Disentangling Environmental Effects on the Tree Species Abundance Distribution and Richness in a Subtropical Forest.

摘要: As a transitional vegetation type between evergreen broadleaved forest and deciduous forest, evergreen-deciduous mixed is composed of diverse plant species. This distinctive generally distributed in mountainous areas with complex landforms heterogeneous microenvironments. However, little known about the roles environmental conditions driving species diversity patterns this forest. Here, based on 15-ha plot central China, we aimed to understand how what extent topographical characteristics soil nutrients regulate number relative abundance tree We measured factors (terrain convexity, slope, total nitrogen, phosphorus concentrations) (species distribution richness) 20 m × subplots. Species was characterized by skewness, Berger-Parker index, proportion singletons. The generalized additive model used examine variations caused factors. structural equation assess whether via nutrients. found that had significant negative effects richness positive all metrics distribution. Convexity distribution, but these were mostly mediated Slope skewness almost independent Soil together accounted for 9.5-17.1% and, respectively, 8.9-13.9% 3.3-10.7% variations. concluded more important than regulating diversity. Increased nutrient concentration led decreased taxonomic increased dominance rarity. could be better proxy slope. Moreover, abiotic played limited patterns, it possible observed are also driven some biotic not considered here.