外马廊山岛植被特性与植物多样性

Vegetation characteristics and plant diversity of Waimalangshan Island, Zhoushan

关键词:  无居民海岛, 海岛植物, 生活型结构, 地理成分, 群落结构, 植物多样性

Key words:  desert island, island plants, life form, geographical elements, community structure, plant diversity

摘要:

该研究对无居民海岛舟山外马廊山岛进行初步踏勘,了解该岛植被特征与植物多样性,探讨海岛植被与大陆植被的差异性,并对海岛植物的主要植物组成、生活型结构、地理成分、群落类型以及多样性和相似性进行了分析。结果表明:外马廊山岛面积小,共有33科51属55种植物,植物种类偏少,留存有普陀狗哇花,滨柃,厚叶石斑木等具有滨海特色植物,具有开发潜力。外马廊山岛热带成分较为明显,与附近地区较为相似。岛上群落优势种或建群种的科为山茶科,大戟科,松科等,与大陆的常绿阔叶林的优势种或建群种的优势科如樟科,金缕梅科,壳斗科,山茶科等不大相同。岛上植物主要以高位芽植物为主(58.18%),但较大陆常绿阔叶林的高位芽植物比例要低。外马廊山岛植物群落结构简单,植物多样性相对较低,物种丰富较低,主要原因在于生态适应性和演替过程的差异,岛上植物群落演替至稳定群落还需要相当一段时间。外来种比例占9.09%,外来种如黑松和红鸡竹能形成群落或在群落中具有较为明显的优势,并可能会造成一定的生态干扰。

Abstract:

The vegetation characteristics and the ɑ, β biodiversity of plant commnuties were investigated at the desert island of Waimalangshan Island, Zhoushan Archipelago, Zhejiang Province. In order to discuss the difference of vegetation characteristics and plant diversity between Waimalangshan Island and nearly mainland, we analyzed the vegetation characteristics, life form of island plants, geographical elements, similarity of six plant communities, the structure and diversity of community. Firstly, there were 55 species of seed plants belonging to 33 families 51 genera in Waimalangshan Island. The area of Waimalangshan Island is small, but there existed some autochthonal strand plants such as Heteropappus arenarius, Eurya emarginata, Rhaphiolepis umbellata, which had great development potentials in landscape use. Secondly, the tropical types of genera were distinct similar to nearly islands, Dongfushan Island and Dajinshan Island. The families of dominant species in communities were Theacea, Pinaceae Euphorbiaceae, nevertheless, it was different from the zonal vegetation's dominant families in island forest. The major life form was phanerophytes plants of island plants and the proportion in plant life form were lower than that in the life form of subtropical vegetation. Thirdly, the richness and structure of plant population were simple and contained less diversity than the nearly mainland due to small area and special circumstance. Margalef richness, Simpson diversity, Shannon-Wiener diversity, Pielou evenness of tree layers were higher than that of shrub's layer. The dominant species of tree and shrub's layer was single. Similarity of six plant communities were low ranging from different habitats because of high level of landscape fragmentation. Because of the difference of ecological adaptability and stage of plant succession, the plant population would take a long time to be climax community. Lastly, the proportion of introduced plants of Waimalangshan Island plants was 9.09%. Pinus thunbergii and Phyllostachys mannii which were introduced species for landscape use had a distinct dominance in plant communities for several decades. Native plants loss, introduced plants increased and native plants disappeared. It should be treated with caution that introduced plants may caused eco-disturb to native plants for competitive relationship in habitat fragmentation.