山西七里峪白桦种群生活史特征与点格局分析

Life history characteristics and point pattern of Betula platyphylla population in Qiliyu region,Shanxi,China

为了解山西七里峪地区白桦种群的生活史动态特征与空间分布规律,本文对七里峪高海拔地区白桦种群的生命表特征、年龄结构、存活曲线以及种群空间分布格局4个方面进行了研究。结果表明:七里峪地区白桦种群径级结构呈纺锤形,属衰退型种群;白桦种群的存活曲线基本接近DeeveyⅠ型,即曲线凸型;种群由于争夺光照和生存空间,第Ⅲ龄级的死亡率较高,自疏作用比较明显;在研究尺度内白桦种群不同年龄级的个体呈现出集群分布或随机分布,在种间竞争较小的情况下,白桦种群呈集聚分布,且随着龄级的增加,集群分布趋势明显,白桦种群自身的生物、生态学特性是影响其分布格局的最主要因素。

In order to understand the life history characteristics and the pattern of the spatial distribution of Betula platyphylla population in the Qiliyu region of Shanxi Province, the life table characteristics, age structure, survival curve and spatial distribution of the B. platyphylla population were studied. The results showed that, 1 ） the age structure of the B. platyphylla population of the Qiliyu region followed a spindle shape, which indicated that the population was declining; 2） the survivorship curve of B. platyphylla population approximated the type of the Deevey I ; 3 ） self-thinning was common in this population, because of the high inter-specific competition for space and sunlight, which led to a higher death rate in age class III; 4） the spatial distribu- tion in different growth periods was clumped or random. To he specific, the distribution pattern tended to be clumped when inter-specific competition was not intense, and the clumping distribution became more significant with age increase. Based on our findings, we concluded the spatial patterns of the B. platyphylla population in this area of uniform environment conditions were controlled by biotic interactions and local ecological characteristics.