Effects of wildfire on first order stream channel morphology Yellowstone National Park, USA
Year: 1999
Type: dissertation
Abstract: The wildfires of 1988 in Yellowstone National Park have created a unique opportunity to study the effects of fire in a relatively pristine backcountry setting.These fires affected many watersheds throughout the park raising concern about the short and long-term impacts on stream ecosystems.This study examined the effects of wildfire on first-order stream channel morphology by comparing 20 stream channels located in an unburned watershed to 20 stream channels located in a watershed that experienced high intensity canopy fire.Both of these watersheds were located west of Cooke City, MT in the northeast corner of Yellowstone National Park.Variables measured included watershed area, stream gradient, bank full width, depth, sinuosity, bed material size, stream bank texture, stream bank cover, and amount of large woody debris.Stream morphology was not significantly different between unburned and burned streams nine years following the fires.Reach scale variables such as substrate size and amount of bare ground did differ significantly between the two treatments.These differences in reach scale variables did not appear to be reflected in the morphologic variables.Four possible explanations for the lack of variation between burned and unburned stream morphology are investigated.The most likely explanation is that fire did affect stream morphology initially, but recovery occurred over nine-years.A second possibility is that fire affected reach scale variables, but counter-acting processes involving substrate size and vegetative cover resulted in no net change in morphology.Finally, it is possible that the approach used in this study did not account for other reach scale variations that may influence stream morphology.The possibility that morphology was never affected by fire is discarded based on work by Robinson and Minshall (1996).Methods used in this study allowed collection of a large set of morphologic data in one field season.Techniques are efficient and reproducible by field assistants sampling in remote locations.Further studies incorporating both CHAPTER 6 DISCUSSION, SUMMARY AND CONCLUSIONS..........
Author: Kim J. Ernstrom
Language: English
Subfield: Earth-Surface Processes
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Life on land
Open Access status: green
OpenAlex ID: W933172045