Novus participant Paul Dunnette, along with Novus steering committee members Phil Higuera and Kendra McLauchlan and colleagues recently published an article in New Phytologist titled “Biogeochemical impacts of wildfires over four millennia in a Rocky Mountain subalpine watershed. ”
The study analyzes a lake sediment core from Chickaree Lake, Colorado that spans the last ~4,250 years. Their results show that high-severity fires were followed by increased nitrogen isotope ratios and decreased concentrations of carbon and nitrogen. These trends reflect forest floor destruction, terrestrial C and N losses, and erosion. Ratios of carbon to nitrogen (C:N) remained low for 20-50 years following fire, indicating reduced terrestrial organic matter in the lake. Sediment nitrogen isotope trends 50-70 years following fire events suggested reduced N availability during stand development. Additionally, the magnitude of these trends was directly scaled to the severity of the fire event.
Over the past 4,000 years, return intervals of high-severity fires were long enough to allow for full ecosystem recovery; however, predicted future conditions of warmer and drier summers, which may lead to increased fire severity and/or shorter return intervals could compromise long-term ecosystem resilience in this region.
Full citation: Dunnette PV, PE Higuera, KK McLauchlan, KM Derr, CE Briles, MH Keefe (2014) Biogeochemical impacts of wildfires over four millennia in a Rocky Mountain subalpine watershed. New Phytologist. DOI: 10.1111/nph.12828