HR: 11:20h
AN: GC32A-05    [Abstracts]
TI: Secondary Effects of Climate Change on Streamflow Through Wildfire: Compensating or Exacerbating?
AU: * Luce, C
EM: cluce@fs.fed.us
AF: USDA Forest Service Rocky Mountain Research Station, 322 E Front St, Boise, ID 83702, United States
AB: Changes to snow accumulation in mountains have yielded two noteworthy phenomena: A shift in the timing of snowmelt and streamflow and increased occurrence and severity of wildfires. Wildfire, in turn, produces feedbacks on the snow accumulation and melt process that further alters streamflow generation processes and future prospects for vegetation. An important question is whether increased wildfire will exacerbate or ameliorate climate related changes. Vegetation reduction experiments in small watersheds (O~1-5 km²) suggest we should expect greater snow accumulation and reduced evapotranspiration following wildfire, however they also show slight advances in the timing of snowmelt peaks. Recent large scale wildfires are providing an opportunity to see how the secondary effects of climate change through wildfire play out at scales comparable to those where direct changes have been assessed. In the Boise River basin, two mountain watersheds on the order of 2,000 km² each form a paired watershed experiment with approximately 45% of one basin burned and nearly no fire in the other. With sixty years of calibration, and twelve years post fire, significant increases in annual water yield on the order of 5% were found. Increases primarily occurred in winter and early spring, however, exacerbating the shift in flow timing for this high elevation basin. The tradeoff in timing and yield produced dramatically lower flows in early summer, but a slight increase in late summer, compensating for some climate change effects. Ecohydrologic theory predicts that vegetation changes accompanying increased evaporative demands should partition the losses between vegetation consumption and streamflow. The longer summer produced by these combined climate and land cover changes may yield less consumptive vegetation for the next generation.
UR: http://www.fs.fed.us/rm/boise/research/watershed/bio/luce.shtml
DE: 1630 Impacts of global change (1225)
DE: 1632 Land cover change
DE: 1807 Climate impacts
DE: 1813 Eco-hydrology
DE: 1860 Streamflow
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting