大相岭龙苍沟珙桐种群空间分布格局研究

Spatial Distribution Pattern of Davidia Involucreta Population in Longcanggou in Daxiangling Nature Reserve

在大相岭龙苍沟高桥河、清水河、黄沙河流域设置三块珙桐样地,以样地调查数据为基础,运用离散分布的理论拟合,聚集强度指数的测定,对珙桐种群的空间分布格局进行研究分析,研究结果表明珙桐种群的空间分布格局特征为:在幼苗到幼树阶段为聚集分布,逐渐过渡到大树阶段的随机分布。在幼苗到幼树阶段具有较强的聚集度,主要是因为珙桐种子散布比较困难和主要靠萌蘖更新。随着幼苗向大树发育的全过程,环境因子作用加强,种内、种间竞争加剧,幼苗、幼树呈现出较高的死亡率,林木自然稀疏,导致分布格局逐渐过渡到随机分布。

Davidia involucrata is a rare valuable and endangered plant in China. In this article, we studied the distribution pattern of its population based on the data of sample field investigation and the theory of discrete distribution and the assemble intensity. The result indicates that the distribution pattern of Davidia involucrata population is clumped pattern and it has strong assemble intensity in seedling and young tree phrases because of difficult spread of seed and regeneration by tillering. The distribution pattern changes from clumping to random gradually from the young tree to old tree because of the competition and high death rate of young tree.