EPSCoR - Alaska Adapting to Changing Environments

EPSCoR - Alaska Adapting to Changing Environments

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Catchment response to bark beetle outbreak and dust-on-snow in the Colorado Rocky Mountains

Since 2002, the headwaters of the Colorado River and nearby basins have experienced extensive changes in land cover at sub-annual timescales. Widespread tree mortality from bark beetle infestation has taken place across a range of forest types, elevation, and latitude. Extent and severity of forest structure alteration have been observed through a combination of aerial survey, satellite remote-sensing, and in situ measurements. Additional perturbations have resulted from deposition of dust from regional dry-land sources on mountain snowpacks that strongly alter the snow surface albedo, driving earlier and faster snowmelt runoff. One challenge facing past studies of these forms of disturbance is the relatively small magnitude of the disturbance signals within the larger climatic signal. The combined impacts of forest disturbance and dust-on-snow are explored within a hydrologic modeling framework. We drive the Distributed Hydrology Soil and Vegetation Model (DHSVM) with observed meteorological data, time-varying maps of leaf area index and forest properties to emulate bark beetle impacts, and parameterizations of snow albedo based on observations of dust forcing. Results from beetle-killed canopy alteration suggest slightly greater snow accumulation as a result of less interception and reduced canopy sublimation and evapotranspiration, contributing to overall increases in annual water yield between 8% and 13%. However, understory regeneration roughly halves the changes in water yield. A purely observation-based estimate of runoff coefficient change with cumulative forest mortality shows comparable sensitivities to simulated results; however, positive water yield changes are not statistically significant (p 6 0.05). The primary hydrologic impact of dust-on-snow forcing is an increased rate of snowmelt associated with more extreme dust deposition, producing earlier peak streamflow rates on the order of 1–3 weeks. Simulations of combined bark beetle and dust-on-snow produced little compounding effects, due to the relatively exclusive nature of their impacts. Potential changes in water yield and peak streamflow timing have important implications for regional water management decisions.

Data and Resources

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    Website :: Publisher Website

    http://onlinelibrary.wiley.com/doi/10.1111/gcb.12829/full

Status: Complete
Type: Project
Data Types: Report
Primary Contact
Pyare, Sanjay
Email: sanjay.pyare@uas.alaska.edu
Work: 907-796-6007
Primary Agency
EPSCoR - Alaska Adapting to Changing Environments
Type
Academic

Funding Agency
EPSCoR - Alaska Adapting to Changing Environments
Type
Academic

Other Agencies
National Science Foundation

ISO Topics
biota

Geo-keywords
Southeast

Collection
Southeast Test Case

Direct Record Link
http://setc.portal.gina.alaska.edu/catalogs/11712-catchment-response-to-bark-beetle-outbreak-and
  • 01c8ceef3d596f40f05bf496ca00d929
    Published by Lisa
    2016-09-15 10:14:54 -0800
  • 01c8ceef3d596f40f05bf496ca00d929
    Updated by Lisa
    2016-09-15 10:14:41 -0800
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    Updated by Lisa
    2016-09-15 10:14:08 -0800
  • 01c8ceef3d596f40f05bf496ca00d929
    Updated by Lisa
    2016-09-15 10:12:07 -0800
  • 470f70ddabc3d336a04110c5468ab053
    Updated by Nicolette
    2016-09-14 13:13:16 -0800
  • 470f70ddabc3d336a04110c5468ab053
    New record created
    2016-09-14 13:12:58 -0800
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