河南连康山自然保护区香果树种群结构与分布格局研究

    Population Structure and Spatial Distribution Pattern of Emmenopterys henryi in Liankang Mountain Natural Reserve, Henan Province

    • 摘要: 为研究河南南部大别山区香果树(Emmenopterys henryi)种群的结构及分布格局规律,采用典型样方法对河南连康山自然保护区香果树种群进行调查。结果表明:(1)连康山香果树种群的年龄结构呈现一定程度的偏正态分布,且不同样地之间种群结构存在一定差异。该种群表现出幼龄个体数量偏少、中龄个体集中、高龄级个体数量缺乏的共性特征,种群总体呈现衰退趋势;(2)存活曲线接近于DeeveyⅠ型,种群Ⅰ、Ⅱ级死亡率低,个体数量极少,但第Ⅶ和Ⅷ级死亡率大,存活曲线呈现下凹和断点,个体存活数(ax)和生命期望(ex)在Ⅱ级以上总体随径级增大而减少,ex随径级增加呈现一定的波动变化,种群稳定性不良。(3)利用负二项参数(K)、扩散系数(C)、扩散型指数(Iδ)、Cassie指标(Ca)、丛生指数(I)、平均拥挤指数(m*)和聚块性指标(m*/m)等参数对种群空间格局进行分析,结果表明香果树种群的空间分布格局呈集群分布,但不同样地种群的集群程度存在一定差异。(4)连康山香果树种群总体上处于被排斥的劣势地位,栖息地生境恶劣,外界不利因素多,在生态系统中占据生态空间的能力较小,建议开展异地繁育和迁地保存,促进濒危种群的有效保护和健康延续。

       

      Abstract: To study the population structure and distribution pattern of Emmenopterys henryi in Ta-pieh Mountain at the south of Henan Province, a typical sample method was used to investigate the E. henryi population in Liankang Mountain Natural Reserve. The results show that: (1) The age structure of the E. henryi population showed a certain degree of skewness distribution, and the population structures in different plots were different. The population presented the common characteristics of small number of young individuals, concentrated number of middle aged individuals and lacking of big individuals. (2) The survival curve was close to the DeeveyⅠtype, such as low mortality and very few individuals at age Ⅰ and Ⅱ, but the mortality rates at age Ⅶ and Ⅷ were high resulting in the concave and breakpoint of the survival curve. Both individual survival number (ax) and life expectancy (ex) decreased with the increasing of diameter-class after age Ⅱ, ex showed a certain fluctuation change with the increasing of diameter-class, suggesting a poor stability of the population. (3) The results of the analyses by using various coefficients and indices that the spatial pattern of the E. henryi population showed clumped distribution, while there were some differences in the clustering degree among different populations. (4) The E. henryi population in Liankang Mountain was generally in a disadvantageous habitat, and its ability to occupy ecological space in ecosystems was poor, so that, it is suggested to carry out seedling breeding and ex situ conservation to promote effective protection and healthy continuation of the endangered population.

       

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