海南岛霸王岭两种典型热带季雨林群落特征

热带季雨林为海南岛的隐域性植被类型,分布在与热带低地雨林相似的海拔范围但生境条件较差的局部地段,在旱季其大部分的乔木种类和个体都会落叶.海南岛霸王岭林区分布着海南岛最为典型且大都保存较为完好的热带季雨林原始林,按照其优势树种可划分为海南榄仁(Terminalia hainanensis)季雨林和枫香(Liquidambar formosana)季雨林两种群落类型.通过对霸王岭林区两种典型的热带季雨林老龄林群落的样地调查,比较分析了其物种组成、大小结构、多样性、季相变化等特征.结果表明:海南岛热带季雨林群落中物种优势度明显,具有明显的标志种--海南榄仁和枫香.海南榄仁群落具有较高的灌木物种丰富度、个体多度及较低的乔木物种丰富度、个体多度和多样性;海南榄仁群落在小径级和低高度级中具有较高的植物个体多度,同时在低高度级中具有较低的物种丰富度,但其它径级和高度级两个群落物种丰富度及个体多度差异均不显著;除灌木落叶物种丰富度海南榄仁群落显著高于枫香群落外,其余各生长型落叶物种丰富度及个体多度两个群落之间均无显著差异;在具刺木质藤本物种丰富度和个体多度上海南榄仁群落与枫香群落差异不显著,但乔木、灌木和木本植物具刺物种丰富度及个体多度海南榄仁群落均显著高于枫香群落.总体来看,海南榄仁群落比枫香群落的季雨林特征明显,是海南岛最为典型的季雨林群落类型.

Community features of two types of typical tropical monsoon forests in Bawangling Nature Reserve, Hainan Island

The tropical monsoon forest is an azonal vegetation type in Hainan Island and mainly distributes in the similar elevational ranges as the tropical lowland rainforest but in locations where environmental conditions are stressful, especially in the dry season. Most species and individual trees in the monsoon forest defoliate in the dry season. Bawangling Nature Reserve in Hainan Island contains well-preserved natural and typical tropical monsoon forests which can be classified into Terminalia hainanensis community type(TC) and Liquidambar formosana community type(LC) according to the dominant species. In this present study, species composition, structure, and diversity were investigated on three plots (50m×50m) for each of the two community types. On each plot, species name, height, and DBH(diameter at breast height) of all individuals≥1cm DBH were recorded. The community features of the two community types were compared and analyzed in terms of species richness, abundance, size class distribution, and deciduousness and presence of thorns. The results showed that only a few species (mainly T. hainanensis and L. formosana) apparently dominated in the tropical monsoon forests of Hainan Island. The species richness and abundance for shrubs were higher in the TC than in the LC whereas the species richness, abundance and Shannon-Wiener index for trees were lower in the TC than in the LC. The two community types had no significant difference in species richness and abundance for all but the smallest size class, in which the TC had greater plant density and lower species richness than the LC. The species richness and abundance for trees, shrubs and woody plants with thorns were higher in the TC than in the LC except for lianas, which showed no apparent difference between the two community types. Judging by the community features, the TC is more of typical tropical monsoon forest than the LC in Hainan Island.