Abstract:
Both habitat filtering and dispersal limitation are the key ecological processes affecting the structuring
of community diversity pattern. The spatial scales at which different ecological processes work were
determined in the structuring of species diversity pattern. The effect of 40 woody species on the local
species richness was examined by individual species-area relationship model. The significance of
deviation of individual species-area relationship from neutral condition was analyzed by homogeneous
Poisson process, heterogeneous Poisson process, homogeneous Thomas process and heterogeneous Thomas
process. The results revealed that Corylus mandshurica, Rhamnus davurica, Lonicera praeflorens, Acer
ginnala and Fraxinus rhynchophylla were diversity accumulators at 0-50 m spatial scales. Tilia
mandshurica at 0-25 m scale and Carpinus cordata at 0-35 m scale were diversity repellers, while most of
other species were neutrals. The dispersal limitation greatly affected the structuring of community diversity
pattern; however, the effect of habitat filtering was relative small. Heterogeneous Thomas model could
simultaneously exclude the effects of habitat filtering and dispersal limitation. The results indicated that
diversity accumulators were dominant at 0-20 m spatial scales in forest community. The proportion of
diversity neutrals at scale 20 m increased with the increasing spatial scales, and the diversity neutrals
dominated the structuring of the community diversity. Diversity repellers kept in a very low proportion at
all scales. Thus, the niche differentiation and neutral processes jointly determined the structuring
processes of community diversity, and the relative importance of both was closely correlated with the
spatial scales.