GRASSLAND ECOSYSTEMS COVER ROUGHLY 40% OF THE UNITED STATES AND CONSIST OF A MIXTURE OF NATIVE-DOMINATED RANGELANDS AND HUMAN DERIVED PASTURE SYSTEMS. GRASSLANDS ARE IMPORTANT TO HUMANS AS A SOURCE OF FORAGE FOR GRAZING ANIMALS, ALTERNATIVE SOURCES OF FUEL, GREEN SPACE IN URBAN AND SUBURBAN AREAS, AND AS WILDLIFE AND POLLINATOR HABITAT. IN MANY AREAS, NATIVE DOMINATED RANGELAND HAS BEEN CONVERTED TO EITHER CROPLANDS OR GRASSLAND THAT IS DOMINATED BY NON-NATIVE ('EXOTIC' OR 'INTRODUCED' OR 'ALIEN' OR 'INVASIVE') PLANT SPECIES. THIS CONVERSION MAY HAVE GREATLY ALTERED C-CYCLING BETWEEN EXOTIC-DOMINATED SYSTEMS AND THE NATIVE SYSTEMS THEY REPLACED. FURTHERMORE, GLOBAL CHANGE MODELS PREDICT THAT PRECIPITATION AMOUNTS AND FREQUENCIES WILL CHANGE IN THE FUTURE, WHICHMAKES IT NECESSARY TO EVALUATE HOW ALTERED PRECIPITATION WILL AFFECT C CYCLING IN RANGELANDS, ANDHOW ALTERED PRECIPITATION MIGHT DIFFERENTIALLYAFFECT NATIVE AND NON-NATIVE DOMINATED RANGELANDS. BELOWGROUND PRODUCTION OFTEN EXCEEDS ABOVEGROUND PRODUCTION IN GRASSLAND SYSTEMS, AND A BETTER UNDERSTANDING OF HOW HUMAN ACTIONS ARE IMPACTING SOIL C IS NECESSARY. WE PROPOSE TO ADDRESS A FUNDAMENTAL INFORMATION GAP ON HOW BELOWGROUND C-CYCLING IS IMPACTED BY THE REPLACEMENT OF NATIVE RANGELANDS WITH NON-NATIVE COMMUNITIES UNDER CURRENT AND ALTERED PRECIPITATION LEVELS.