Principles of Salmonid Habitat Restoration

Several factors are critical to the recovery of endangered salmonids:

1. Habitat protection – which includes such things as the preservation of intact stream corridors, or the conservation of vegetative cover in upslope areas.
2. Effective watershed management – examples of which might involve the maintenance of natural fluvial-geomorphic processes, beneficial modifications to in-stream flows, or changes in the timing and quantity of water diversions.
3. Education – including community and policymaker outreach regarding the values of salmonids, requirements for survival, and options for engaging in effective land stewardship.
4. Habitat restoration – a relatively new concept that has been defined in a variety of ways. The Federal Interagency Stream Working Group (2000) defines restoration as follows: Ecological restoration is the process of returning an ecosystem as closely as possible to pre-disturbance conditions and functions. Implicit in this definition is that ecosystems are naturally dynamic... The restoration process reestablishes the general structure, function, and dynamic but self-sustaining behavior of the ecosystem.

A native plant nursery in Santa Cruz County. Installation of genetically appropriate native plants is important for successful restoration projects.

Effective restoration of salmon habitat requires rigorous multi-disciplinary assessment and planning, and an adaptive approach to restoration management. A distinguishing attribute of sustainable riparian corridors in stream systems is the dynamic interaction between hydro-geomorphic and biological processes (see the Watersheds section of this Web site for more information). Many alluvial stream reaches historically included a broad floodplain gallery forest with backwater sloughs, oxbow lakes and floodplain wetlands – all of which contributed to the maintenance of water quality and the sustainability of aquatic organisms, including salmonids. The dynamic physical processes that created these features – such as flooding and meandering – are the foundation for riparian biodiversity and stream function. Therefore, the development of criteria for sustainable riparian corridor protection, management, restoration, and monitoring must include the documentation and analysis of the hydro-geomorphic as well as the ecological processes in a given watershed.

Because human and natural impacts can affect individual habitat features as well as landscape scale processes, it is imperative that restoration efforts be planned at the appropriate spatial and temporal scale. In some cases, for example, relatively rapid and site-specific habitat improvements – such as removing a passage barrier or re-establishing riparian cover over the stream – may be the extent of the restoration effort. In other cases, the disruption of landscape scale processes is so profound that site-specific habitat restoration efforts will not be successful unless the underlying cause of the disturbance is addressed – often a large scale, long term, prospect. According to the Puget Sound Technical Recovery Team and Shared Strategy Group (2000), "strategies that emphasize the role of habitat forming processes and their interconnections are most likely to result in the persistence of aquatic habitat conditions necessary to sustain a salmonid population."

In addition to taking place at multiple temporal and spatial scales, restoration must account for the entire life history of the target species, and address habitat improvements, habitat diversification, and connectivity in the freshwater, estuarine, and ocean environments.

The National Research Council (1992) outlines the following steps for effective watershed restoration:

1. Restore the natural sediment and water regime. Regime refers to at least two time scales; the daily-to-seasonal variation in water and sediment loads, and the annual to decadal patterns of flood and droughts.
2. Restore the natural channel geometry, if restoration of the water and sediment regime alone does not.
3. Restore the natural riparian plant community, which becomes a functioning part of the channel geometry and floodplain/riparian hydrology. This step is necessary only if the plant community does not restore (if not achieved via steps above).
4. Restore native aquatic plants and animals, if they do not re-colonize on their own.

For detailed methods on implementing these steps, see the Implementation of Restoration Projects section.

References

Federal Interagency Stream Restoration Working Group (FISRWG). 1998. "Stream Corridor Restoration: Principles, Processes, and Practices." Federal Interagency Stream Restoration Working Group (FISRWG). GPO Item No. 0120-A; SuDocs No. A 57.6/2:EN 3/PT.653. ISBN-0-934213-59-3. View on-line document.

National Research Council (NRC). 1992. "Restoration of Aquatic Ecosystems: Science, Technology and Public Policy." Committee on Restoration of Aquatic Systems. National Academy Press. View on-line source.

Puget Sound Technical Recovery Team and Shared Strategy Staff Group. 2002. "Puget Sound technical recovery planning for listed salmon: Technical guidance for watershed groups in Puget Sound (draft)."

Additional Resources

California Department of Fish and Game's "California Salmonid Stream Habitat Restoration Manual" Version 3, 1998.

Trout Unlimited's "West Coast Salmon and Steelhead Protection and Restoration Action Plan" 1997.

Other Relevant Links

Institute for Fisheries Resources

NOAA Restoration Center

Pacific States Marine Fisheries Commission

Salmonid Restoration Federation

Society for Ecological Restoration

Trout Unlimited – California

Watershed Management Council

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