Mycorrhizal feedbacks generate positive frequency dependence accelerating grassland succession

1. Plant mutualists including arbuscular mycorrhizal (AM) fungi have been postulated as being important drivers of plant community diversity and succession. Late successional plants have been shown to be more responsive to AM fungi and more sensitive to AM fungal species identity, which could generate positive feedback and potentially accelerate succession.

2. We test the effect of AM fungi on plant diversity and on frequency dependence predicted by positive plant‐AM fungi feedback across a successional gradient. We created prairie mesocosms comprised of a majority early‐successional, equal abundance and a majority late successional plant species. We inoculated these mesocosms and a field restoration experiment with 14 different communities of AM fungi from late successional prairies that varied in levels of species richness.

3. Overall, we found that AM fungi increased plant diversity and this was driven by the response of late successional plant species to mycorrhizae. Our resul...