摘要 : The nature and the magnitude of the soil seed bank of tropical semi-deciduous forests at Sigiriya, Sri Lanka were examined in 41 experimental plots established along a chronosequence of forest age to reveal the potential role of t... 展开 The nature and the magnitude of the soil seed bank of tropical semi-deciduous forests at Sigiriya, Sri Lanka were examined in 41 experimental plots established along a chronosequence of forest age to reveal the potential role of the soil seed banks in forest regeneration and succession following a large-scale disturbance. Species composition and abundance in the soil seed banks were influenced by the time of the year and the structure of forests where the latter is highly determined by the age of forests after a large-scale disturbance. Clumping of seeds in the soil seed bank was commonly seen in all studied forests. Soil seed banks of young successional forests were dominated by agricultural weeds, and their seeds were mainly dispersed by wind. Therefore, such seed banks do not often contribute to the forest regeneration. After about 20 years, the diversity of the soil seed bank increased and the seed banks contained some forest tree and shrub seeds. Since the microclimate of such forests are more favourable for seed germination and seedling establishment, seeds which reach these forests might germinate and establish well, contributing to successful forest regeneration and succession. Seed banks of mature forests contain fewer seeds but are also dominated with grass and agricultural weed species. Therefore, these seed banks cannot support the natural regeneration of tropical semi-deciduous forests after a large-scale disturbance. Instead, seeds of grass and agricultural weed species would germinate and establish if a disturbance occurs. Therefore, such forests are under a threat of degeneration with frequent disturbances.. 收起