Effects of the topographic niche differentiation on the coexistence of major and minor species in a species-rich temperate forest

摘要

Topographic niche differentiation (TND) is believed to facilitate the coexistence of tree species, but its effects are not well established for minor species or for life stages beyond recruitment. In this study, the ef-fects of topography (slope inclination and topographic configuration) on the demographic parameters (mortal-ity, diameter growth rate and recruitment rate) of both major and minor species in a species-rich temperate forest were examined using a mixed-model approach. The model selection analysis detected interspecies dif-ference in the response of recruitment rate to topo-graphic configuration. However, mortality and diameter growth rate of stems with DBH > 5 cm did not show any species-specific response to two topographic parameters. The recruitment rate of major species ten-ded to be higher under topographic conditions where many stems of the species already existed, suggesting significant habitat segregation. No such correlation was found for minor species. These results suggest TND has a limited effect on habitat segregation among species, and that other mechanisms also contributed to coexis-tence, especially when considering minor species.