Urbanization drives divergence in functional diversity and composition of woody plant communities in remnant forest patches

Urbanization has a profound impact on the ecological processes and plant diversity of remnant forests. To understand the relationship between urbanization and woody plant communities in remnant forests, we conducted a study in Guiyang, China, where we sampled 120 plots in 15 remnant forest patches along an urbanization gradient. We evaluated the functional diversity of woody plants based on four functional diversity indices and nine functional traits. We compared the functional diversity among different types of woody plants and between interior and edge communities, and analyzed the changes in functional diversity and individual functional traits along the urbanization gradient. Our results indicate that urbanization significantly decreases the functional diversity of woody plant communities. Additionally, urbanization leads to shifts in functional composition, particularly in shrub species, with an increase in leaf N content and a decrease in leaf C content, leaf C/N ratio, seed germination rate and seed mass. These findings suggest that increasing urbanization reduces the values of high resource-conserving traits of woody plants in remnant forests. Therefore, it is crucial to limit additional urban expansion around remnant forest patches to protect the functional diversity and crucial plant species with strong resource-conserving traits.