岩溶区不同母岩植物群落物种组成及优势种群生态位差异

Species composition and niche differences of dominant populations of plant communities from different parent rocks in karst area

以广西平果市纯石灰岩、石灰岩夹白云岩天然次生林为研究对象,在野外群落调查基础上,应用Levins生态位宽度和Pianka生态位重叠指数进行优势种群生态位特征分析。结果表明:纯石灰岩生境下调查到维管植物56种,隶属于35科45属,石灰岩夹白云岩生境下调查到维管植物44种,隶属于33科42属。两种生境下桑科(Moraceae)物种丰富度均占有明显优势,主要为榕属及波罗蜜属。豆科(Leguminosae)、荨麻科(Urticaceae)、楝科(Meliaceae)植物在纯石灰岩生境占优势;大戟科(Euphorbiaceae)植物在石灰岩夹白云岩生境下占优势,群落总体相似性较低。乔木层植物蚬木(Excentrodendron hsienmu)、灌木层植物葡萄叶艾麻(Laportea violacea)与草本层植物肾蕨(Nephrolepis cordifolia)为两种母岩生境植被中的共有物种且生态位宽度指数较高。纯石灰岩森林乔木层与灌木层优势种生态位完全不重叠种对数量较石灰岩夹白云岩森林高14对,纯石灰岩森林乔木、灌木物种相对丰富。在岩溶区进行植被恢复建设中,应依据不同岩性背景优先选择生态位宽度较宽的物种作为先锋树种,同时考虑与其生态位重叠指数低的树种作为伴生种,避免植物不适宜生长或生态位功能冲突。

The landform of Pingguo City,Baise City,Guangxi Zhuang Autonomous Region,belongs to the typical peak cluster type in the karst area of southwest China.Pure limestone is the main local lithology,and limestone with dolomite is one of the more common lithologies in Pingguo City.Studying the species composition and niche differences of karst forest communities under different lithological backgrounds will help to understand the resource utilization of various plant groups under different lithological conditions.At the same time,it will be useful for scientifically formulating the vegetation restoration plan for stony desertification control in this area.It is of great significance.Taking natural secondary forests of pure limestone,limestone and dolomite in Pingguo City,as the research object,through the preliminary investigation,a total of 6 sample plots of 30 m×30 m were set up in typical areas of pure limestone and limestone with dolomite in Pingguo City.Based on the field community survey,the Levin niche width and Pianka niche overlap index were used to analyze the niche characteristics of dominant populations.The results showed that 56 species of vascular plants were investigated in the pure limestone habitat,belonging to 35 families and 45 genera,and 44 species of vascular plants were investigated in the limestone-dolomite habitat,belonging to 33 families and 42 genera.The species richness of Moraceae had obvious advantages in the two habitats,mainly Ficus and Artocarpus.Legumes,Urticaceae,Meliaceae plants dominate in pure limestone habitats;Euphorbiaceae plants dominate in limestone-dolomite habitats,and the overall community similarity was low.The tree layer plant Excentrodendron hsienmu,the shrub layer plant Laportea violacea and the herb layer plant Nephrolepis cordifolia were the common species in the vegetation of the two parent rock habitats and had a high niche breadth index.The number of dominant species in the pure limestone forest arbor layer and the shrub layer did not overlap at all.The number of species pairs was 14 higher than that in the limestone dolomite forest.The pure limestone forest was relatively rich in species of trees and shrubs.During the restoration of vegetation in karst areas,species with higher niche width should be preferentially selected as pioneer tree species based on different lithological backgrounds,and tree species with low niche overlap should be considered as companion species to avoid unsuitable growth of plants or conflicts in niche functions.