Effects of nutrient addition on endophyte-associated grass invasion in a long-term, old-field community experiment

Such endophytes may increase host invasiveness in the non-native, introduced ranges. However, the costs and benefits for the host can vary with the abiotic and biotic growing conditions, and the endophyte may become locally or temporally extinct when costs outweigh benefits.

Our long-term field experiment involved seven Schedonorus pratensis (meadow fescue) cultivars hosting Epichloë uncinata endophyte, which represent host-grass populations with different genetic background and Epichloë infection levels. In the first six years, the host grasses persisted but did not become invasive in an old-field plant community, regardless of their endophyte infection frequency. We hypothesized that increasing nutrient availability would decrease endophyte costs and thus increase the host’s success and abundance.