海南岛热带低地雨林木本植物幼苗层组成与功能群恢复动态

以海南岛霸王岭林区内不同恢复阶段低地雨林幼苗(DBH<1 cm)层为研究对象,比较了不同恢复群落中幼苗的物种组成和功能群变化,分析了幼苗层的自然恢复动态。结果表明:不同恢复阶段幼苗层的物种组成存在显著差异;不同恢复阶段幼苗层的物种个体多度都随高度级的增加而减少,其中,第I高度级幼苗的物种数和个体多度在各个恢复时期均显著高于其它3个高度级,这说明幼苗层的存活曲线接近凹型;恢复60年的次生林群落中幼苗的个体多度最高,符合中度干扰假说;随着恢复时间的增加,不同功能群重要值表现出明显的变化规律,先锋种的重要值随恢复时间的增加逐渐减少,而耐荫种的重要值则随恢复时间的增加而逐渐增大,说明在恢复过程中耐荫种逐渐取代先锋种,从而实现了群落的更新和演替。

Recovery Dynamics of Seedling Composition and Functional Groups in the Tropical Lowland Rain Forest on Hainan Island, China

The seedling layers(DBH<1 cm)under different recovery stages in the tropical lowland rain forest on Hainan Island were selected as study object. The species composition and variation of functional group of seedling community in different recovery phases were surveyed. The results showed that there were different species compositions of seedling community in different recovery stages. The seedling abundance decreased with the increase of height classes. The seedlings in the lowest height class had higher abundance than those in the other height classes These indicated that the survival curve of seedlings was close to the concave curve. The seedling abundance peaked in the 60-years-old secondary forest, which compiled with the intermediate disturbance hypothesis. Importance values of different functional groups varied significantly with recovery. The pioneer species decreased while the climax species increased with the increase of recovery time.