CARBON AND NITROGEN STORAGE IN SOIL AND LITTER OF SOUTHERN CALIFORNIAN SEMI-ARID SHRUBLANDS.

Semi-arid shrublands of southern California, including chaparral and coastal sage, are found in widely varying elevation and microclimatic regimes and are subjected to disturbance such as fire and atmospheric N deposition that have the capacity to alter soil and litter C and N storage. Here we present a case study where soil and litter C and N were measured over 19 months in post-fire chaparral and mature coastal sage stands to assess whether differences in soil and litter C and N between these diverse shrublands could be attributed to differences in elevation, stand age, rainfall, and/or estimated N deposition exposure. Our results indicate that atmospheric N deposition exposure, either alone or in conjunction with other environmental variables (elevation, rainfall, and/or stand age), was the most frequent predictor of the spatial pattern in the soil and litter N and C variables observed.