RANGE AGROECOSYSTEMS CAN BE PARTICULARLY SENSITIVE TO RAINFALL VARIABILITY, SINCE UNLIKE MOST OTHER CONTEMPORARY AGRICULTURE THEY CANNOT BE ECONOMICALLY IRRIGATED IN RESPONSE TO DROUGHT. CONSEQUENTLY, FORAGE AVAILABLE FOR RANGE ANIMALS CAN VARY DRAMATICALLY WITH RAINFALL YEAR TO YEAR. AS SUCH, RANCHERS OFTEN NEED TO BASE STOCKING RATES ON THE LOWER END OF FORAGE PRODUCTIVITY TO AVOID LOSSES IN LESS PRODUCTIVE YEARS, REDUCING THEIR ABILITY TO CAPITALIZE ON HIGH-PRODUCTIVITY YEARS.MY OVERARCHING GOAL IS TO EXPAND ECOLOGICAL KNOWLEDGE OF TEMPORAL DYNAMICS IN RANGELANDS TO BETTER PREDICT AND MANAGE FORAGE PRODUCTIVITY. RECENT WORK SUGGESTS THAT PREVIOUS-YEAR RAINFALL IS AS IMPORTANT AS CURRENT-YEAR RAINFALL FOR RANGELAND DYNAMICS, AND MAY PROMOTE COEXISTENCE OF DIFFERENT FORAGE SPECIES. TO TEST THE EFFECTS OF LAGGED PRECIPITATION ON CALIFORNIA RANGELANDS, I WILL CONDUCT A FIELD EXPERIMENT WITH RAINFALL MANIPULATION TO PARAMETERIZE MODERN COEXISTENCE THEORY MODELS FOR COMMUNITIES OF PERENNIAL AND ANNUAL GRASSES UNDER DIFFERENT PATTERNS OF DRY AND WET YEARS. TO EXTEND THESE COMMUNITY MODELS TO CONSEQUENT PRODUCTIVITY AND FORAGE AVAILABILITY, I WILL TEST MODEL PREDICTIONS ON LONG-TERM VEGETATION AND PRODUCTIVITY DATA FROM THE SITE. THIS PROJECT ALIGNS WITH THE AFRI PRIORITY AREA OF BIOENERGY, NATURAL RESOURCES, AND ENVIRONMENT BY INCREASING OUR UNDERSTANDING OF RANGELAND DYNAMICS AND THE ROLE OF PLANT DIVERSITY IN THE SUSTAINABLE MANAGEMENT OF THESE SYSTEMS. ADDITIONALLY, THE PROJECT DIRECTLY SUPPORTS THE POSTDOCTORAL DEVELOPMENT OF THE PD, CHHAYA WERNER, IN DEVELOPING TECHNICAL RESEARCH AND MODELING SKILLS AND COLLABORATING WITH RANGELAND MANAGERS AND EDUCATING AND MENTORING STUDENTS IN RANGELAND SCIENCE. I WILL COMMUNICATE RESEARCH FINDINGS THROUGH PEER-REVIEWED PAPERS, AT CONFERENCES FOCUSED ON THE INTERACTIONS BETWEEN LAND MANAGERS AND RESEARCHERS SUCH AS THE CALIFORNIA SOCIETY FOR ECOLOGICAL RESTORATION AND THE NATURAL AREAS ASSOCIATION CONFERENCE, AND DIRECTLY TO LOCAL RANCHERS AT THE SIERRA FOOTHILL RESEARCH AND EXTENSION CENTER'S FIELD DAY FOR RANCHERS.