西双版纳片段化石灰岩森林附生兰科植物多样性研究

西双版纳石灰岩地区拥有丰富的兰科植物资源,但近年来随着橡胶树的大面积种植,使得该地区很多石灰岩森林呈片段化。为了解片段化石灰岩森林中附生兰科植物多样性状况以及片段化对附生兰科植物的影响,该研究选取了生境片段化的青岩寨和曼纳览,以及连续生境的绿石林和巴卡新寨等4个样地的29个样方进行多样性调查和对比研究。结果表明:4个石灰岩森林样共记录到附生兰科植物34属76种1 528株(丛)。通过对坡向、坡度、海拔、地形、郁闭度和森林类型等6个环境因子与附生兰科植物丰富度进行CCA分析,发现石灰岩地区附生兰科植物的分布主要受海拔和森林类型2个因素的影响,在海拔较高的青岩寨和巴卡新寨附生兰科植物物种丰富度高于低海拔的绿石林和曼纳览,而片段化对附生兰科植物的物种多样性和多度均无显著影响,这可能与片段化的历史较短有关。虽然目前来看生境片段化对石灰岩地区的附生兰科植物多样性无显著影响,但生境脆弱的石灰岩森林植被的保护对于兰科植物多样性保护则更具重要性。

Diversity of epiphytic orchids in fragmental limestone forests in Xishuangbanna, China

There are abundant orchid species in tropical limestone forests in Xishuangbanna. Many are fragmented due to recent large-scale cultivation of rubber trees in the area. The aim of this study is to explore the diversity of epiphytic orchids in fragmented limestone forest and the effects of habitat fragmentation. We established 29 of plots 15 m² in 4 tropical limestone forests,and recorded a total of 1 528 individuals of epiphytic orchids belonging to 76 species and 34 genera using Canonical Correspondence Analysis with species richness and abundance, and with aspect, slope, elevation, topography, canopy density and forest types as environmental factors. We found that the distribution of epiphytic orchids in limestone forests was affected by altitude and forest type significantly. Species richness of epiphytic orchids in higher elevations, Qingyan Village and Baca Village, was higher than Greenstone rain forests and Mannalan in low elevations. Habitat fragmentation had no effect on the diversity and abundance of epiphytic orchids in tropical limestone rain forests which might be fragmented on a short temporal scale. Regarding our findings, protecting harsh limestone forest habitats is highly important for the protection of orchid diversity.