GRASSLANDS AND RANGELANDS PROVIDE MANY VITAL ECOSYSTEM SERVICES, INCLUDING MAINTENANCE OF BIODIVERSITY, CARBON SEQUESTRATION, BIOFUEL PRODUCTION, AND GRAZING AND FORAGE FOR LIVESTOCK AND WILDLIFE. HOWEVER, MANY GRASSLANDS AND RANGELANDS ARE HIGHLY DEGRADED AND REQUIRE MANAGEMENT TO ENHANCE THESE SERVICES. DESPITE EFFORTS TO RESTORE AND IMPROVE THEM, MANY MANAGED GRASSLANDS ARE LESS DIVERSE THAN UNDISTURBED GRASSLANDS, LACK NATIVE SPECIES THAT PROVIDE FORAGE, AND ARE DOMINATED BY INVASIVE SPECIES. A BETTER UNDERSTANDING OF THE FACTORS THAT DRIVE NATIVE AND INVASIVE SPECIES ESTABLISHMENT IN GRASSLANDS IS VITAL TO MANAGEMENT OF THESE IMPORTANT ECOSYSTEMS.RECENT STUDIES SUGGEST THAT THE SOIL MICROBIAL COMMUNITY MAY PLAY A KEY ROLE IN THE ESTABLISHMENT OF DESIRABLE NATIVE SPECIES IN MANAGED GRASSLANDS. RHIZOBIA (NITROGEN-FIXING BACTERIA THAT GIVE PLANTS NITROGEN IN EXCHANGE FOR CARBON) ARE PART OF THE MICROBIAL COMMUNITY, AND MAY PLAY A ROLE IN THE SUCCESS OF THE NATIVE AND INVASIVE LEGUME SPECIES THAT THEY ASSOCIATE WITH. IN THIS PROJECT, WE WILL EXAMINE DIFFERENCES IN THE RHIZOBIUM COMMUNITY BETWEEN UNDISTURBED, DISTURBED, AND RESTORED GRASSLANDS USING GENOMIC APPROACHES AND GREENHOUSE EXPERIMENTS. ADDITIONAL GREENHOUSE AND FIELD EXPERIMENTS WILL EXAMINE PLANT RESPONSES TO RHIZOBIA, TO DETERMINE WHETHER NATIVE AND INVASIVE PLANTS DIFFER IN THE BENEFITS THEY DERIVE FROM RHIZOBIA COMMUNITIES IN DIFFERENT GRASSLAND TYPES. RESULTS FROM THIS PROJECT MAY HELP GUIDE LAND MANAGEMENT PRACTICES, AS LAND MANAGERS COULD MANIPULATE RHIZOBIUM COMMUNITIES IN GRASSLANDS TO ENHANCE THE SUCCESS OF NATIVE SPECIES AND MANAGE INVADERS. THIS WILL LEAD TO MORE DIVERSE GRASSLANDS WITH LONG-LIVED NATIVE SPECIES THAT ENHANCE THE QUALITIES OF THESE SYSTEMS FOR LIVESTOCK AND WILDLIFE.