Percent change in the average C3 grass fraction (a biogeographic index based on the ratio of C3 to C4 grass) for each HUC5 watershed between historical (1971-2000) and future (2071-2100) time periods. The MC1 dynamic vegetation model was run under the CSIRO, MIROC, and Hadley climate change projections and the A2 anthropogenic emissions scenario.
Simulated mean C3 grass fraction was determined for each HUC5 watershed. Watersheds represent 5th level (HUC5, 10-digit) hydrologic unit boundaries and were acquired from the Natural Resources Conservation Service.
Background: The dynamic global vegetation model MC1 (see Bachelet et al. 2001) was used to simulate vegetation dynamics, associated carbon and nitrogen cycle, water budget, and wild fire impacts for OR, WA, AZ and NM, for a project funded by the USDA Forest Service (PNW 09-JV-11261900-003).
The MC1 model was run using historical data and future climate change projections from three general circulation models: CSIRO Mk3, MIROC 3.2 medres, and Hadley CM3. Future scenario datasets were generated through statistical downscaling using a simple anomaly method. Historical climate input data were
provided by the PRISM group (Chris Daly, Oregon State University) at a 30 arc-second (~800 m) spatial grain.
This project was funded through the U.S. Forest Service by the American Recovery and Reinvestment Act and also in part by the Western Wildland Environmental Threat Center.
