedlings and mid-age trees were more than elder trees. However, there were some differences in age structure between different populations. 2) It was indicated by the stationary life table that the individuals of population were decreasing with age. At the same time, many seedlings were loss in plot A and plot B. The survival curve of C. hainanensis population mainly belonged to Deevey-II type in study area. 3) In light of the results of dynamic indices, it also implied that the characteristic of C. hainanensis was a stable population. Whereas, the population of plot A and plot B were more sensitive to environmental disturbance than plot C. It is concluded that the population of C. hainanensis distributed in Wuzhi Mountains is still stable and current levels of recruitment are enough to maintain this population of long-lived trees.更多还原