** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THE LONGLEAF PINE (LLP) SAVANNA ECOSYSTEM HAS GREAT POTENTIAL TO SERVE AS A MULTIFUNCTIONAL LANDSCAPE, CONTRIBUTING TO BOTH ECONOMIC AND ENVIRONMENTAL SUSTAINABILITY IN THE SOUTHEASTERN US. YET &LT;4% OF THIS ONCE EXPANSIVE ECOSYSTEM REMAINS; THUS, METHODS FOR RESTORATION AND MANAGEMENT OF LLP SAVANNA ARE CRITICAL. EXTANT LLP SAVANNAS ARE NUTRIENT POOR, LIMITING PRODUCTIVITY OF BOTH THE LLP TIMBER TREES AS WELL AS THE UNDERSTORY PREVENTING SUCCESSFUL RESTORATION OF THE PLANT-FIRE FEEDBACK LOOP. WITH THIS SEED GRANT, WE AIM TO BEGIN TO UNDERSTAND THE ROLE OF TWO KEY MICROBIAL SYMBIOSES IN PROMOTING NUTRIENT AVAILABILITY AND ULTIMATELY IMPROVING FUNCTIONING OF THE LLP ECOSYSTEM: (1) RHIZOBIAL BACTERIA CRITICAL FOR NITROGEN FIXATION IN LEGUMES (PLANTS IN FABACEAE) AND (2) MYCORRHIZAL FUNGI CRITICAL FOR PHOSPHOROUS UPTAKE IN MANY PLANT LINEAGES. OUR RESEARCH WILL ADVANCE CURRENT PRIORITIES OF BNRE SUSTAINABLE AGROECOSYSTEMS (A1451) BY FOCUSING ON IMPROVING PRODUCTIVITY IN MANAGED LLP SAVANNA. THIS SEED GRANT WILL SUPPORT (1) OBSERVATIONAL DATA COLLECTION, (2) ESTABLISHMENT OF AN EXPERIMENTAL PLATFORM MANIPULATING THE FREQUENCY OF NUTRIENT-BASED MUTUALISMS, AND (3) THE FORMATION OF A NETWORK OF SITES FOR FUTURE LLP RESEARCH. THIS WORK WILL LEAD TO INCREASED UNDERSTANDING OF NUTRIENT-BASED MUTUALISMS WITH THE LONG-TERM GOALS OF ENSURING ADEQUATE FUEL FOR FIRE SPREAD AND ENHANCING UNDERSTORY AND TREE PRODUCTION, AND WILL FORM THE BASIS FOR A FUTURE PROPOSAL FOR A STANDARD USDA GRANT. OVERALL, WE AIM TO YIELD INNOVATIVE AND ENVIRONMENTALLY-SOUND MANAGEMENT STRATEGIES FOR THE LLP ECOSYSTEM, THEREBY IMPROVING THE ENVIRONMENTAL HEALTH AND SUSTAINABILITY OF OUR NATURAL RESOURCE BASE.