几种不同生境条件下天然沙冬青种群分布格局与特征

Distribution pattern and characteristics of Ammopiptanthus mongolicus in several different habitat conditions

通过对甘肃境内三种不同生境条件下的天然沙冬青种群的野外调查,对其种群特征、年龄结构及分布格局进行了对比分析。结果表明:1)三种生境的天然沙冬青种群分布格局及特征差异明显。石质山坡阳坡的平均密度、高度、冠幅、分枝数均高于阴坡面的;固定沙地沙冬青种群平均密度较小,但受到风吹沙埋的影响,分枝数较多。2)石质山坡阳坡和阴坡沙冬青个体主要是幼树,属于稳定型种群,但天然更新困难,几乎没有幼苗,缺乏后备资源,极有可能衰退;固定沙地沙冬青个体主要是老龄树,没有幼苗,种群已经出现了明显的衰退,属于衰退型种群。3)沙冬青种群的生境主导了种群的分布格局,石质沙坡阳坡和固定沙地沙冬青种群呈均匀分布,石质山坡阴坡沙冬青种群呈集群分布。

By the comparative study of the characteristics,age structure and distribution pattern of Ammopiptanthus mongolicus in three different habitat conditions,we got the results that：1） The average density,height,crown and branches of the natural A.mongolicus growing in sunny slope are higher than that growing in shade side of rocky slope;The average density of the plant which growing in fixed sand is smaller,but due to the effection of wind and sand buried,the number of branches are more.2）The main individual growing in rocky slope are young and stable,but the natural regeneration is difficult,there are little seedlings,lacking of reserve resources will be most likely recession;The main individuals growing in fixed sand are old and has no seedlings,they has been declining significantly.3） The habitat conditions of the plants lead to the distribution pattern.The plants growing in sunny rocky slope and fixed sand appear uniformly distribution,while that in shade side of rocky slope appear cluster distribution.