Global change alters the abundance and community structure of arbuscular mycorrhizal fungi and influences plant mycorrhizal benefit

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 have a feedback effect on plant mycorrhizal
benefits under global change remain poorly understood.  We
synthesized 1,646 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. 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 colonization 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. 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.