濒危植物篦子三尖杉的群落特征

The Community Characteristics of Endangered Species Cephalotaxus oliveri Mast

研究了云南、贵州和江西自然分布的8个篦子三尖杉群落。群落共有微管属植物108科,235属,336种。篦子三尖杉在群落中是主要层的共优种或伴生种,但随着生境条件不一致,这些篦子三尖杉生长地的植物群落类型也各不相同。群落组成上以樟科和蔷薇科等为主要优势科,山胡椒属和荚蒾属等属为主要优势属,伊桐、灯台树、木姜子、八角枫、短梗大参、大叶方竹、毛竹等是主要优势种;群落外貌特征同亚热带常绿阔叶林近似,生活型组成以高位芽植物为主,高位芽植物(Ph.)、地上芽植物(Ch.)、地面芽植物(H.)、隐芽植物(Cr.)和一年生植物(Th.)分别占62.78%、12.67%、9.73%、12.29%和2.53%。叶级以微型叶为主(68.49%),无大型叶和巨型叶。叶质以纸质叶所占比例最大(55.89%),膜质叶最小(4.93%)。叶型以单叶为主(76.99%),全缘叶和非全缘叶近相等;从群落结构上看,8个群落的乔灌木个体在水平空间均呈集群分布状态,而群落以高于3.5 m以上的层次在群落中占优势,平均盖度为68.71%。从目前的静态生命表看,道真县、江口县、台江县、镇远县的篦子三尖杉种群属于增长型种群,而芦溪县、凯里市、屏边县和新平县的种群属于稳定型种群;此外,不同群落之间具有物种多样性水平明显不同,群落之间的共有种少,相似程度较低等特点。

Applying the phytosociological methods,eight communities of Cephalotaxus oliveri distributed in Yunnan,Guizhou and Jiangxi provinces were investigated.The results showed that there were 336 species of vascular plants belonging to 235 genera of 108 families,and generally,Cephalotaxus oliveri has became common dominant or frequent species in the dominant layer of these communities.Lauraceae was the most dominant family,Lindera was the most dominant genus,and Itoa orientalis,Bothrocaryum controversa,Litsea pungens,Alangium chinense,Macropanax rosthornii z Chimonobambusa grandifolia and Phyllostachys heterocycla（Carr.） Mitford cv.＂Pubescens＂were the main dominant species in the community composition.The community physiognomy of Cephalotaxus oliveri was very similar to that of Subtropical evergreen broad-leaf forest,according to Raunkiaer＇ life form system,the ratios of phanerophytes,chamaephytes,hemicryptophytes,cryptophytes and therophytes were 62.78%,12.67%,9.73%,12.29% and 2.53% respectively.The study of leaf types indicated that the compositions of leaf was made up for nanophyll of 68.49%,without macrophyll and megaphyll.For leaf texture,the papery leaf took the largest proportion（55.89%） and that of membranous leaf the least（4.93%）.The proportion of simple leaves was 76.99% and that of compound leaves was 23.11%,the entire leaves took 49.04% and no-entire leaves took 50.06%.And the spatial pattern of individual distribution in all communities belonged to be clumped.The characteristics of vertical structure of communities indicated that the layer higher than 3.5m,with 68.71% of mean value of coverage,was the dominant layer in the communities.Also the statistics of static life table explained that the populations growing in Daozhen,Jiangkou,Taijiang and Zhenyuan counties belonged to expanding populations,but the populations in Luxi,Kaili,Pinbian and Xinping counties were stable populations.In addition,the species diversity in different communities also existed significant