** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** SUMMARYRANGELANDS SUPPORT THE PASTORAL LIVELIHOOD AND FOOD SECURITY OF BILLIONS OF PEOPLE GLOBALLY WHILE PROVIDING CRUCIAL ECOSYSTEM SERVICES,SUCH ASBIODIVERSITY AND PRIMARY PRODUCTIVITY. HOWEVER,WIDESPREAD BIOLOGICAL INVASIONS BY EXOTIC PLANT SPECIES ARE DEGRADING THE BIODIVERSITY AND ECOSYSTEM FUNCTIONING (BEF) OF RANGELAND SYSTEMS AT TREMENDOUS ECONOMIC COSTS, CREATING AN URGENT NEED FOR MANAGEMENT ACTIONS THAT PROVIDE SUSTAINABLE SOLUTIONS TO RANGELANDPLANT INVASIONS.UNDERSTANDING THE ECOLOGICAL PROCESSES THAT DRIVE PLANT INVASIONS IS THE CRUCIAL FIRST STEP TOWARDS SUSTAINABLE CONTROL.A POWERFUL APPROACH FOR GAINING THIS UNDERSTANDINGIS TO EXPERIMENTALLYEVALUATE HOW BIOTIC AND ABIOTIC PROCESSES AFFECT INVASIVE SPECIES IN THEIR NATIVE VS. NON-NATIVE RANGES.THIS BIOGEOGRAPHICAL APPROACH POISES LAND MANAGERS TO CONTROL PLANT INVASIONS BY EITHER MIMICKING POPULATION CONTROLS THAT ARE MORE EFFECTIVE IN THE NATIVE RANGE, OR BY DISRUPTING POSITIVE FEEDBACKS PRESENT MAINLY IN THE NON-NATIVE RANGE.HOWEVER,THE VAST MAJORITY OF STUDIES ON INVASIVE SPECIES ECOLOGY AND MANAGEMENT HAVE BEEN CONDUCTED SOLELY WITHIN THE NON-NATIVE RANGE OF INVADERS, WHERE THEY ARE MOST PROBLEMATIC AND BEHAVE MUCH DIFFERENTLY THAN IN THEIR NATIVE RANGE.THIS LACK OF BIOGEOGRAPHICAL CONTEXT LIMITS OUR FUNDAMENTAL KNOWLEDGE OF PLANT INVASIONS AND PERPETUATES THE DIFFICULTY OF SUSTAINABLY CONTROLLING RANGELAND WEEDS. FOLLOWING THIS, THE OVERARCHING GOAL OF OUR PROPOSAL IS TO USE AN EXPERIMENTAL, BIOGEOGRAPHICAL APPROACH TO ADVANCE OUR MECHANISTIC UNDERSTANDING OF HOW BIOTIC AND ABIOTIC PROCESSES CONTRIBUTE TO THE INVASION AND SUSTAINABLE CONTROL OFBROMUS TECTORUM- AN ANNUAL GRASS NATIVE TO EURASIA BUT EXOTIC AND EXTREMELY INVASIVE ACROSS WESTERN NORTH AMERICAN RANGELANDS.OUR PRIMARY RESEARCH OBJECTIVES ARE TO: 1) QUANTIFY HOW BIOTIC (INSECT HERBIVORY, PLANT-FUNGAL INTERATIONS, CATTLE GRAZING) AND ABIOTIC (FIRE, MECHANICAL SOIL DAMAGE) PROCESSES INDEPENDENTLY AND JOINTLY AFFECTB. TECTORUMABUNDANCE AND BEF IN THE NATIVE (EURASIA) AND NON-NATIVE (USA) RANGES; AND 2) IDENTIFY COMBINATIONS OF MANAGEMENT ACTIONS THAT LEAD TO SUSTAINABLE, PROCESS-BASED MANAGEMENT OF LOCALB. TECTORUMABUNDANCE AND BEF.TO ACHIEVE OUR FIRST OBJECTIVE, WE WILL REPLICATE SIMULTANEOUS, COORDINATED EXPERIMENTS IN ACTIVELY GRAZED, MULTI-USE RANGELANDS IN THE NATIVE (ITALY, HUNGARY, IRAN) AND NON-NATIVE (UTAH, NEVADA, IDAHO, OREGON) RANGES OFB. TECTORUM. THESE EXPERIMENTS WILL MANIPULATE KEY BIOTIC (PLANT-FUNGAL INTERACTIONS, INSECT HERBIVORY, CATTLE GRAZING) AND ABIOTIC (FIRE, MECHANICAL SOIL DAMAGE) PROCESSES. TO ACHIEVE OUR SECOND OBJECTIVE, WE WILL DEVELOP A STRAIGHTFORWARD GRAPHICAL TOOL THAT CLEARLY DEPICTS THE EFFECTS OF EXPERIMENTAL TREATMENT COMBINATIONS (WHICH CAN BE THOUGHT OF AS POSSIBLE MANAGEMENT ACTIONS) ON B. TECTORUM ABUNDANCEAND BEF SIMULTANEOUSLY. THIS PROPOSED RESEARCH WILL INCREASE OUR FUNDAMENTAL UNDERSTANDING OF THE ECOLOGICAL PROCESSES THAT DRIVEB. TECTORUMINVASION AND BEF IN LOCAL PLANT COMMUNITIES, AND THEN TRANSLATE THIS BASIC UNDERSTANDING TO ADAPTIVE MANAGEMENT ACTIONS THAT CONTROLB. TECTORUMABUNDANCE WHILEINCREASING BEF. TO ACCOMPLISH OUR OBJECTIVES, WE HAVE ASSEMBLED A DYNAMIC TEAM OF INTERNATIONAL COLLABORATORS BASED IN THE NATIVE (EURASIA) AND NON-NATIVE (USA) RANGES OFB. TECTORUM, WITH DECADES OF COLLECTIVE EXPERIENCE CONDUCTING BIOGEOGRAPHICAL RESEARCH ON THE ECOLOGY AND MANAGEMENT OF INVASIVE PLANT SPECIES. WE WILL MAXIMIZE GAINS ON OUR RESEARCH BY CREATING AN ADVISORY COMMITTEE WITH MEMBERS FROM DIVERSE ORGANIZATIONS, INCLUDING INTERNATIONAL NON-GOVERNMENTAL ORGANIZATIONS, FEDERAL AND STATE LAND MANAGERS, PRIVATE LANDOWNERS, AND RANGE PROFESSIONALS. WE WILL SEEK ONGOING GUIDANCE FROM THE ADVISORY COMMITTEE ON THE FEASIBILITY OF THE BASIC AND APPLIED COMPONENTS OF OUR PROJECT, AS WELL AS THE MOST EFFECTIVE OUTLETS FOR DISSEMINATING OUR FINDINGS.