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广西极小种群单性木兰群落空间结构量化

彭玉华1,2,何琴飞1,2,谭长强1,2,申文辉1,2*,覃文更3,何峰1,2   

  1. 1广西林业科学研究院, 南宁 530002; 2广西优良用材林资源培育重点实验室, 南宁 530002; 3木论国家级自然保护区管理局, 广西环江 547100)
  • 出版日期:2016-02-10 发布日期:2016-02-10

Quantitative analysis of stand spatial structure of a rare species Kmeria septentrionalis in Guangxi.

PENG Yu-hua1,2, HE Qin-fei1,2, TAN Chang-qiang1,2, SHEN Wen-hui1,2*, QIN Wen-geng3, HE Feng1,2   

  1. (1Guangxi Forestry Academy, Nanning 530002, China; 2 Guangxi Key Laboratory for Elite Timber Cultivation, Nanning 530002, China; 3Administrative Bureau of Mulun National Nature Reserve, Huanjiang 547100, Guangxi, China)
  • Online:2016-02-10 Published:2016-02-10

摘要: 在木论自然保护区极小种群单性木兰(Kmeria septentrionalis)群落木本植物每木调查的基础上,采用混交度、角尺度和大小比数3个林分空间结构参数,分析单性木兰生存群落木本植物物种组成及其空间结构特征。结果表明,样地内共有木本植物树种95种,隶属于55科82属,为典型的阔叶混交异龄林。群落林木以小径级占绝对优势,林木个体随着径级的增大急剧减少,整体呈倒J型分布。群落中大部分树种处于强度混交,树种间混交程度较高,林分平均混交度达0.742;群落林分大小比数为0.508,不同等级的林木在空间结构单元内分布较均匀;大部分林木介于随机分布和不均匀分布,均匀分布比例较少,林分平均角尺度为0.549,群落空间分布格局为轻度聚集分布。单性木兰种群径级结构呈倒J型,种群从幼苗向幼树生长过程中林木个体急剧减少。单性木兰种群混交度为0.796,处于高度混交状态;平均大小比数为0.400,处于亚优势偏向中庸状态;角尺度为0.528,呈轻度聚集分布状态。单性木兰群落不仅亟须有效保护,同时需采取适当的人为干扰措施促进种群的延续与发展。

关键词: 氮矿化速率, 丹江口库区, 土层, 覆膜土壤

Abstract: Three stand spatial structure parameters, including mingling degree, uniform angle and size ratio, were used to analyze species compositions and spatial structure patterns of a rare species Kmeria septentrionalis community in Mulun Reserve, Guangxi. The result showed that the community included 95 woody species, belonging to 55 families, 82 genera, being a typical unevenaged mixed broadleaf forest. The community was dominated by small DBH individuals, and tree numbers decreased as DBH increased, presenting an inverse J shape distribution. In the community, a majority of trees were strongly mingled (with an average mingling degree 0.742), and the size ratio was 0.508. Trees with hierarchical DBHs were evenly distributed in spatial structure, and most trees were of random to uneven distribution (with an average uniform angle 0.549), representing a mild aggregation. K. septentrionalis’ DBH structure also presented an inverse J shape, with decreased individuals in the process from seedlings to young trees. K. septentrionalis population had high mingling degree (0.796), moderate size ratio (0.400) and weak aggregated distribution (uniform angle 0.528). In sum, efficient conservation and appropriate human interference efforts are needed for a sustainable K. septentrionalis population.

Key words: soil layer, Danjiangkou Reservoir area., nitrogen mineralization rate, mulching soil