Hydrogeomorphic conditions drive aquatic macroinvertebrate diversity between depression and slope wetlands in a mountainous region

Aquatic macroinvertebrates inhabiting freshwater wetlands make important contributions to biodiversity. However, environmental characteristics of wetlands is often varied in a specific region, especially in mountainous areas. We investigated 24 depression wetlands and 20 slope wetlands in the Great Xing'an Mountains in Northeast China and aimed to reveal the hydrogeomorphic settings in driving the wetland aquatic macroinvertebrate diversity and offer insights to environmental management. We found that depression wetlands supported higher taxonomic richness and more habitat specialists. Fifteen orders or infraclasses responded positively to depression wetlands, whereas eight orders responded positively to slope wetlands. The composition of aquatic macroinvertebrate assemblages differed significantly between the depression and slope wetlands. Additionally, the variation in species composition in the depression and slope wetlands are largely explained by habitat variables. For community assembly of aquatic macroinvertebrates, both wetland types were largely driven by stochastic processes, with a higher proportion observed in the slope wetlands. Whereas a significant distance-decay relationship and stronger dispersal limitation were detected in the depression wetlands. These findings enhance our understanding of diversity patterns and mechanisms driving aquatic macroinvertebrate community assembly in mountain wetlands. Our research also highlighted the critical need to attach importance to hydrogeomorphic settings and habitat variables in driving aquatic macroinvertebrate diversity for more effective wetland management and conservation.