极小种群广西青梅群落物种及空间结构特征

摘要

A small population Vatica guangxiensis in Guangxi Laohutiao Natural Reserve was investigated to explore its woody species composition by analyzing community spatial parameters including mingling indexes , uniform angle and size ratio . The communities contained 432 trees, 45 woody species, 38 genera and 27 families;where Aidia canthioides had the most numbers of tree , second by V.guangxiensis.Among the canopy layer (>20 m) , V.guangxiensis and Canarium album were dominant;while in the cohort of DBH>30 cm, V.guangxiensis, C.album and Cyclobalanopsis lamellosa were superiors. Average mingling index of the stands was 0.88.Except for A.canthioides, which was weakly mingled , other species were highly to extremely mingling .A majority of the stands were randomly or unevenly distributed , and few stands were evenly distributed.Average uniform angle of the stands was 0.69 with mild clumped distribution .The distribution frequency of trees of different sizes fluctuated mildly .The forests were highly differentiated with the average size ratio of 0.36.C.album, Chukrasia tabularis and Cyclobalanopsis fleuryi were dominant in their units , and all the others were subordinates .%以广西老虎跳自然保护区全面调查数据为基础。利用混交度、角尺度和大小比数等结构参数，分析广西青梅的群落空间结构特征。结果表明：广西青梅的群落木本植物共有45种，隶属于27科38属432株；香楠林木数量最多，广西青梅次之。树高≥20 m的上层乔木，以广西青梅、橄榄占优势；胸径≥30 cm以上的乔木以广西青梅、橄榄、薄片青冈为优势。群落林分混交度均值为0．88，林分处于强度混交水平；香楠以零度混交和弱度混交为主，其余的树种均以强度混交和极强度混交为主。林分中大部分林木介于随机分布和不均匀分布之间，均匀分布极少，角尺度均值为0．69，空间分布格局为轻度团状分布。群落林分不同径级的林木在空间结构单元内分布频率相差不大，林木分化程度较高，林分大小比数均值为0．36，其中林木数量较多的橄榄、麻楝和饭甑青冈在各自种群结构单元中为优势木，其它树种优势度不明显。