A case study of surrogate species in aquatic conservation planning

1. The use of surrogate species (i.e. keystones, indicators, umbrellas) has been advocated for the conservation of target taxa and communities. 2. A recent Habitat Conservation Plan, which provided conservation measures intended to protect multiple aquatic species of concern over a large area, established an important precedent for surrogate species in aquatic conservation pursuant to the US Endangered Species Act. 3. The Habitat Conservation Plan's application of federally threatened bull trout was evaluated as an umbrella species for westslope cutthroat trout, which is in decline but not listed under the Act. Approximately 75% of known westslope cutthroat trout strongholds are not captured within bull trout strongholds west of the continental divide. The Habitat Conservation Plan failed to evaluate the suitability of this umbrella species and consequently failed to cover important priority areas for westslope cutthroat trout conservation. 4. This case study highlights the feasibility and importance of formally validating assumptions of surrogate species utility in multi-species conservation planning.