Sevilleta research is designed to understand the individual and interactive effects of 3 key system components: abiotic pulses, ecosystem processes, and biotic responses. Abiotic pulses and constraints include (1) seasonal, annual, and decadal variations in climate, (2) geomorphology, soil texture, structure and depth, and surface and riparian hydrology, and (3) season, periodicity, and intesity of flow. These abiotic factors affect dymnamics of biogeochemical pools and cycles; water input, storage, use and loss; and patterns and controls on gross and net primary production. Biotic responses to the coupling of these abiotic factors and ecosystem processes include dynamics and stability in the distribution, abundance, and diversity of plant and animal populations and communities. Projects in green are new research projects that will be implemented through the Sevilleta LTER.