海南主要陆域自然保护地兰科植物多样性与生境的关联分析

Association analysis of orchid diversity and habitat in main land nature reserves in Hainan

为了掌握海南主要陆域自然保护地内野生兰科植物的物种多样性现状以及制约其发展的关键生境因子,对该地区进行兰科植物资源调查并分析兰科植物多样性的空间分布格局,进一步采用典范对应分析(CCA)探索生境因子对兰科植物组成的影响,最后运用广义线性模型(GLM)框架下的负二项回归拟合兰科植物丰富度和多度对生境变异的响应。结果表明:(1)共发现兰科植物67属193种,为海南兰科植物分布的绝对中心。(2)水平方向上,霸王岭兰科植物丰富度高但居群相对拥挤,而五指山最大的海拔落差带来了更加多样化的小生境类型和宽阔的生存空间,孕育了种类丰富且分布均匀的兰科植物资源。(3)垂直方向上,中海拔地区兰科植物种类最为丰富且种间竞争较为激烈,高海拔地区则存在明显的优势类群。(4)海拔变化对兰科植物物种组成变异有着非常高的解释率,而喀斯特和河谷地貌的显著影响也不容忽视。(5)多因子综合作用共同影响着兰科植物的多样性,其中坡度、河谷地貌、喀斯特地貌的显著正效应和枫香林的显著负效应受其他协变量的影响较小,是驱动兰科植物丰富度和多度变化的关键生境因子。综上所述,中高海拔地区以及特殊地貌(如河谷和喀斯特地貌)应作为兰科植物多样性的优先保护区域。

To grasp the current status of orchid diversity in main land nature reserves in Hainan and the key habitat factor restricting their development,conducted an investigation of orchid resource in the study area and analyzed the spatial distribution pattern of orchid diversity,the canonical correspondence analysis(CCA)was used to explore the influence of habitat factors on the composition of orchid,and finally the negative binomial regression under the framework of generalized linear model(GLM)was used to fit the response of the richness and abundance of orchid to habitat variation.The results are as follows:(1)A total of 193 species in 67 genera of orchids are found in the study area,which is the absolute center of the distribution of orchid in Hainan.(2)In the horizontal direction,Bawangling has high richness of orchid but relatively crowded population,while the largest elevation difference in Wuzhishan brings more diversified niche types and wide living spaces,giving birth to a rich and even distribution of orchid.(3)In the vertical direction,orchids are the most rich in mid-elevation area and the inter-species competition is fierce,while high-elevation area have obvious dominant groups.(4)The elevation factor has a very high explanatory rate for the variation of orchid composition,and the significant influence of karst and river valley landform can also not be ignored.(5)The comprehensive effect of multiple factors affects the diversity of orchid,among them,the significant positive effect of slope,valley landform,and karst landform and the significant negative effect of Liquidambar formosana forest are less affected by other covariate,which is the key habitat factor that drives change in the richness and abundance of orchid.In summary,middle and high elevation areas and special landforms(such as river valley and karst)should be considered as priority protection area for orchid diversity.