人为干扰对福建建瓯常绿阔叶林空间结构的影响

Effects of human disturbance on the spatial structure of the evergreen broad-leaf forest in Jianou city of Fujian Province

人为干扰是引起常绿阔叶林生态系统结构和功能变化主要因素.以位于福建建瓯万木林自然保护区保护完整的常绿阔叶林(C)和地处同镇,光照、降雨、土壤、气温等自然环境因子基本一致,但曾受人为严重破坏的两处常绿阔叶林(人为干扰群落,D)为对象,分析人为干扰对建瓯市常绿阔叶林群落空间结构的影响.研究发现,群落垂直空间结构方面,人为干扰主要破坏了群落垂直结构的上层,进而导致整个群落垂直结构的变化.对群落水平结构的分析表明,经过封山育林,D群落正向C群落演替.以米槠(Castanopsis cariesii)种群为代表对建瓯常绿阔叶林在人为干扰下种群分布格局的变化进行的初步研究表明两群落米槠种群均为聚集分布,且各项聚集强度指数无显著差异.虽然D群落中米槠重要值相对较低,在人为砍伐后的群落恢复过程中,由于较强的生态适应性和根桩萌蘖能力,从而仍具有较高的聚集度.

The analysis about the forest community characteristics might throw a light upon the understanding to the effects of human-caused disturbance on forest ecosystem. Based on the investigation to two kinds of communities which included three conserved forest communities in Wanmulin Nature Reserve （C） in Fangdao town of Jianou city of Fujian province and four human-caused disturbed forest communities（D） in the same town and hereby with a similar ecological environment, we analyzed the effects of human-caused disturbance on the community spatial structure characteristics of evergreen broad-leaf forest in Jianou city of Fujian province. For the vertical structure of the communities, it could be ascribed mainly to the destruction of the upper communities of D that the whole vertical structure affected by the humancaused disturbance. The analysis to the level structure showed that D seemed to be evolving to the type of C. The effects of human-caused disturbance on the spatial pattern of population in the communities were analyzed preliminarily with a view to Castanopsis cariesii. The distributive pattern of both populations in C and D belonged to clumpy distribution, and there is not remarkable difference on the aggregative indexes between both of the populations. Although the importance value of Castanopsis cariesii in D is lower, the species was highly aggregative because of its nice ecological adaptability and the intensely asexual germination of its stump roots.