中国特有种丹霞梧桐白湾新分布群落特征研究

Baiwan New Distribution Community Characteristics of Firmiana danxiaensis, an Endemic Species of China

关键词:  丹霞梧桐  喀斯特地貌  新分布  物种组成  地理成分

Key words:  Firmiana danxiaensis  karst landform  new distribution  species composition  geographical elements

摘要:

中国特有种丹霞梧桐（Firmiana danxiaensis）是国家二级重点保护野生植物，本研究团队在广东省清远市清新白湾省级自然保护区踏查时发现丹霞梧桐的新群落分布（后文统称为白湾群落）。为了解丹霞梧桐在石灰岩地貌上的群落结构与种群特征，采用样方法进行调查，并对比分析不同地貌及不同分布点间的丹霞梧桐的群落特征。结果表明：（1）在研究的12个群落中共记录到30科36属38种植物，其中蕨类植物种类少，未发现裸子植物，被子植物占绝对优势，种子植物以热带成分为主，泛热带和热带亚洲成分次之。（2）11、12、6和3号样方为丹霞梧桐分布数量最多的4个群落。丹霞梧桐群落的年龄结构呈稳定型，其在乔木层的生长优势大于灌草层。（3）与丹霞山、南雄和英德的丹霞梧桐群落相比，白湾丹霞梧桐群落的物种丰度更低，种子植物地理区系成分构成相似，丹霞梧桐平均高度和平均胸径均高于丹霞山群落，低于南雄鸳鸯湖群落。目前，白湾群落的丹霞梧桐生长状态良好。为科学保护，建议将此群落设为丹霞梧桐就地保护小区，并将11、12、6和3号样方作为重点进行持续稳定监测。

Abstract:

Firmiana danxiaensis is a national key protected plant of ClassⅡ, and endemic to China.A new concentrated distribution of F.danxiaensis was found based on the field survey in Baiwan Provincial Nature Reserve in Qingyuan City, Guangdong province. In order to understand the community structure and population characteristics of F.danxiaensis in limestone landscapes, we used sample methods to investigate and comparatively analyze the community characteristics of F.danxiaensis in different landscapes and among different distribution points.The results showed that:(1) A total of 38 vascular plants were recorded among 12 plots, which belong to 30 families and 36 genera.The angiosperms are absolutely dominant, with barely few ferns but no gymnosperms;and the seed plants are dominated by the tropical components, followed by the pantropical and tropical Asian components.(2) Plots 11, 12, 6, and 3 are the top 4 communities with the highest number of F.danxiaensis.The age structure of community is stable, the growth advantages of F.danxiaensis in the tree layer is greater than that of shrub and grass layer, respectively.(3) The species abundance of F.danxiaensis community in Baiwan distribution point is lower than that of Danxia Mountain, Nanxiong and Yingde.The floristic geographical elements are similar.In terms of height structure and diameter at breast height, the Baiwan communities of F.danxiaensis are both higher than Danxia Mountain communities, while lower than Nanxiong Yuanyang Lake communities.In summary, the F.danxiaensis grows well in Baiwan new distribution point, which provides resources for its conservation study.It is suggested that this new concentrated distribution point of F.danxiaensis should be set as a in situ protected district with continuous and stable monitoring system, which plots 11, 12, 6, and 3 as focus.