Response of a Brook Trout Population and Instream Habitat to a Catastrophic Flood and Debris Flow

Response of a Brook Trout Population and Instream Habitat to a Catastrophic Flood and Debris Flow

In June 1995, a massive flood and debris flow impacted fish and habitat along the lower 1.9 km of the Staunton River, a headwater stream located in Shenandoah National Park, Virginia. In the area affected by debris flow, the stream bed was scoured and new substrate materials were deposited, trees we...

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Bibliographic Details
Published in:Transactions of the American Fisheries Society (1900) Vol. 131; no. 4; pp. 718 - 730
Main Authors: Roghair, Craig N., Dolloff, C. Andrew, Underwood, Martin K.
Format: Journal Article
Language:English
Published: Bethesda, MD Taylor & Francis Group 01-07-2002
American Fisheries Society
Subjects:
Agnatha. Pisces
Animal and plant ecology
Animal, plant and microbial ecology
Animals
Autoecology
Biological and medical sciences
Fundamental and applied biological sciences. Psychology
Vertebrata
United States
North America
Virginia
America
Salmonidae
Annual variation
Environmental factor
Population structure
Spatial variation
Freshwater environment
Vertebrata
Salvelinus fontinalis
Pisces
Environment impact
Plant origin
Stream
Scour
Debris
Flood(streams)
Population density
Ecological disaster
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Summary:In June 1995, a massive flood and debris flow impacted fish and habitat along the lower 1.9 km of the Staunton River, a headwater stream located in Shenandoah National Park, Virginia. In the area affected by debris flow, the stream bed was scoured and new substrate materials were deposited, trees were removed from a 30‐m‐wide band in the riparian area, and all fish were eliminated. In the area that was unaffected by debris flow, habitat was moderately altered by the flood and fish populations persisted at decreased densities. Basinwide fish population and habitat surveys provided data to compare (1) the pre‐ and postevent population densities of brook trout Salvelinus fontinalis and instream habitat conditions and (2) postevent population density, brook trout growth, and instream habitat in the debris‐flow‐affected and unaffected areas. By June 1998, brook trout had recolonized the entire debris‐flow‐affected area, and population density exceeded preevent levels. Brook trout growth was significantly greater in the debris‐flow‐affected area than in the unaffected area through fall 1998, but it was not significantly greater in 1999. Population density appeared to have a negative influence on fish growth. A 1995 postevent habitat survey revealed increases in the number of pools and riffles and substrate size and decreases in pool and riffle surface area and depth. By 1999, the total number, surface area, and depth of pools and riffles had returned to near preevent levels and substrate size had decreased. Between 1995 and 1999, the amount of large woody debris increased in the debris‐flow‐unaffected area, where riparian trees had remained intact, and decreased in the affected area, where riparian trees had been eliminated. A number of factors, including a relatively intact watershed and nearby source populations, allowed the Staunton River to quickly respond to this dramatic natural event. Given the proper conditions for recovery, such events are less catastrophic than activities that lead to chronic stream degradation.
Bibliography:Present address: U.S. Forest Service, Southern Research Station Center for Aquatic Technology Transfer, 1650 Ramble Road, Blacksburg, Virginia 24060, USA.
Present address: U.S. Fish and Wildlife Service, 17629 El Camino Real, Suite 211, Houston, Texas 77058, USA.
ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
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ISSN:0002-8487
1548-8659
DOI:10.1577/1548-8659(2002)131<0718:ROABTP>2.0.CO;2