This proposal, between Drs. James E. Ellis and Gerald M. Ward of the Colorado State University, and Dr. Ren Jizhou of the Gansu Grassland Ecological Institute, seeks to apply ecological systems analysis to arid and semiarid grazinglands in the People's Republic of China with a regional modeling approach to the analysis and management of grazinglands in Gansu Province. Over half of China consists of such grazinglands, where poor management and over-exploitation have advanced environmental deterioration and contributed to desertification. The researchers will combine accepted ecological principles with data from existing extensive data bases (aerial photos; soils maps; climatic maps; and remote-sensed imagery, particularly vegetation-index values derived from Multi-Spectral Scanner, Advanced Very High Resolution Radiometry and other imagery). Their grazingland analysis system (GRAS) will simulate the outcome of alternate management strategies on productivity, stability, and sustainability. This project is jointly sponsored by NSF and by the National Natural Science Foundation of China.