Land use, climate change and ecological responses in the Upper North Saskatchewan and Red Deer River Basins: A scientific assessment

 

Dan Farr, Colleen Mortimer, Faye Wyatt, Andrew Braid, Charlie Loewen, Craig Emmerton, Simon Slater

 

 

 

The Eastern Slopes of Canada’s Rocky Mountains have been managed for headwater protection, natural resource production, recreation, and other land uses for over a century. To support effective land use planning in the Upper North Saskatchewan and Upper Red Deer River Basins, key land use patterns and climate variability were summarized, and potential ecological responses to these stressors were reviewed. While knowledge of historical fire regimes is incomplete, wildfire suppression since the mid-20th century has likely decreased fire frequency in the study area. Because post-fire environments are relatively scarce, future fires represent opportunities to learn how the dynamics of water, wildlife, and other parts of the ecosystem are altered by fire. In addition, because forest harvesting in the study area has largely replaced wildfire as the dominant stand-replacing disturbance, further research is needed to better understand how ecological responses to forest harvesting differ from responses to fire. Forest harvesting and other anthropogenic disturbances are concentrated in the eastern part of the study area, where high densities of roads and trails may affect wildlife populations, facilitate invasive species, and alter stream water quality via increased sediment inputs. However, the response of wildlife and other ecosystem properties depends on the amount and type of human use along linear disturbances, which is not monitored in a comprehensive fashion in the study area. It is also difficult to separate the ecological effects of human activities from the effects of climate change, because monitoring designed to distinguish among those stressors is lacking. In contrast, streamflow has been monitored continuously for several decades, and preliminary analyses point to climate-induced shifts in the timing of peak flow throughout the study area. Enhanced monitoring of ecological responses to climate, land use and fire within study area watersheds would increase knowledge of how these stressors affect water quality, water quantity, and wildlife.