湖北兰科植物多样性及其区系地理特征

Diversity and floristic characterics of Orchidaceae in Hubei

关键词:  兰科, 多样性, 植物区系, 分布格局, 湖北

Key words:  Orchidaceae, biodiversity, flora, distribution pattern, Hubei

摘要:

湖北植被尤其是鄂西地区,在近代以来备受植物学家的关注。该研究基于植物标本、文献资料与野外调查成果,整理出湖北兰科植物名录,结合湖北的地形与气候特征分析了湖北兰科植物的分布格局、区系及多样性特征。结果表明:湖北兰科植物主要分布在西南、西北、东北及东南部山区,以鄂西山地最为丰富,中南部江汉平原最少,900～1 200 m中海拔地段丰富度最高; 物种多样性由南至北、由西至东呈递减趋势,鄂西南与鄂西北之间具有最大相似性; 除拟兰亚科(subfam. Apostasioideae)外的5个亚科湖北均有分布,计有15族54属141种,单种属和寡种属分别占总属数的50.00%和33.33%; 湖北兰科植物东亚分布成分占40.43%,中国特有种占总种数的41.84%,东亚区系主体突出,中国特有成分所占比例较大,其中中国—日本成分占优势; 温带属性较强,亚热带向温带过渡特征明显,有25个热带分布属及27个温带分布属,热温比为0.93,种级水平的热带分布类型占8.51%,温带分布类型占91.49%; 一些稀缺种在台湾与湖北的间断分布,表明两者植物区系有较强的关联性; 湖北兰科植物区系与西南及横断山区联系密切,是与东部地区植物区系交流的中转站。

Abstract:

Vegetation of Hubei is a hotspot of biology study, especially in the western mountains, which is a center of biodiversity in China. On the basis of specimen data, literature and field survey findings, a list of the Orchidaceae in Hubei was developed. The characteristics of the Orchidaceae distribution pattern in Hubei, geographical flora and diversity were analyzed, based on the topographic and climatic features of Hubei. Orchidaceae in Hubei is distributed mainly in southwest, northwest, northeast and southeast mountain areas. Its diversity is the highest in western mountains especially in the areas at the altitude of 900 - 1 200 m while the lowest in Jianghan Plain in central South Hubei. Generally the species richness decreases from the west to the east and from the south to the north. The diversity similarity between southwest and northwest mountains is the highest. There are 141 species, belonging to 54 genera, 15 subtribes, and 5 subfamilies except for subfam. Apostasioideae. Overall, 50.00% of the genera are monotypic, and 33.33% are oligotypic. The florescence is mainly in April to September, and July is the peak of flowering. Among all the species found in Hubei, 40.43% are East-Asian species, and 41.84% are endemic to China. Twenty-five genera are tropical, meanwhile 27 are temperate, with a ratio of 0.93. The tropical species account for 8.51%, and the temperate species account for 91.49%. The study showed that among the Orchidaceae in Hubei, the Eastern Asian flora was the main part, and the Sino-Japanese type was dominant. At the same time, Orchidaceae in Hubei showed high temperate attribute and significant characteristics of the transition between the sub-tropics and the temperate zone. The disjunctive distribution of some rare species in Hubei and Taiwan of China indicates a considerable correlation between the flora of the two areas. Hubei is closely related to Southwest China and the Hengduan mountains in respect of the Orchidaceae flora, and Hubei is the transitional area for the flora exchange with the East China.