Resource phenology and transient dynamics shape urban avian guild stability: A modeling framework for urban green planning

Urban ecosystems exhibit pronounced temporal and spatial variability, yet the mechanisms by which resource pulses and habitat heterogeneity shape avian community stability remain poorly understood. Using generalized linear mixed models and sensitivity analyses, we examined how fruit and nectar availability influence the transient dynamics of frugivore and nectarivore guilds across urban sites in northern Taiwan. Resource pulses during peak fruiting periods significantly enhanced frugivore stability, while nectarivores remained unstable due to spatiotemporally ephemeral floral resources. Spatial heterogeneity further modulated these effects: fragmented habitats limited fruit availability, thereby necessitating a dietary shift toward animal prey, which was associated with amplified community volatility. Our framework integrates diet composition, phenological timing, and “structural stability” to model non-equilibrium dynamics under urban change. These findings underscore the need for dynamic biodiversity models that account for transient responses to resource and habitat fluctuations, informing adaptive urban conservation strategies.