湖北宣恩七姊妹山天师栗(Aesculus wilsonii)群落特征

ON THE COMMUNITY CHARACTERISTICS OF AESCULUS WILSONII AT THE QIZIMEI MOUNTAIN IN XUAN'EN,HUBEI PROVINCE

天师栗(Aesculus wilsonii)是我国特有的珍稀树种,其天然分布比较零散,极少有大面积的自然群落存在。对湖北宣恩七姊妹山天然分布的天师栗群落采用相邻格子法进行调查,研究了群落的物种多样性、空间格局、群落结构和种群径级结构等群落特征。结果表明:(1)天师栗是群落的主要优势树种,其重要值为22.7,远大于重要值排在第二位的红枝柴(重要值为13.7),且在群落中呈聚集分布类型;(2)群落物种比较丰富,相对于灌木层和草本层,乔木层丰富度指数和均匀度指数较低,优势度指数较高,说明乔木层物种没有灌木层和草本层多,且分布不均匀,但优势种作用显著,成层现象明显;(3)群落的年龄结构显示,该群落虽然目前处于稳定阶段,但群落中5个优势种群的幼年个体补充都严重不足,潜在的影响群落以后的生存和发展。应采取保护措施,促进群落的自然演替。

Aesculus wilsonii, a rare tree species and endemic to China, usually sporadically distributes in the evergreen and deciduous broad-leaved mixed forest in China, and there are very few natural Aesculus wilsonii communities with considerable area in the nature. In the present study, the biodiversity, space distribution pattern, size class of population and community structure of an infrequent natural Aesculus wilsonii community,which was found at the Qizimei Muontain in Xuan＇en of Hubei Province,were analyzed by using the methods of community ecology and contiguous grid. The results showed that. （1） Aesculus wilsonii was a dominant species in the community,and its importance value was 22.7,far larger than that of Meliosma oldhamii, whose importance value was 13.7 and was the second largest one in the community; （2） Species in the community were very abundant. Abundance index and evenness index of the tree layer were much lower than those of the shrub layer and the herb layer, while dominance index of the tree layer was far larger than that of the shrub layer and the herb layer, which illuminated that the species in the tree layer were fewer than in the shrub layer and the herb layer. In addition,most of the dominant populations displayed an uneven distribution pattern,and the role of the dominant species in the tree layer was marked and the stratification was evident in the Aesculus wilsonii community; （3） According to the age structure, Aesculus wilsonii community was presently stable, but the seedlings and saplings of all the five dominant populations were severely insufficient in the Aesculus wilsonii community, which would make the community considerably susceptible to the potential influences on its survival and development. As a result, some measures should be taken to protect the community.