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Northwest Fisheries Science Center (NWFSC) Fish Ecology FE - Watershed


Potential Habitat Improvement
Potential for Habitat Improvement in the Columbia River Basin
Basin-wide analysis of potential to improve tributary habitats in the Columbia River basin through restoration of habitat-forming processes.

Identification of geomorphological target conditions for river restoration is typically based on locally measured reference conditions, yet few reference sites remain in much of the 630,000 km2 Columbia River Basin, USA. Therefore, we predicted reference conditions throughout the basin based on key reach-scale variables, which we empirically derived from a limited number of reference sites. We developed a GIS data set that depicts pre-settlement riparian vegetation in the Columbia River Basin to guide stream restoration for endangered salmon. However, the modeled riparian species composition was quite inaccurate, so we are not distributing these model results.

Methods: We first created a data layer of historic riparian vegetation information from survey notes that were taken mid-19th to early 20th century during the Public Land Survey System (PLSS) conducted by General Land Office (GLO). Our reconstructed riparian vegetation data include randomly sampled basin-wide data (drainage area 200,000 km2), as well as intensively reconstructed watershed-level data (3,000 km2). Second, based on the reconstructed riparian vegetation points, which are arrayed along a 1-mile (1600 m) grid, we are developing statistical models to estimate potential historic riparian vegetation types (conifer, hardwood, willow-shrub, grass, sage) as well as the probability of occurrence of individual species at stream reach level (~ 200 m) in the basin. We examined environmental variables, such as mean annual precipitation, average minimum and maximum temperature, channel gradient, channel bankful width, floodplain width, and fine sediment supply potential, against five vegetation types and found that precipitation and temperature discriminate vegetation groups. We also developed vegetation response curves against each variable, using kernel density estimates to describe the probability of each vegetation type occurring across the range of each environmental variable.

Research Themes

Habitats to support sustainable fisheries and recovered populations
Healthy oceans, coastal waters, and riverine habitats provide the foundation for aquatic resources used by a diversity of species and society. Protecting marine, estuarine and freshwater ecosystems that support these species relies on science to link habitat condition/processes and the biological effects of restoration actions. The NWFSC provides the habitat science behind many management actions taken by NOAA Fisheries and other natural resource agencies to protect and recover aquatic ecosystems and living marine resources. The NWFSC also maintains a longstanding focus on toxic chemical contaminants, as a foundation for regional and national research on pollution threats to fisheries and protected resources.

Research Foci

Develop effective and efficient habitat restoration and conservation techniques
Maintaining and re-establishing viability and sustainability of living marine resources requires conservation and rehabilitation or restoration of habitats upon which species depend. Common habitat restoration approaches and tech-niques often presume that habitats are static features of the environment, and that creation of stable habitats is a desirable restoration strategy. However, riverine, nearshore, and marine habitats are created and sustained by dynamic landscape, climatic, and oceanographic processes and biota are adapted to changing habitats that are within the range of natural variability. Hence, current restoration strategies often have limited success, in part because they fail to recognize larger scale processes that drive habitat change, and in part because they fail to recognize intrinsic habitat potential of individual restoration sites. The main goals of this research focus are to: improve understanding of how large-scale processes create diverse and dynamic habitats that support marine and anadromous species, better understand how human activities alter habitat-forming processes and habitats, develop new restoration techniques that are compatible with sustainable habitat-forming processes, and understand the variety of actions needed to adequately conserve intact critical habitats. In addition, NWFSC’s research will improve understanding of how new and existing habitat restoration and protection techniques affect fish and habitat at multiple scales (i.e., reach, watershed, Evolutionarily Significant Unit).


Columbia River
Columbia River
related to fish habitat (terrestrial or marine)
habitat restoration


Predicted channel patterns in the Columbia River Basin, USA
Predicted riparian vegetation types in the Columbia River basin


None assigned


George Pess
Internal Collaborator
Hiroo Imaki
Timothy Beechie
Principal Investigator