Contrasting Responses of Rodents With Different Habitat Associations to Rapid Urbanization in a Chinese Megacity

Urbanization is critical in reshaping wildlife, yet multi-level responses of animals remain poorly understood. Here, to test whether rodents with different habitat associations exhibit divergent responses to rapid urbanization, we selected three representative species: the brown rat (Rattus norvegicus), a synanthropic species; the striped field mouse (Apodemus agrarius), a farmland-associated species; and the Chinese white-bellied rat (Niviventer confucianus), a woodland-associated species. We investigated their population size, morphological traits, and gut microbiota along the urban-rural gradient in the Wuhan metropolitan area, central China. The results showed that population size increased in R. norvegicus but decreased in A. agrarius and N. confucianus with increasing urbanization. Ear length and tail length of R. norvegicus were shorter in more urbanized areas, while the other morphological traits showed no consistent trends across species. Gut microbiota diversity exhibited pronounced species-specific patterns, whereby microbial richness increased but community heterogeneity decreased in R. norvegicus, and richness declined but community heterogeneity increased in A. agrarius, whereas those of N. confucianus showed no great changes with increasing urbanization. Predicted functional profiles of gut microbiota differed among species, primarily associated with environmental adaptation, antimicrobial resistance, immune regulation, and metabolic processes. The results indicate that rodent responses to rapid urbanization are different, in which urban exploiters (e.g., R. norvegicus) showed greater plasticity and resilience, while urban avoiders (e.g., N. confucianus) would suffer from more severe negative impacts. These results are beneficial for understanding the ecological consequences of rapid urbanization and improving conservation of urban wildlife.