长白山岳桦种群过渡带位置的研究

Position of Betula ermanii population ecotone in Changbai Mountains.

在长白山北坡 ,由于水、热条件及其组合的垂直分异 ,植被形成了完整的垂直带谱 .从表观上看 ,各植被带间存在明显的过渡带 ,但由于多种因素的影响 ,过渡带的位置确定比较困难 .文中采用梯度取样方法 ,应用分形分析、种群分布格局分析和种间竞争分析对海拔 14 0 0～ 2 2 0 0m的岳桦种群过渡带进行了定量研究 .结果表明 ,岳桦种群在海拔 16 5 0m附近与云冷杉林形成一个森林过渡带 ;在海拔 2 0

The vegetation on the northern slope of Changbai Mountains forms a vertical zone due to the vertical differentiation of moisture and heat conditions.Ecotones are obviously existed between different vegetation zones,but it is difficult to decide their positions.In the area from 1 400 m to 2 200 m elevation,we adopted the methods of gradient sampling,fractal analysis,population pattern analysis,and interspecific competition index analysis to describe Betula ermanii population ecotone.The results showed that there was a forest ecotone between Betula ermanii and Picea-Abies forest near elevation 1 650 m,and there was a forest line ecotone between Betula ermanii and alpine tundra near elevation 2 080 m.