Fungal effects on plant-plant interactions contribute to grassland plant abundances: evidence from the field

1. Plant-fungal interactions can have strong effects on plant abundances, both through direct effects on plant performance and indirect effects on competition and facilitation. Most evidence linking fungi to plant abundances derives from direct fungal effects on initial growth, with little evidence linking fungal effects on plant-plant interactions in intact communities to plant abundances for any plant life history stage. 2. We transplanted 4320 individuals belonging to 18 plant species into plots where we removed neighbouring vegetation and suppressed fungi using fungicide in a factorial design. We monitored plant survival and growth for three years, using this data to test whether fungi had net effects on how plant-plant interactions affected different plant life history components (initial survival/growth, adult survival/growth). We then tested whether these indirect fungal effects or direct fungal effects on plant performance best explained plant commonness (frequency of occurrence...