Sevilleta LTER NPP Quadrat Data 1999

Net primary production (NPP) is a fundamental ecological variable that measures 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 of the community to a wide range of ecological processes. A long-term study has been established at the Sevilleta LTER to monitor net primary production across four distinct ecosystems: creosote dominant shrubland, black grama dominant grassland, juniper-savannah and pinyon-juniper woodland. While measures of both below and above ground biomass are important in estimating NPP, the described study focuses on estimating above ground biomass production (ANPP). ANPP is equal to the change in plant mass, including any losses to death and decomposition, over a given period of time. To measure this change, above ground biomass production (ANPP) is sampled three times a year (winter, spring and fall) for all species at each of the four sites. In addition, volumetric measurements are obtained from permanent plots at the three sites to build regressions correlating biomass and volume