摘要 : This study examined the spatial distribution of seeds in the soil seed banks of a tropical semi-deciduous forest and adjacent grassland at Wasgomuwa National Park, Sri Lanka and some factors responsible for the spatial heterogenei... 展开 This study examined the spatial distribution of seeds in the soil seed banks of a tropical semi-deciduous forest and adjacent grassland at Wasgomuwa National Park, Sri Lanka and some factors responsible for the spatial heterogeneity. It also evaluated how soil seed banks would contribute to forest regeneration or degeneration. Two soil seed bank types were identified in the study area: those of the forest and the grassland. In between these two, there was a narrow transitional zone, a forest-grassland ecotone, which contained large numbers of seeds of grassland species and seeds of some forest pioneer and agricultural weed species. These soil seed banks are highly heterogeneous, and clumping of seeds occurred frequently. Composition of the local vegetation, fruiting season and the seed dispersal patterns greatly affected this heterogeneity. Seeds of woody forest species were hardly found in the grassland implying that invasion of forest into grasslands would not occur spontaneously. Seeds of grassland species were frequently dispersed into the forest interior mainly by herbivores. If the forest or the forest edge gets disturbed, these seeds would germinate and establish, and this would result in the reduction of the forest cover and, subsequently, expansion of the grassland.. 收起