准噶尔盆地西北缘梭梭种群结构和空间格局特征

Population Structure and Spatial Pattern of Haloxylon ammodendron Population along Northwestern Edge of Junggar Basin

为了揭示准噶尔盆地西北缘梭梭种群的分布特点,结合径级结构、静态生命表和存活曲线,对准噶尔盆地西北缘两种典型生境条件下梭梭种群年龄结构和空间分布格局进行了研究。研究显示,在不同生境条件下,梭梭种群径级结构差异明显。山前戈壁梭梭种群Ⅰ、Ⅱ、Ⅲ径级个体数占所有径级个体总数的96.21%,大径级个体缺失,该种群发育时间较短,种群处于增长阶段;干涸湖底梭梭种群Ⅰ、Ⅱ、Ⅲ径级个体数占所有径级个体总数的63.38%,存在一定数量的大径级个体,该种群发育历史较长,种群处于稳定阶段。格局分析表明,在不同生境条件下,梭梭种群均呈聚集分布。在梭梭种群的不同发育阶段,随径级的增大,种群分布由聚集分布向随机分布或均匀分布发展。总体来看,不同生境条件下梭梭种群年龄结构和空间分布格局差异明显。这是种群发育历史、物种特性、环境、干扰等因素综合作用的结果。

Population age structure and spatial pattern are central issues in population ecology.In this study,Haloxylon ammodendron populations in two typical habitats along northwestern edge of Junggar basin were investigated.Using data collected from 0.75-hm2 plots,we determined the diameter class structure,static life table,survival curves and spatial distribution pattern of the two populations to analyze the distribution characteristics of Haloxylon ammodendron population in this reign.It was found that the diameter class structure of the two Haloxylon ammodendron populations were significantly different.Most individuals(96.21%) of population in piedmont Gobi were concentrated in theⅠ,Ⅱ,Ⅲ diameter classes.No individuals were in Ⅷ,Ⅸ,Ⅹ diameter classes.This population had a short development time and it was in the growing period.A lot of individuals(63.38%) of the population in the bottom of the dry lake were in theⅠ,Ⅱ,Ⅲ diameter classes and some(9.39%) were in Ⅷ,Ⅸ,Ⅹ diameter classes.We hold that the population had a longer development time and it was in the stable period.Spatial pattern analysis showed that the Haloxylon ammodendron populations in different habitats appeared clump distribution.And at different developmental stages,with the increase of the diameter classes,the distribution pattern changed from clump to random or even.The results indicated that significant differences of population structure and spatial distribution pattern were found between Haloxylon ammodendron populations in different habitats.It was the synthesis effect of population history,species traits,environmental conditions and disturbance.