Ecological Response to Human Activities in Southwestern Alberta: Scientific Assessment and Synthesis


D. Farr, A. Braid, A. Janz, B. Sarchuk, S. Slater, A. Sztaba, D. Barrett, G. Stenhouse, A. Morehouse, and M. Wheatley




This report summarizes the scientific evidence for ecological responses of soil, vegetation, hydrology, and wildlife to human activities in the Castle region of southwestern Alberta, based on over 150 peer-reviewed journal articles and technical reports.  While most of these studies were conducted elsewhere, many of their findings are relevant to the Castle region and biogeographically similar regions in Alberta.

While cattle grazing, forest harvesting, recreation, and other land uses have all impacted the region’s ecosystems to some degree, roads and trails are likely the most ecologically significant anthropogenic feature in the Castle region due to the increased human activities and impacts which they facilitate. For example, recreational use of off-highway vehicles (OHVs) along trails may affect water quality, stream flow, and fish habitat quality by increasing the rates of soil erosion and sediment input to aquatic ecosystems.  The loss of vegetation cover from OHV-related soil compaction and erosion may alter vegetation communities and facilitate the introduction and spread of invasive plant species. Human use of linear footprints has also been linked to increased grizzly bear mortality by increasing the likelihood of negative encounters between bears and people.

Evidence suggests that limiting or reducing land use and human activities in the Castle region would decrease vegetation disturbance, lower rates of invasive species infiltration and expansion, improve the condition of headwater streams, increase the viability of westslope cutthroat trout and bull trout populations, and reduce the risk of grizzly bear mortality. Further monitoring and research are required to reduce scientific uncertainty, understand the relative contribution of natural and anthropogenic drivers, and inform decision makers.