白桦种群的稳定性与火干扰关系的研究

STUDY ON THE RELATION BETWEEN THE STABILITY OF BETULA PLATYPHYLLA POPULATION AND THE FIRE DISTURBANCE

从种群生态学和干扰生态学的角度出发，在火史重建的基础上，采用种群世代划分的方法，研究了大兴安岭北部白桦种群的稳定性与火干扰的关系。结果表明：白桦种群的耐火力与自我恢复力都较差，主要依靠很强的火后恢复力维持其稳定性。种群耐火力与长期火状况密切相关，表现为：低频类＜中频类＜高频类，高强类＜中强类＜低强类。火后恢复力与自我恢复力和最近一次火烧强度及距今时间密切相关：火后恢复力与自我恢复力都以低强类＞高强类＞中强类：火后恢复力以短期类＜长期类＜中期类；自我恢复力以短期类＜中期类＜长期类。研究指出：火干扰频繁而低强的大兴安岭北部地区正是白桦种群最适宜的火环境；火后更新是种群维持稳定的主要方式，林冠下更新是其重要的辅助方式。

This paper, which is from the view of Disturbance and Population Ecology and based on the reconstructing fire disturbance history from live and dead materials, studies the relation between the stability of Betula platyphylla population and the fire disturbance in the northern Daxinganling Mountains with the method of division of population cohort. The result reveals that: Betula platyphylla population is stable depending on its strong post-fire resilence, but the fire resistance and self-resilience are weak. The fire resistance of population is related to the fire disturbance regime, the ranks of different fire regime type are listed follows: low frequency<middle frequency<high frequency, high severity<middle severity<low severity. The post-fire resilience and self-resilience are related to the last fire regime, and the post-fire resilience shows follow sequences: short period<long period<middle period. The self-resilience is that: short period<middle period<long period. Both the sequences of the two resilences are that: low severity>high severity>middle severity. This research concludes that: Betula platyphylla population is adapted to the fire disturbance regime of low severity and high frequency in the northern Daxinganling Mountains. The post-fire regeneration is the major manner for Betula platyphylla population keeps stable and the regeneration under the canopy is an assistant one.