Shifts in plant ecological strategies in remnant forest patches along urbanization gradients

Abstract

Urban remnant forests are biodiversity hotspots in cities, and a better understanding of the plant response in remnant forests to urbanization can promote biodiversity conservation. To explore the relationships between plant ecological strategies in remnant forests and urbanization, we used Guiyang, China, as the study case location and measured the seed mass, maximum height and specific leaf area of woody plant species in 72 survey plots in nine remnant forest patches. We positioned the woody plant species in the eight quadrants of a three-dimensional plot based on the three functional traits presented above and explored their ecological strategies. The abundance of each trait group was calculated in the edge and interior habitats under different levels of urbanization (the percentage of impervious surfaces <20 %, 20 %–50 %, >50 %), and differences were examined. We found that high levels of urbanization decreased tree species with the ecological strategies of slow growth, high resource conservation, strong survivability and high competitiveness but increased the abundance of shrub species with the traits of long-distance dispersal, widespread distribution and competitiveness. These results suggest that the high intensity of human interference threatens the preservation of postsuccessional plant species with resource conservation traits. Urbanization drove the shifts in plant strategies to adapt to disturbances and habitat fragmentation. We recommend that further urban expansion surrounding remnant forest patches should be controlled to protect postsuccessional species.