Can manipulation of fungal endophyte diversity positively influence tall fescue pasture sustainability and ecosystem functioning?

Biodiversity is an ecological characteristic that supports ecosystem services in both managed and non-managed systems. Humans can purposefully enhance or reduce biodiversity at many levels within agricultural landscapes. While studies have evaluated the roles of plant and insect biodiversity on ecological processes, such as production and pollination, little research to date has explored effects of plant-microbe symbiotic diversity on agroecosystem functionality, in part because it is difficult, if not impossible, to experimentally control plant-microbe interactions in the field. Utilizing the well-characterized grass - vertically transmitted fungal endophyte system, we will explore whether community-level symbiotic diversity influences managed cool-season pasture ecosystem services, including yield, forage quality, plant and insect diversity, soil-to-atmosphere greenhouse gas emissions, and soil carbon sequestration. Tall fescue is a dominant forage grass of the eastern half of the U.S., covers significant acreage, and often hosts the fungal endophyte, Epichloë coenophiala. Presence and genetic strain of the endophyte can be manipulated, and several fescue cultivars containing different strains of E. coenophiala or entirely endophyte-free are available to producers today. Seed lots consist of a population of fescue, but when endophyte-infected, typically only one strain of endophyte is present within a labeled cultivar. Therefore, planted fescue pastures tend to have low endophyte symbiotic diversity. We hypothesize that increasing endophyte symbiotic diversity within the tall fescue community will enhance pasture provisioning, regulating, and supporting ecosystem services.