The Impact of Urbanization on Avian Communities During the Breeding Season in the Huanghuai Plain of China

The noise pollution, habitat loss, and human disturbance caused by urbanization have damaged bird communities. Research on the relationship between urbanization and birds has predominantly focused on highly urbanized areas, with relatively few studies in underdeveloped urbanized areas. Here, we conducted bird surveys along the urban-rural continuum by utilizing 150 line transects within a 51,385 km² area from June to August in 2022 and 2023, aiming to explore the impact of urbanization on bird species diversity and functional traits during the breeding season in the Huanghuai Plain of China. We found significant differences in species diversity and functional traits among three habitats along the urban-rural continuum (i.e., urban, suburban, and rural). Additionally, a measure combining several aspects of urbanization (the urban synthetic index) had significant negative correlations with species richness and the Shannon-Wiener index, while it had no significant correlation with functional traits. We then assessed that the environmental noise, the distance to the county center, and the proportion of building area within a 250-m radius were critical factors affecting species diversity, as well as environmental noise and the distance to the county center were the best predictors for functional traits. The composition and proportions of diets and nest types of birds were similar across the urban, suburban, and rural habitats. Our study highlights the importance of environmental noise, the distance to the county center, and the building index in protecting urban birds in the Huanghuai Plain. The research findings filled a gap in the study area regarding the relationship between urbanization and avian communities based on the urban-rural continuum.