Differential Impacts of Anthropogenic Disturbance on Community Composition and Alpha Diversity of Macroinvertebrates at a Large Urban River System

ABSTRACT

Macroinvertebrates play critical roles in aquatic ecosystems, yet the effects of anthropogenic land‐use disturbance on macroinvertebrate communities and their taxonomic and functional diversity remain poorly understood, particularly in rapidly urbanizing regions of eastern China. Here, we identified 211 macroinvertibrates species from 385 river sites in Ningbo, Zhejiang Province, China. We classified sites as low‐disturbance (LD) or high‐disturbance (HD) based on surrounding land use. This study examined differences in macroinvertebrate community composition, taxonomic and functional diversity, and functional feeding groups (FFGs) between disturbance levels, and further explored the potential direct and indirect effects of land use and environmental factors using structural equation modeling (SEM). Macroinvertebrate community composition differed significantly ( p  = 0.001) between LD and HD sites, with HD sites showing lower taxonomic and functional diversity. The relative abundance of FFGs also shifted with disturbance level, with filterers, gatherers, and predators more abundant at LD sites, whereas scrapers and shredders increased at HD sites. SEM further indicated that agricultural and urban land uses were negatively associated with both taxonomic and functional diversity, while non‐purgeable organic carbon (NPOC) showed a positive association with diversity. These findings demonstrate that anthropogenic land‐use disturbance can restructure macroinvertebrate communities and reduce multiple dimensions of biodiversity, highlighting the importance of integrating both taxonomic and functional information into ecological assessments of human‐dominated river systems.