Seasonal Biomass and Seasonal and Annual NPP for the Fertilizer Study Site at the Sevilleta National Wildlife Refuge, New Mexico

Begun in spring 2004, this long-term study at the Sevilleta LTER examines how fertilization affects above-ground biomass production (ANPP) in a mixed desert-grassland. Net primary production is a fundamental ecological variable that quantifies rates of carbon consumption and fixation. Estimates of NPP are important in understanding energy flow at a community level as well as spatial and temporal responses to a range of ecological processes.  While measures of both below- and above-ground biomass are important in estimating total NPP, this study focuses on above-ground net primary production (ANPP). Above-ground net primary production is the change in plant biomass, including loss to death and decomposition, over a given period of time. Volumetric measurements are made using vegetation data from permanent plots (SEV155, "Nitrogen Fertilization Experiment (NFert): Net Primary Productivity (NPP) Study") and regressions correlating species biomass and volume constructed using seasonal harvest weights from SEV157, "Net Primary Productivity (NPP) Weight Data." This site was burned by a prescribed fire in 2003.