科尔沁沙地蒙古黄榆种群结构与空间分布格局

Population Structure and Spatial Pattern of Ulmus macrocarpa var. mongolica in Horqin Sandy Land,China

对科尔沁沙地分布的蒙古黄榆（Ulmus macrocarpa var.mongolica）疏林进行了调查研究,分析了其群落特征、种群结构和空间分布规律;编制了种群的静态生命表;绘制了年龄结构图、存活曲线和点格局分析图。结果表明：①蒙古黄榆疏林木本层的发育并不完善,种类单一,偶尔出现灌木层;②蒙古黄榆种群的年龄结构极不合理,呈明显的衰退型,并且幼树较少,更不存在0～10 a的幼树,天然更新严重不足,群落正处于严重的退化状态;③蒙古黄榆的种群静态生命表表明,死亡率最高出现在40～50年龄段,幼年个体的死亡率最低,它的存活曲线趋向于DeeveyⅠ型;④蒙古黄榆种群空间分布格局呈随机分布。

Based on an investigation into the Ulmus macrocarpa var.mongolica sparse forest in the Horqin Sandy Land,its population characteristics and spatial distribution were analyzed from aspects of static life table,mortality curve,age structure diagram and point pattern analysis diagram.The results showed：（1） The woody layer of the Ulmus macrocarpa sparse forest develops incompletely with single species,and the shrub layer appears sparsely,too.（2） The age structure of the Ulmus macrocarpa population is seriously defective with few saplings and even no saplings under 10 ages,and there is insufficient natural regeneration for the population.This community is in a serious degradation state.（3） The static life table indicates that the mortality of the Ulmus macrocarpa population is the highest during 40 to 50 years old and the lowest during the sapling stage.The survival curve of the Ulmus macrocarpa population tends to be the Deevey—I type.（4） The spatial pattern of the population obeys a random distribution.