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. Detection of any substantial adult recruitment for the last few decades has been minimal. We used a quantitative decision modeling approach to explore potential outcomes of alternative conservation strategies that include captive propagation and catch, grow, and release. Uncertainty about the factors responsible for the apparent lack of recruitment was represented using alternative models of system dynamics. Sensitivity analysis indicated that the model predictions were highly sensitive to population dynamics during early life stages and the alternative ideas of system dynamics. To address these uncertainties, I propose an adaptive approach to sucker recovery that integrates monitoring, research, and management.