Abstract:Based on a long term survey of plant population dynamics, we investigated 26 gaps to study the factors that affect sapling species composition and biodiversity in gaps at different succession stages in Dinghushan Biosphere Reserve. Gap formation, gap size and age, topography and location, adult tree around gaps, saplings of tree species growing in the gaps were investigated. The formation of gaps resulted from landslide, storm, pest damage, etc. Sapling composition, sapling density and diversity in gaps were different due to different causes of gap formation. Species growing in the gaps were quite different because of their differences in shade tolerance and in succession stages. Differentiation of regeneration niche was caused by variation of gap size, age and topographic factor, which resulted in the appearance of sapling guild in the gaps.