Abstract:The growth, survival, reproduction, and spread of plants are significantly influenced by functional traits. Understanding the distribution pattern of plant functional traits is helpful to reveal the process of community construction and its internal mechanism. Twelve different functional traits of woody plants in Dinghu Mountain subtropical mountain evergreen broad-leaved forest and gully rainforest were collected and measured. The quadrats of 5 m×5 m, 10 m×10 m and 20 m×20 m were used as scale units, respectively. The distribution pattern and driving mechanism of functional traits in communities were investigated by calculating mean pairwise trait distance (PW). The results showed that the 12 functional traits of the two forest types had different degrees of variation, but there was no significant difference between the communities (P>0.05). The spatial distribution pattern of functional traits in the two forest types was scale dependent, but the driving mechanism was different at different scales. With the increase of spatial scale, the main driving mechanism of spatial distribution pattern of functional traits in the mountain evergreen broad-leaved forest changed from environmental filtering to diffusion restriction. The environmental filtering and similarity restriction of ravine rainforest were changed to diffusion restriction, and both forest types were diffusion restriction at the spatial scale of 20 m×20 m. Niche differentiation and dispersal restriction were involved in the formation of community functional traits distribution pattern and community construction in the subtropical mountain evergreen broad-leaved forest and gully rainforest in Dinghu Mountain, and the contribution of both changes with spatial scale. Slope is the most important topographic factor affecting the distribution pattern of functional traits in mountain evergreen broad-leaved forest, and elevation is the most important topographic factor affecting gully rainforest.