Changes in plant functional traits and their relationships with environmental factors along an urban-rural gradient in Guangzhou, China

Rapid urbanization in southern China has had significant impacts on the monsoon evergreen broad-leaved forests and caused a series of environmental issues. How plants, in particular plant functional traits, respond to urbanization is hence of importance for their acclimation to changing environments. In this study, we investigated the changes of plant functional traits associated with plant competition and nutrient utilization strategies and their relationships with environmental factors along an urban-rural gradient in Guangzhou, China. Results showed that plant species in the urban forests had larger specific leaf area (SLA), higher leaf nitrogen (LN) content, and lower leaf carbon/nitrogen ratio (C:N) than those in the suburban and rural forests. Principal component analysis revealed that species in the urban, suburban, and rural forests were significantly separated by the first principal component, which was strongly related to SLA and leaf nutrient traits. Plant functional traits were also found closely related to soil pH, nitrogen, and copper content. Species with higher SLA and higher LN content were better adapted to the urbanization environment. Our findings indicate that the process of urbanization may change the composition of lower subtropical monsoon evergreen broad-leaved forests by favoring acquisitive-strategy species, and further influence ecosystem services.