摘要
由于独特的地理和气候条件,中国兰科植物具有附生与地生种类数目大致相同的特点,同时是世界上地生兰科植物种类最丰富的地区。因此,地生兰科植物的保护是中国兰科植物保护的重要内容,而确定多样性中心对制定就地保护策略具有重要意义。四川黄龙寺自然保护区内的黄龙沟长仅3.5km,海拔为3100–3569m。通过对沟内兰科植物种类、生境、居群状况以及繁殖情况等的综合调查,我们发现该地共有兰科植物19属30种。这些兰科植物生长于明显不同的两类生境:一是林分稀疏、透光性好的疏林或灌木丛,通常有钙华滩流贯穿其中,有20种兰科植物生长;二是林分较密、透光性差的针阔混交林或针叶林,无水流,只有10种兰科植物分布,包括黄龙沟内仅有的4种腐生兰。黄花杓兰(Cypripediumflavum)、西藏杓兰(C.tibeticum)、无苞杓兰(C.bardolphianum)、广布红门兰(Orchischusua)、二叶红门兰(O.diantha)及少花虾脊兰(Calanthedelavayi)等3属6个种,以其极高的数量及成片的分布组成黄龙沟兰科植物的主体。它们在种下水平存在不同程度的变异,而且花期存在重叠与交替现象。如此多的地生兰聚集在一条狭窄的沟内,并且部分种类在沟内形成优势草本群落,这种现象无疑是十分罕见的。可以说黄龙沟是我国地生兰多样性中心之一。
China has rich terrestrial orchid resources, with the number of terrestrial orchid species equal nearly to that of epiphytic orchids. From a conservation perspective, the Chinese terrestrial orchids deserve considerable attention. Considering the huge areas of the temperate zone and alpine mountains of China, where most terrestrial orchids are distributed, and the different abundance of terrestrial orchids in different areas and different habitats, it is important to identify “hotspots” for the conservation of the Chinese terres- trial orchids. Huanglong Valley, at an elevation of 3100–3569 m and only 3.5 km long, is the main landscape feature of Huanglong Nature Reserve, Sichuan, China. It is also the largest travertine region in the world. In this narrow valley rich terrestrial orchid diversity was found: a total of 30 orchid species in 19 genera were found in the valley, all of which were terrestrial orchids, including 4 saprophytic orchids. These orchids grew in two different habitats: one was open shrub and forest margin with travertine stream flows, where 20 orchid species occurred; another was relatively dense mixed coniferous broad-leaved forest without water flows, where 10 orchid species were found. Cypripedium flavum, C. tibeticum, C. bardolphianu, Orchis chusua, O. diantha and Calanthe delavayi were the main orchid species found in Huanglong Valley with abundant indi- viduals. The florescence times of these terrestrial orchids overlapped because of the short growing season of the alpine mountains. However, there were rich intraspecific variations in floral morphology in some orchid species. Huanglong Valley could be considered one of the terrestrial orchid “hotspots” in China, and even in the world. We believe our study results could supply basic data for generating specific management strate- gies, long-term monitoring and study of terrestrial orchids in Huanglong Valley.
出处
《生物多样性》
CAS
CSCD
北大核心
2005年第3期255-261,共7页
Biodiversity Science
基金
国际科技合作重点项目计划(2001CB711103)
