海南鹦哥岭热带山地雨林不同海拔植物群落结构与相似性分析

Structure and Similarity Analysis of Plant Communities at Different Altitudes in the Tropical Mountain Rainforest of Yinggeling, Hainan Province

热带山地雨林是热带雨林中重要的森林植被类型之一,是维持区域生态安全和保护生物多样的重要保障。为研究海拔和坡向对热带山地雨林群落结构与相似性的影响,选取鹦哥岭自然保护区南、北坡向不同海拔的热带山地雨林内设置的8个50 × 50 m的固定样方,对比研究不同海拔和坡向乔木植物群落的优势种组成、物种多样性及相似性。结果表明:样地植物群落物种丰富,共61科146属246种,壳斗科、山茶科、大戟科和樟科为主要优势科,各样地优势科、属、种的海拔梯度变化具有异质性。样地植被物种丰富度和物种多样性随海拔的升高呈现先升高后降低的变化规律,分别符合“中峰分布”格局和“中间高度膨胀”学说。不同坡向对应海拔的植物群落多样性存在差异,主要受水热、地形等复杂多变的环境因子影响。不同海拔样地间的植物群落结构差异大,群落相似性为极不相似水平。海拔梯度影响植物群落科、属的分布型;科的泛热带分布占绝对优势,属的泛热带、热带亚洲和北温带分布比例较高。因此,对热带山地雨林开展长期的森林动态监测,将有助于深入了解该类型雨林的群落构建规律以及物种多样性维持机制。

Tropical mountain rain forest is one of the most important forest vegetation types in tropical rain regions. It can provide an important foundation to maintain regional ecological security and con-serve biodiversity. In order to study the effects of altitude and aspect on community structure and similarity of tropical mountain rain forests, eight fixed sample squares of 50 × 50 m were selected form the south and north slopes of Yinggeling Nature Reserve, which were set up in tropical moun-tain rain forest at different altitudes. The dominant species composition, species diversity and sim-ilarity of tree plant communities on northern and southern slopes were compared. The results showed that the plant community in the plot was rich in species, with a total of 246 species,146 genera and 61 families. Fagaceae, Camellia, Euphorbiaceae and Lauraceae were the main dominant families. The elevation gradients of dominant families, genera and species in each plot were heter-ogeneous. The vegetation species richness and species diversity of the sample plot increased first and then decreased with the increase of altitude, which conformed to the pattern of “Middle Peak Distribution” and the theory of “Middle Height Expansion”, respectively. The diversity of plant communities on different slopes at the same altitude was mainly influenced by complex and changeable environmental factors such as water, heat and topography. The altitudinal gradient af-fects the distribution patterns of families and genera, the structure of plant community was differ-ent in different altitude plots, and the similarity of plant community was very different. The pan-tropic distribution of families was dominant, and the pan-tropic, tropical Asia and north tem-perate distribution of genera were relatively high. Therefore, long-term monitoring of forest dy-namics in the tropical mountain rain forest will promote a deeper understanding of the community formation and species diversity maintenance mechanism of this type of rain forests.