Manipulating cultivar diversity: Impacts to arthropod communities in pasture agroecosystems

Biodiversity in pasture agroecosystems can provide valuable ecosystem services. One way to potentially enhance biodiversity and services in this setting is by increasing genetic diversity within species. Tall fescue (Lolium arundinaceum) is an intriguing species for investigating impacts of cultivar diversity due to its cultivar-specific associations with distinct strains of its fungal endosymbiont, Epichloë coenophiala. We leveraged an experimental array containing a gradient of fescue/endophyte diversity to determine its impacts on ant (Formicidae) communities, since ants are numerically dominant and functionally important arthropods in pasture ecosystems. Contrary to our expectations, neither symbiotic diversity, cultivar composition, nor chemical types produced by Epichloë endophytes significantly impacted ant communities. The observed diversity (quantified as richness and Hill numbers), abundance, and community composition of ants did not differ significantly between treatments. This trend was consistent across year and season. Our results suggest that diversity of cultivars and their associated endophytes in fescue-based pasture systems does not strongly impact ant communities or their services.