The predominance of post-wildfire erosion in the long-term denudation of the Valles Caldera, New Mexico
AffiliationUniv Arizona, Dept Geosci
MetadataShow full item record
PublisherAMER GEOPHYSICAL UNION
CitationThe predominance of post-wildfire erosion in the long-term denudation of the Valles Caldera, New Mexico 2016, 121 (5):843 Journal of Geophysical Research: Earth Surface
Rights©2016. American Geophysical Union. All Rights Reserved.
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AbstractWildfires can dramatically increase erosion rates over time scales on the order of several years, yet few data firmly constrain the relative importance of post-wildfire erosion in the long-term denudation of landscapes. We tested the hypothesis that wildfire-affected erosion is responsible for a large majority of long-term denudation in the uplands of the Valles Caldera, New Mexico, by quantifying erosion rates in wildfire-affected and non-wildfire-affected watersheds over short (similar to 10(0)-10(1) years) time scales using suspended sediment loads, multitemporal terrestrial laser scanning, and airborne laser scanning and over long (similar to 10(3)-10(6) years) time scales using Be-10 inventories and incision into a dated paleosurface. We found that following the Las Conchas fire in 2011, mean watershed-averaged erosion rates were more than 1000 mu m yr(-1), i.e., similar to 10(3)-10(5) times higher than nearby unburned watersheds of similar area, relief, and lithology. Long-term denudation rates are on the order of 10-100 mu m yr(-1). Combining data for wildfire-affected and non-wildfire-affected erosion rates into a long-term denudation rate budget, we found that wildfire-affected erosion is responsible for at least 90% of denudation over geologic time scales in our study area despite the fact that such conditions occur only at a small fraction of the time. Monte Carlo analyses demonstrate that this conclusion is robust with respect to uncertainties in the rates and time scales used in the calculations.
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VersionFinal published version
SponsorsNSF [EAR-0724958, EAR-1331408]; Valles Caldera National Preserve; GSA Graduate Student Research Grant