This project will continue monitoring and experimental manipulations of seed-eating animals and seed-producing plants in the Chihuahuan Desert that have been conducted continuously since 1977. The long-term records of rodents, birds, ants, and annual plants will provide information on the response of individuals, populations, and communities both to natural temporal and spatial variation and to the experimental perturbations. Manipulations begun in 1977 are still being propogated through networks of direct and indirect interactions and having new effects on the system. The study will: 1) continue to census granivore and plant populations using standardized techniques that have already provided some of the most extensive and intensive long-term data for any terrestrial ecosystem in North America; 2) convert plots that have been assigned to relatively unproductive experiments to additional replicates of the treatments that have had the most interesting effects, focusing attention on the mechanisms an dynamics of indirect interactions; and 3) work up the extensive data on rodents, emphasizing the relationships between the behavior of individuals, the dynamics of populations, and the organization of the entire assemblage of 11 common and several rare species. The investigation is a classic example of long- term ecological research at the cutting-edge of community ecology.
