The Relationship Between Macroinvertebrate Diversity Indices and Community Stability in the North Canal River Basin of Urban Beijing, China

Understanding the contribution of macroinvertebrate diversity indices to community stability in urban rivers is critical for developing more effective strategies to manage and conserve the ecological health of urban rivers and to maintain sustainable regional economic and social development. However, knowledge regarding the relationship between environmental factors, multidimensional biodiversity, and community stability in urban rivers remains limited. In this study, we investigated the relationships among macroinvertebrate multidimensional diversity, secondary productivity-to-biomass ratio (SP/B), and average variation degree (AVD) in a typical urban river—the North Canal River basin in Beijing—to identify which biodiversity metric best indicates community stability. Macroinvertebrates were extensively sampled from September to October 2020 in the North Canal River basin (BYH), a typical urban river in Beijing. We comparatively analyzed the spatial variation in different types of diversity—species diversity (SD), functional diversity (FD), and phylogenetic diversity (PD)—as well as SP/B and AVD between the upstream and midstream–downstream reaches of the river under varying degrees of urbanization and human disturbance. Partial Least Squares Structural Equation Modeling (PLS-SEM) was used to assess the relationships among multidimensional diversity, SP/B, and AVD. The results showed that upstream environmental factors and diversity indices together explained 52.9% and 52.0% of the variance in SP/B and AVD, respectively, while midstream–downstream factors explained 65.9% and 84.2%, respectively. These findings suggest that both SP/B and AVD are suitable indicators for examining the relationships between macroinvertebrate community stability, diversity indices, and environmental factors in the BYH. In the upstream region, total phosphorus (TP), FD, and PD were more indicative of SP/B in the central urban area, while SD and PD were more indicative of AVD. In contrast, in the midstream–downstream suburban areas, dissolved oxygen (DO), SD, and PD were more indicative of SP/B, while FD and PD were more indicative of AVD. These findings demonstrate that PD is a stronger indicator of both SP/B and AVD under varying anthropogenic disturbances and environmental conditions. The PLS-SEM results also indicated differences in the specific effects of FD and SD on community stability across the upstream and midstream–downstream sections, as well as differences in the direct effects of environmental factors such as TP and DO. These results suggest that PD is more sensitive than FD and SD in detecting the impacts of anthropogenic disturbances and environmental fluctuations on macroinvertebrate community stability in urban rivers. Our study provides evidence that PD outperforms FD and SD in predicting macroinvertebrate community stability in urban river ecosystems and that the combined use of SP/B and AVD better reveals the complex interactions between biodiversity and environmental factors influencing community stability. This combination can thus enhance our understanding of how biodiversity affects macroinvertebrate community stability in urban rivers.