News Release
|
March 11, 2009 |
Dave Peterson |
307-775-9170 |
davep@usgs.gov |
|
|
David Mott |
307-778-2931 |
dmott@usgs.gov |
Powder River Basin Stream Ecology
Study Notes Differences between Area Streams
The ecological health of the Powder River Basin varies across areas of Montana and Wyoming, a new study reports.
The U.S. Geological Survey (USGS) and Wyoming and Montana State scientists assessed streams in 2005 and 2006 in the Powder River structural basin, and report that differences can be seen between sites throughout the basin.
“Analyses of the Powder River using the small insects, snails, and worms in the streams, organisms known as macroinvertebrates, indicated a generally improving biological condition downstream from below Salt Creek to the Wyoming-Montana border, followed by a decline from the border to the confluence with the Yellowstone,” said USGS hydrologist Dave Peterson.
The reason for this pattern is not known, but continuation of the study may help discover why.
Peterson also noted that “fish communities in the Powder River were dominated by native fish such as flathead chub and catfish, with only a few introduced species. That differed from the nearby Tongue River which had a greater number of introduced species, such as common carp, black crappie, and white crappie. There are a greater number of introduced species in the Tongue River largely because of the reservoirs on the Tongue.”
The study, conducted in cooperation with the Federal/State Interagency Working Group, also established a baseline of the ecological condition of streams in the Powder River structural basin that can be used in the future.
“You can’t determine if a stream has changed if you don’t have data to describe what it was like to begin with,” Peterson said.
The USGS continues to monitor the ecological conditions of streams in the Basin, in both Wyoming and Montana, in cooperation with Federal and Wyoming and Montana State agencies.
Copies of the USGS report “Ecological Assessment of Streams in the Powder River Structural Basin, Wyoming and Montana, 2005-06,” published as Scientific Investigations Report 2009-5023 are available free of charge by calling 1–888–ASK–USGS (1–888–275–8747). The report also may be viewed online at: http://water.usgs.gov/pubs/sir/2009/5023/.
USGS provides science for a changing world. For more information visit www.usgs.gov
***www.usgs.gov***