Cutthroat trout (CT; Oncorhynchus clarki ssp.) are extremely imperiled owing to a variety of stressors. Changing climate is adding to these stressors that have already relegated CT in the Southern Rocky Mountains to less than 35% of their native habitat. The Rio Grande CT (O. c. virginalis) occupies 12% of its native range and is currently under review for ESA listing as federally threatened. Changing thermal regimes, hydroclimate, and disturbance regimes will continue to alter the remaining habitat of Rio Grande CT. An understanding the status and trends of Rio Grande CT thermal habitats and the vulnerability of these habitats to climate driven changes in temperature and stochastic disturbance regimes would enable managers to develop more informed, climate-smart conservation strategies for Rio Grande CT populations.
Asses the vulnerabilities of Rio Grande CT habitats to climate driven changes in water temperature and stochastic disturbance events (i.e., drought, stream drying/freezing, wildfire, and debris flows) and create a model of Rio Grande CT population persistence.Complete a stream temperature model and modified Bayesian Network model for occupied Rio Grande CT streams. Those models will be integrated with a new analysis of spatially-explicit threats from extreme events (drought and wildfire) for Rio Grande CT populations using historical data compiled by the South Central Climate Science Center and predictions of vegetative changes from a Southern Rockies LCC study of the Rio Grande drainage (Friggens 2013). The approach used to identify climate change refuge habitats involves a combination of modeling and focused field data collection. The overall approach is to first create predictive, spatially-explicit models of thermal habitat conditions using existing continuous water temperature data and various abiotic covariates (e.g., geomorphology, air temperature, stream flow). The next step is to use (if it exists) or to create a model of CT population persistence.
Host meetings of Rio Grande CT working groups to finalize the analysis of climate change threats to extant Rio Grande populations and use this analysis to identify locations of potential refuge habitat for Rio Grande CT.Develop integrated range-wide conservation strategies by examining how Rio Grande CT refuge habitats relate to historical records of drought and wildfire for New Mexico habitats. This will include determining if changes in forest types may further exacerbate or buffer the threat of extreme events for Rio Grande CT habitat covered in the Friggens (2013) project.