甘肃省屈吴山自然保护区不同群落类型中白桦的大小级结构与种群动态

应用植物群落生态学的研究方法,对甘肃省屈吴山自然保护区不同群落类型中白桦种群胸径、株高的大小级结构以及动态进行了测定和分析,探讨了其动态过程及其机制。研究结果表明:在混交林群落中,白桦种群的大小级结构分布图的形状基本相似,并一致呈现为哑铃型,存活曲线为双峰曲线,为间歇型种群,幼苗、幼树贮备不足,具有衰退趋势;纯林中的白桦种群的大小结构为金字塔型,存活曲线为中间微凹而呈单折直线,种群具有稳定结构,能够长时间生存发展下去。探讨了导致种群结构缢缩的种群更新障碍及竞争效应。

Size structure and population dynamics of Betula platyphylla in different community types in Quwu Mountain Natural Resurve of Gansu province

The study on the size structure of diameter and height and dynamics of populations of white birch, Betula platyphylla, was carried out in Quwu Mountain Natural Resurve, situated in the north of Gansu province; with the methods of contiguous grid quadrats and spatial sere substituting for tine sere. On the basis of census of all individual抯 of white birch populations in different community types, the diameter structure and height structure of the white birch populations and their dynamics were described. The result showed that the diameter structure was correspond with the height structure, the size structure of white birch populations in mixed forest appeared irregular dumbbell type, the survival curve appeared double peaks, but it was still characterized by stable type, in comparison, the size structure of white birch populations in pure forest appeared pyramid model, and the survival curve was likely a linear with a little protruding. It was belonged to stable type suggesting that the population regenerates continuously.