Wildfire and vegetation impacts on sediment transport and hillslope evolution in mountain landscapes

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Wildfire is a serious hazard in many parts of Canada, posing a particularly significant threat when fires spread to settlements and developed locations. Severe wildfires in recent years have highlighted the necessity for improved understanding of how wildfires initiate, spread and impact the environment. Despite the hazard they present to humans, wildfires are a natural form of disturbance and are a critical part of the environment; ecosystems and wildlife have adapted to and rely on wildfire occurrence. Wildfire suppression may not only increase the severity of future fires as fuels on the forest floor accumulate, but it disrupts natural ecosystem operation. Improved understanding of wildfire behaviour and post-fire effects on natural systems is required to ensure sound management strategies are adopted. Wildfires may lead to death of ground vegetation and/or trees, and may modify soil chemistry, thereby decreasing water infiltration into soils. As a consequence, modifications to water movement below and above the land surface, and in rivers, may occur. These changes may lead to increased soil erosion and/or landsliding, and thereby increase sediment loads in rivers. Such changes may adversely impact water quality and fish habitat. Increased landsliding rates also present a hazard to human settlements and infrastructure. In addition, strong connections exist between wildfire occurrence and climate change due to greenhouse warming, with the possibility of increased fire activity and severity in certain regions. The mission of this research is to better understand impacts of wildfire on natural system operation. This work considers post-fire erosion in the Canadian Rockies through field-based investigations. In addition, landscape response to future climate change and associated modifications to wildfire regimes is assessed using numerical modelling simulations. The research team undertaking this work will produce highly significant results, that will be valuable to the scientific community and to environmental managers considering post-fire erosion. Results will also provide baseline information about natural, post-fire erosional processes over longer times scales, and allow for strategic, long-term management of landscapes.