Cd contamination determined assembly processes and network stability of AM fungal communities in an urban green space ecosystem

The effects of cadmium (Cd) contamination on the assembly mechanism and co-occurrence patterns of arbuscular mycorrhizal (AM) fungal communities remain unclear, especially in urban green spaces. This study sequenced AM fungal communities in greenbelt soils in Zhengzhou (China). The effects of Cd contamination on the AM fungal diversity, community assembly processes, and co-occurrence patterns were explored. We found that (1) an increase in Cd contamination changed the community composition, which resulted in a significant improvement in the diversity of specialists of AM fungi and a significant decrease in the diversity of generalists. (2) Deterministic processes dominated the community assembly of specialists and stochastic processes dominated the community assembly of generalists. (3) Specialists played a more important role than generalists in maintaining the stability of AM fungal networks under Cd contamination. Overall, Cd contamination affected the ecological processes of AM fungi in urban green space ecosystems. However, the effects on the assembly processes and network stability of different AM fungi taxa (specialists and generalists) differed significantly. The present study provides deeper insight into the effect of Cd contamination on the ecological processes of AMF and is helpful in further exploring the ecological risk of Cd contamination in urban green spaces.