福建平潭大练岛典型森林群落特征及物种多样性

Characteristics and species diversity of typical forest community in Dalian island of Pingtan,Fujian,China

为揭示福建平潭大练岛典型森林群落特征及生态学意义,向大练岛森林植被的更新演替、恢复及可持续性发展提供参考,应用样方法对其植被类型、物种组成、区系特征、植物功能性状和物种多样性进行调查分析,并用冗余分析法分析群落物种多样性与环境因子的相关性.结果表明:(1)在18个样方中,共记录到维管束植物65科151属178种,种子植物科、属的R/T值(热带分布的科或属数与温带分布的科或属数的比值)分别为3.1、2.1,均以热带成分为主,热带性质突出;(2)在生活型谱上,以矮小型高位芽植物(35.53%)和一年生植物(25.75%)占比高,在叶性状方面以小型叶(67.66%)、纸质叶(45.51%)、单叶(85.03%)、非全缘叶(52.69%)、叶有被毛(54.49%)、落叶(67.66%)占据优势;果实以瘦果(19.76%)、微型果(83.23%)居多;传播方式以动物传播(44.91%)和风传播(31.14%)为主;(3)通过组平均聚类法将研究区植被划分为4类群系和10类群丛;(4)不同植物群落的物种多样性的大小顺序为台湾相思和木麻黄混交林>台湾相思林>黑松和台湾相思混交林>木麻黄林.各植物群落的草本层和灌木层的Simpson优势度指数、Patrick丰富度指数、Shannon-Wiener多样性指数均大于乔木层.(5)RDA排序表明,土壤全磷含量、土壤全钾含量、碱解氮、土壤pH值(P<0.05)是影响研究区植被多样性指数的主要环境因子,四者对植被多样性的总解释量为56.90%,仍存在43.10%未知环境因子及人为干扰等因素影响着植被多样性.本研究表明大练岛植物为适应强风干旱、辐射强、土壤贫瘠的恶劣环境,其功能性状表现出适应能力、繁殖能力与传播能力相应增强的特征;不同植被类型和群落不同层片的多样性指数存在差异,主要受土壤全磷、土壤全钾、碱解氮含量和土壤pH值的影响.(图2表7参52)

To determine the characteristics and ecological significance of a typical forest community of Dalian Island in Pingtan and provide a reference for the regeneration and succession,restoration and sustainable development of forest vegetation,in this study,field sampling was conducted to investigate the vegetation types,species composition,floristic characteristics,plant functional traits,and species diversity of the typical forest community.Redundancy analysis was used to analyze the correlation between species diversity and environmental factors.The results were as follows:(1)A total of 178 species of vascular plants belonging to 151 genera and 65 families were found in 18 quadrats.The R/T values of family and genera were 3.1 and 2.1 in seed plants,respectively,which were mainly composed of tropical elements with outstanding tropical properties.(2)Nano-phanerophytes(35.53%)and therophytes(25.75%)were prevalent among the vegetation.In terms of leaf characteristics,microphyll(67.66%),papery leaf(45.51%),simple leaf(85.03%),non-entire leaf(52.69%),pilous leaf(54.49%),and fallen leaf(67.66%)occupied the dominant position.The achene and mini fruit accounted for 19.76%and 83.23%of total plants on the island,respectively.The main dispersal mode of island plants tended to be zoochory(44.91%)and anemochory(31.14%).(3)Group average clustering was used to divide the vegetation in the study area,and it consisted of four formation types and ten association types.(4)The diversity of different plant communities was in following order of Form.Acacia confusa+Casuarina equisetifolia>Form.Acacia confusa>Form.Pinus thunbergii+Acacia confusa>Form.Casuarina equisetifolia.The Simpson dominance index,Patrick richness index,and Shannon-Wiener diversity index in the herb layer and shrub layer of each plant community were all higher than that of the tree layer.(5)The redundancy analysis ordination showed that total soil phosphorus,total soil potassium,alkaline hydrolyzable nitrogen,and soil pH value(P<0.05)were the main environmental factors affecting the diversity of forest communities in the study area.These factors explained were 56.90%of the variation,while the remaining 43.10%was due to unknown environmental factors and human interference factors affecting the diversity of forest communities.To adapt to the harsh environment caused by strong winds,drought,strong radiation,and poor soil quality on Dalian island,the functional traits of island plants showed the characteristics of enhanced adaptability,reproductive ability,and dispersal ability.The diversity indices for different vegetation types and communities in different layers were different,which was mainly affected by total soil phosphorus,total soil potassium,alkaline hydrolyzable nitrogen contents,and soil pH value.