Modeling regional variation in net primary production of pinyon–juniper ecosystems

Spatial dynamics of carbon fluxes in dryland montane ecosystems are complicated and may be influenced by topographic conditions and land tenure. Here we employ a modified version of the Carnegie Ames Stanford Approach (CASA) ecosystem model to estimate annual net primary production (NPP) at a fine spatial resolution (30m) in pinyon–juniper (P–J) woodlands of the Colorado Plateau. NPP estimated by CASA was generally comparable to validation data from a statistical NPP model and field observations. We then compared modeled NPP results with spatial layers of topography and managed grazing to assess the influences of these factors on NPP. At the regional scale, there was a positive correlation between elevation and NPP (r²=0.20, p