Prevailing freshwater conservation approaches in the USA stem from policy-based ecosystem management directives, science-based gap analyses, and legal interpretations of critical habitats. In California, there has been no systematic prioritization of freshwater habitats critical to the persistence of anadromous salmonid populations.
Anadromous salmonids provide an optimal focal species for conservation prioritization of freshwater habitats in California owing to their flagship, umbrella and keystone status.
The Navarro River is a key watershed for both Endangered Species Act and Clean Water Act recovery efforts in the state of California. This watershed serves as a case study in the use of iterative discriminant analysis to objectively classify freshwater habitats critical to the persistence of two species of threatened anadromous salmonids, steelhead (Oncorhynchus mykiss) and coho (Oncorhynchus kisutch).
Riverscape parameters were used initially to define suitable habitat for focal species; subsequent refinement accounted for human disturbance within the watershed. Results from this study identify 22.1 km of riverine habitat critical to the persistence of coho salmon in the Navarro River watershed, which need active conservation or restoration; it also identified an additional 269.4 km of riverine habitat in need of protection for its aquatic habitat values.