宁德三都澳海岛马尾松林群落特征及物种多样性

海岛人工林建设有利于减弱和消除海岛生态脆弱性,但目前单一的人工林群落结构存在较多的缺点,选用的植被也存在不适应海岛环境的问题。通过样方法对宁德三都澳6个海岛的马尾松(Pinus massoniana)半自然林的植被类型、物种组成、植物功能性状、物种多样性进行分析,并利用冗余分析法分析物种多样性与环境因子的相关性,旨在了解其演替状况,群落结构特征和物种组成,及其物种多样性与环境因子的相关关系,丰富当地植被基础资料,同时为海岛人工林建设、植被修复选择及当地马尾松林的合理经营和管理提供理论基础。结果表明:(1) 40个样方共记录维管束植物86科168属255种(含5变种),在生活型谱上,以乔木(37.25%)和灌木(30.20%)植物种类最多,高位芽植物(83.92%)占比显著,对光耐受性以中性植物(69.02%)为主。(2) 通过组平均聚类法将研究区植被划分为5类群系33类群丛,分属于常绿针阔混交林和常绿针叶林2种植被型。(3) 常绿针阔混交林的多样性指数显著(P<0.05)高于常绿针叶林,但受林分郁闭度的影响,马尾松+杨桐(Adinandra millettii)林灌木层多样性指数明显偏低。(4) 灌木层是马尾松林中的绝对优势层片,多样性指数(除Pielou指数外)均显著(P<0.05)高于乔木层和草本层。草本层受芒萁化感作用的影响,多样性指数明显偏低。(5) 冗余分析法(RDA)分析结果表明,土壤pH和速效钾显著(P<0.05)影响群落的物种多样性指数,两者对物种多样性的总解释量为27.6%。(6) 灌木层鹅掌柴重要值与群落郁闭度之间存在显著(P<0.05)的二次函数关系。

Characteristics of Pinus massoniana forest community and species diversity of island in Sandu Gulf, Ningde, Fujian Province

The construction of plantantion forest in island is conducive to weakening and eliminating the ecological vulnerability of the island. However, there are many shortcomings in the currently single plantation forest community structure, and the selected vegetation also has the problem of not adapting to the island environment. In this study, the vegetation types, species composition, plant functional traits, and species diversity of Pinus massoniana semi-natural forests in six islands of Sandu Gulf of Ningde were analyzed by sample method, and the correlation between species diversity and environmental factors was analyzed by redundancy analysis(RDA). The aim is to understand the succession status, community structure characteristics, species composition, and the correlation between species diversity and environmental factors, enrich the basic data of local vegetation, and provide a theoretical basis for the construction of island plantation, vegetation restoration selection, and rational management of local Pinus massoniana forests. The results showed that: (1) a total of 255 species (including 5 varieties) of vascular plants belonging to 168 genera and 86 families were recorded in 40 quadrats. In the life form spectrum, arbor and shrub species were the most, accounting for 37.25% and 30.20% of the total number of species, respectively. Phanerophytes accounted for a significant proportion, accounting for 83.92%. The light tolerance of neutral plants was dominant, accounting for 69.02%. (2) The vegetation in the study area was divided into 5 groups and 33 associations by group average clustering method, which belonged to 2 vegetation types of evergreen coniferous and broad-leaved mixed forest and evergreen coniferous forest. (3) The diversity index of evergreen coniferous and broad-leaved mixed forest was significantly (P<0.05) higher than that of evergreen coniferous forest, but the diversity index of shrub layer in Pinus massoniana +Adinandra millettii forest was significantly lower due to the influence of canopy density. (4) Shrub layer was the dominant layer in Pinus massoniana forest, and the diversity index (except Pielou index) was significantly (P<0.05) higher than that of arbor layer and herb layer. The herbaceous layer was affected by allelopathy of Dicranopteris pedata, and the diversity index was obviously lower. (5) The results of redundancy analysis showed that soil pH and available potassium significantly (P<0.05) affected the species diversity index of the community. The two soil factors accounted for 27.6% of the species diversity, but there were 72.4% unknown factors. (6) There was a significant (P<0.05) quadratic function relationship between the importance value of Schefflera octophylla in shrub layer and crown density.