西双版纳勐腊望天树热带季节雨林蕨类植物组成及生态特征

Floristic composition and ecological characteristics of ferns in a tropical dipterocarp rainforest in Mengla, Xishuangbanna

关键词:  云南勐腊  望天树林  蕨类组成  生态特征

Key words:  Mengla of Yunnan  fern forest  floristic composition  ecological characteristics

摘要:

采用生态学样方调查及统计学方法,研究了云南勐腊望天树热带季节性雨林蕨类植物的组成及生态特征。结果表明:在1 hm²(4个50 m×50 m,含400个5 m×5 m小样方)面积的样地里,记录有蕨类植物48种13 159株(丛); 在生态特征上,40个地生蕨类的盖度之和占调查样地面积的22.45%,缺乏高盖度级种类; 黑鳞轴脉蕨、长叶实蕨、多形叉蕨等属高频度级种类; 长叶实蕨、多形叉蕨、黑鳞轴脉蕨、毛柄短肠蕨、薄叶牙蕨、思茅叉蕨等种的重要值之和占86.31%,它们是望天树林蕨类植物的典型代表种。生活型组成上,以地面芽植物占优势(达80%)。叶质主要由纸质叶(占54.17%)和草质叶(占27.08%)种类组成; 叶形主要由羽状复叶种类组成(89.58%)。与西双版纳相同取样面积的山地常绿阔叶林比较,望天树林蕨类植物的种数及种群数量分别是山地常绿阔叶林的1.55倍及2.23倍。同一地区不同海拔和生境异质性是导致蕨类植物组成不同、种群数量变化的主要原因。该研究揭示了赤道热带北缘热带雨林蕨类植物的组成及生态特征,有利于与其它热带地区蕨类植物作进一步的比较研究。

Abstract:

Based on ecological plot surrey and statistical analysis,the species composition and ecological characteristics of the ferns in the dipterocarp rain forest in Mengla,southern Yunnan were studied. In a 1 hm² sampling plot(4 subplots of 50 m×50 m,with 400 small quadrats of 5 m×5 m),48 species with 13 159 individuals were recorded. In ecological characteristics,40 species of non epiphytical ferns had 22.45% coverage of the plot area,but lack of species with high coverage. Tectaria fuscipes,Bolbitis heteroclita,Tectaria polymorpha had high frequency distributions,and Bolbitis heteroclita,Tectaria polymorpha,T. fuscipes,Diplazium dilatum,Pteridrys cnemidaria,Tectaria herpetocoulos contributed 86.31% of important values in the plot. They were the representatives of the ferns in the dipterocarp forest. In life forms,hemicryptophytes contributed 80% of the total species. The species with chartaceous leaves made up 54.17% of the total species,and herbaceous leaves made up 27.08%. In leaf types,the species with pinnate leaves contributed to 89.58% of the total species. Compared to the tropical montane evergreen broad-leaved forest with 1 hm² sampling area in Xishuangbanna,the number and dominance of fern species in the dipterocarp rain forest were conspicuously more. The different altitude and habitats were the main factors to species composition and their populations. The results could be helpful to make comparison with other tropical forests.