Filters: Tags: Schismus (X)3 results (10ms)
Short-term soil inorganic N pulse after experimental fire alters invasive and native annual plant production in a Mojave Desert shrubland.
Post-fire changes in desert vegetation patterns are known, but the mechanisms are poorly understood. Theory suggests that pulse dynamics of resource availability confer advantages to invasive annual species, and that pulse timing can influence survival and competition among species. Precipitation patterns in the American Southwest are predicted to shift toward a drier climate, potentially altering post-fire resource availability and consequent vegetation dynamics. We quantified post-fire inorganic N dynamics and determined how annual plants respond to soil inorganic nitrogen variability following experimental fires in a Mojave Desert shrub community. Soil inorganic N, soil net N mineralization, and production of...
Risk-based determination of critical nitrogen deposition loads for fire spread in southern California deserts
Fire risk in deserts is increased by high production of annual forbs and invasive grasses that create a continuous fine fuel bed in the interspaces between shrubs. Interspace production is influenced by water, nitrogen (N) availability, and soil texture, and in some areas N availability is increasing due to anthropogenic N deposition. The DayCent model was used to investigate how production of herbaceous annuals changes along gradients of precipitation, N availability, and soil texture, and to develop risk-based critical N loads. DayCent was parameterized for two vegetation types within Joshua Tree National Park, California, USA: creosote bush (CB) and pi�on?juniper (PJ). The model was successfully calibrated in...
Maps of invasive annual grasses were created using multi-season Landsat imagery over a 12 years period (2009-2020), and validated using an extensive network of plot data. Annual maps were used to identify persistent and productive populations of invasive annual grass, called hot spots, across entire Mojave Desert ecoregion. The data provided include a 12 band raster geospatial data file (.tiff) that represents classified early season invasive (ESI) grasses for each year from 2009-2020, and a single .tiff file of ESI hot spots made using the Getis-Ord Gi* Hot Spot classification method.