Global Change Alters the Abundance and Community Structure of Arbuscular Mycorrhizal Fungi and Influences Plant Mycorrhizal Benefit

ABSTRACT Aims Arbuscular mycorrhizal (AM) fungi play critical roles in ecosystem services and exhibit sensitivity to global change factors (GCFs). However, the interactive effects of multiple GCFs on AM fungal communities, and whether changes in AM fungal communities have a feedback effect on plant–mycorrhizal benefits under global change remain poorly understood. Location Global. Time Period 1990 – 2022. Major Taxa Studied Arbuscular mycorrhizal fungi; arbuscular mycorrhizal plant hosts. Methods We synthesised 1646 observations of arbuscular mycorrhizal (AM) fungal communities from field experiments to evaluate how manipulated GCFs affect their abundance and community structure and to determine the potential consequences for outcomes of plant–mycorrhizal fungal relationships. Results The interactive effects among GCFs were mainly additive rather than synergistic or antagonistic. AM fungal diversity was not consistently sensitive to the individual effects of GCFs; however, a significant shift in community structure occurred under individual or concurrent GCFs. When multiple factors were imposed simultaneously, their negative effect on AM fungal colonisation was strengthened, while their effects on community structure were diminished. Moreover, plant performance was closely linked to changes in abundance and community structure of AM fungi under GCFs. Experimental duration and environmental variables emerged as the most important predictors of AM fungal responses to GCFs. Conclusions Reordering or replacement of AM fungal species has been identified as the key mechanism driving community responses to GCFs. Our study highlights the need to monitor AM fungal community structure and associated functional consequences for plant communities under ongoing global change.