The Development of a Structured Adaptive Approach to Klamath Basin Sucker Recovery Planning

Listed as endangered in 1988, the Lost River sucker (Deltistes luxatus) and Shortnose sucker (Chasmistes brevirostris) were once abundant and widely distributed in the Klamath Basin in Southern Oregon and Northern California. Populations of both species have been declining since the late 1960’s. Factors thought responsible for declines include naturally occurring disturbances (e.g., periodic drought), water resource and land development activities, degradation of habitat and water quality, and interactions with introduced exotic species. Effective recovery of Klamath sucker populations requires an integrated approach in assessing future population response to conservation strategies and natural variability over time and space. Quantitative decision analysis (QDA) provides a means for evaluating the effects of management strategies on Klamath Basin suckers and incorporating monitoring data to improve understanding of population dynamics and future conservation decisions. Utilizing QDA, we developed a prototype decision model to evaluate the relative effectiveness of alternative conservation actions. Sensitivity analyses of the prototype model indicated that model estimates were highly sensitive to uncertainties regarding sucker population dynamics, particularly during early life stages. To address these uncertainties, we propose an adaptive approach to sucker recovery that integrates monitoring, research, and management.