Large Scale Assessments : Lessons learned for Native Trout Management

-Large-scale assessments are useful tools for identifying population status of trout and other species throughout their ranges. We reviewed published and unpublished assessments for 15 native inland trout species in the United States to (1) evaluate common elements; (2) estimate lost habitat for native trout and (3) identify effective approaches or actions taken after completion of assessments to sustain native trout. Land use changes, loss of riparian vegetation, fragmentation of landscapes, poor land management practices, and presence of non-native fishes were the most common perturbations associated with the loss of native trout. We conservatively estimate that over half of the streams in the United States that historically supported native trout no longer do so. Many extirpated habitats may be hard to restore because of the difficulty of reversing land use changes or removing non-native fishes. Many extirpations occurred in the first 150 years after pioneer settlement but additional losses continue today. While many assessments have been effective at educating environmental professionals, most have had little influence in changing land use or realigning budgets for preservation or restoration. As human population growth and demands for natural resources increase, threats to native trout will likely increase resulting in further declines and extirpations.