N saturation symptoms in chaparral catchments are not reversed by prescribed fire.
Fire is a critical ecosystem process in many landscapes and is particularly dominant in the chaparral shrublands of southern California which are also exposed to high levels of atmospheric N deposition. Few studies have addressed the combined effects of these two disturbance factors. In this study we evaluate the hydrologic and biogeochemical response of a control and a prescribed burn catchment over a 15-year period. Streamwater nitrate concentrations and export in the burned catchment were higher than those in the unburned catchment for 7-10 years after the burn and concentrations remained high in both catchments during the entire study. Therefore, fire is not an effective mitigation tool for N deposition in these semi-arid systems. Additionally, the extended N export in this system indicates that chaparral ecosystems do not recovertheir N retention capabilities as rapidly as humid systems do when subjected to disturbance.
Meixner
T
T
Department of Hydrology and Water Resources, University of Arizona, Tucson, Arizona 85721, USA. tmeixner@hwr.arizona.edu
Fenn
M E
ME
Wohlgemuth
P
P
Oxford
M
M
Riggan
P
P
D000393:Air Pollutants; D002140:California; D003247:Conservation of Natural Resources; D004463:Ecology; D017753:Ecosystem; D004777:Environment; D004784:Environmental Monitoring; D005390:Fires; D009584:Nitrogen / Q000737:chemistry*; D010944:Plants; D014197:Trees
D000393:Air Pollutants; D009584:Nitrogen