A LAKE SEDIMENT BASED PALEOECOLOGICAL RECONSTRUCTION OF LATE HOLOCENE FIRE HISTORY AND VEGETATION CHANGE FROM GREAT BASIN NATIONAL PARK, NEVADA, USA

Analyses of charcoal, geochemistry, and pollen were conducted on a lake sediment core from Stella Lake, NV, to establish a record of fire history and vegetation change spanning the past two millennia. Charcoal accumulation rates (CHAR) indicate that fire activity was minimal from CE 1 to CE 800, but increased during the Medieval Climate Anomaly (MCA, CE 900-1300). Observed changes in catchment vegetation were driven by hydroclimate variability during the early MCA. Two increases in CHAR, which occurred during the Little Ice Age (LIA, CE 1400-1700), were interpreted as major fire events. Increased C/N, δ15N, and reduced δ13C values correspond with these severe fires, providing further evidence of catchment-scale fire events during the 15th and 16th centuries. Changes in the vegetation community followed these fire events with Pinus and Picea decreasing in abundance, and Poaceae increasing in abundance. Changes in vegetation and geochemistry were driven by fire during the LIA.