Urbanization facilitates colonization and reshapes strangler-host networks: the fate of strangler figs in a tropical urban landscape and implications for management

Mo, Yu-Xuan

URBAN FORESTRY & URBAN GREENING

2026

124

Song, L

Urbanization acts as a powerful ecological filter that profoundly reconfigures species interactions. This study examines its impact on the complex association between strangler figs and their host trees in a tropical region of Southwest China. Through an investigation of over 50,000 trees and a comparative analysis across an urban area and a nearby protected rainforest, we quantified changes in diversity, abundance, and the ecological network of strangler figs and their hosts. Our results revealed that compared with the rainforest, strangler fig colonization in the urban area was six times higher. However, their progression to later, host-threatening stages was significantly limited. Urbanization also led to a marked shift in species composition and a simplification of host tree diversity. Notably, the specialized and modular strangler-host network with diverse species in the rainforest was transformed into a more generalized and nested network in the urban area, dominated by a few generalist strangler fig species on introduced hosts, particularly the oil palm (Elaeis guineensis). These findings illustrate that urbanization simplifies the participant species pool yet simultaneously complicates the structure of their ecological networks. For urban forestry practice, this study highlights that targeted management and monitoring of susceptible host trees can help balance the biodiversity value of strangler figs with the health of urban trees, providing critical insights for sustainable greening in tropical cities.