Habitat-mediated reassembly of rodent assemblages along an urban–suburban–rural gradient

Abstract Urbanization profoundly alters habitats and biological communities; however, its impacts on rodent assemblages and functional traits across varying habitat types remain inadequately understood. We surveyed rodents across 81 subplots encompassing woodland, farmland, and residential habitats along an urban-suburban-rural gradient in Wuhan, a rapidly urbanizing megacity of central China. We collected data on species composition, external morphology, organ traits, and local environmental covariates, analyzing them via multispecies count models, beta-diversity partitioning, community-weighted mean trait decomposition, ordination, path analysis, and nested cross-validation. In 9,720 trap-nights, we captured 246 individuals representing six species across four genera. Capture success increased from urban to rural sites and was significantly higher in farmland and woodland than in residential areas. Rodent assemblage composition varied significantly with urbanization, habitat type, and their interaction, with habitat explaining a substantially greater proportion of the variation. Residential assemblages were characterized by larger body-sized Rattus spp., whereas farmland and woodland were dominated by the smaller Apodemus agrarius and Niviventer confucianus , respectively. Among-site variation in community-level body size was primarily driven by species turnover and shifts in dominance, whereas organ traits exhibited high intraspecific heterogeneity that was not consistently explained by the measured environmental variables. Furthermore, human activity intensity was significantly associated with assemblage composition. These findings suggest that urbanization shapes rodent functional composition predominantly through habitat-mediated species turnover and dominance shifts, rather than through uniform intraspecific responses. This study underscores the necessity of habitat-specific rodent monitoring and management strategies in rapidly urbanizing landscapes.