Data from: Sick plants in grassland communities: a growth-defense trade-off is the main driver of fungal pathogen abundance

Aboveground fungal pathogens can substantially reduce biomass production
in grasslands. However, we lack a mechanistic understanding of the drivers
of fungal pathogen infection and impact. Using a grassland global change
and biodiversity experiment we show that the trade-off between plant
growth and defense is the main determinant of infection incidence. In
contrast, nitrogen addition only indirectly increased incidence via
shifting plant communities towards faster growing species. Plant diversity
did not decrease incidence, likely because spillover of generalist
pathogens or dominance of susceptible plants counteracted negative
diversity effects. A fungicide treatment increased plant biomass
production and high levels of infection incidence were associated with
reduced biomass. However, pathogen impact was context dependent and
infection incidence reduced biomass more strongly in diverse communities.
Our results show that a growth-defense trade-off is the key driver of
pathogen incidence, but pathogen impact is determined by several
mechanisms and may depend on pathogen community composition.