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Watershed: effects of human activities on stream habitat
Watershed: effects of human activities on stream habitat
Problem Statement
Land use activities such as logging, farming, urban development, and other
human activities have degraded much of the freshwater habitat on which Pacific
salmon stocks depend.
Critical factors
- The degradation of freshwater habitat has contributed significantly to
the decline of Pacific salmon populations.
- Degraded freshwater habitat jeopardizes the recovery of threatened
and endangered Pacific salmon.
- The National Marine Fisheries Service (NMFS) must consider land-use
effects on freshwater habitat when it reviews habitat conservation plans (HCPs),
develops recovery plans, or provides technical assistance to other agencies
that develop land management plans, forestry or water quality regulations,
and monitoring programs.
Status of research
Within the Northwest Fisheries Science Center's (NWFSC) Watershed Program,
scientists are studying the degree to which freshwater habitats affect
abundance and population growth of salmonids in order to assist in developing
rational recovery strategies for listed salmon species. Ongoing research projects
include studying the degree to which streamside buffers of different widths
effectively protect stream ecosystem processes from logging, and examining
the effects of different land-use protocols and the presence or absence of
juvenile salmonids on food web dynamics in small streams. In addition, various
streamside buffer treatments are being evaluated with respect to the survival
and growth of trees and understory vegetation retained in buffer zones.
Additional aspects of the research entail monitoring the impacts of fine
sediment deposition and bed scouring on chinook salmon redds (i.e., the
spawning grounds or nests of the fish), evaluating the relationships between
coarse-scale habitat, land-use characteristics, and salmon populations in three
large watersheds (the Snohomish River basin in Washington, the Salmon River basin
in Idaho, and the Willamette River basin in Oregon), predicting relative salmon
abundance in areas lacking fish data, and determining how low numbers of spawning
salmon affect nutrient dynamics in streams and the productivity of salmon
populations in the Snake River basin.
Future considerations
Spawning sockeye salmon
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To mitigate human impacts on salmon habitat, additional studies are needed that
address 1) the quantitative relationships between streamside buffer
widths and actual instream conditions, 2) the impacts of land-use on stream
hydrology, sediment dynamics, and nutrient availability, 3) the influence
of habitat conditions on fish predation and salmon survival in freshwater,
and 4) the effects of multiple water-quality stresses and the cumulative
effects of individual stresses on instream habitat quality.
Key Players
Environmental Conservation (EC) Division, NWFSC
King County Department of Natural Resources
Oregon State University
University of British Columbia
University of Washington
U.S. Environmental Protection Agency
U.S. Forest Service
U.S. Fish & Wildlife Service
U.S. Geological Survey
Seattle Public Utilities
Washington Tribes
Washington Department of Natural Resources
Weyerhaeuser Company
Skagit Systems Cooperative
Tulalip Tribe
Contact: Dr. Tracy Collier, Director, EC Division (206/860-3312)
NWFSC Issue Paper EC 6506 (HQ ID 278/296/304)
Issue Papers Home
last modified 2002-07-29
Web site owner: Northwest Fisheries Science Center
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