Shifts in plant community composition weaken the negative effect of nitrogen addition on community-level arbuscular mycorrhizal fungi colonization

Nitrogen addition affects plant-arbuscular mycorrhizal fungi
(AMF) association greatly. However, although the direct effect of
nitrogen addition on AMF colonization has received investigation, its
indirect effect through shifts in plant community composition has
never been quantified. Based on a 7-year nitrogen addition experiment
in an alpine meadow of Qinghai-Tibetan Plateau, we investigated the
effects of nitrogen addition on both plant community, AMF diversity
and colonization, and disentangled the direct and indirect effects of
nitrogen addition on community AMF colonization. At plant species
level, nitrogen addition significantly decreased root colonization
rate and altered AMF community composition, but with no significant
effect on AMF richness. At plant community level, plant species
richness and AMF colonization rate decreased with nitrogen addition.
Plant species increasing in abundance after nitrogen addition were
those with higher AMF colonization rates in natural condition...