Comparing Models and Spatial Scales to Determine Climate Change Effects to Threatened Lahontan Cutthroat Trout

Increasing acceptance of Global Climate Model (GCM) projections that the Earth’s climate will continue to warm well into the middle of the 21^st century has generated a plethora of climate change models for downscaling global forecasts to scales more relevant for managers.  The diversity of approaches and the spatial and temporal variability in the forecasts can be daunting for managers needing to make resource allocation decisions today for an uncertain future.  We use Lahontan cutthroat trout as a case study for the comparison of findings from three different assessments of climate change impacts on this threatened subspecies.  These include a coarse-scale assessment of environmental change assuming a westwide temperature increase of 3°C; an assessment of environmental change using mid-late century forecasts from a Regional Climate Model (RCM); and reach scale forecasts from multiple GCM’s linked to a macroscale hydrologic model.