This project will continue the Research Experiences for Undergraduates Site Program (REU) at the University of New Mexico in conjunction with the Sevilleta Long-Term Ecological Research Program (LTER). This project will allow eight undergraduate students per year for three summers (1999-2001) to work in direct association with the Sevilleta LTER faculty investigators. The students will participate in a coordinated research program that will address the relationships among ecosystem productivity, biodiversity, and climate fluctuations in the biome transition zones at the Sevilleta LTER site in central New Mexico. The students will receive extensive training and experience in plant and animal systematics, taxonomy, and ecological relationships that emphasize trophic structure and ecosystem productivity. Students will participate in all aspects of research, from planning new projects and collecting field data through computer data management and analysis, report preparation, and oral presentations of results. Special training in Geographical Information Systems and Global Positioning Systems will be included in the program. A seminar series in ecology and systematics (with UNM course credit) will be offered to REU participants. Students will live and work together with UNM faculty, staff, and graduate students at the Sevilleta Field Research Station (housing cost provided by UNM). Fall semester REU stipends at UNM (cost-share) will allow students to continue research projects into the autumn growing season in New Mexico.