Beach-dune systems serve important ecological and geomorphic functions as specialized habitat and as a sedimentary ‘buffer’ against storm surges, coastal erosion, and sea-level rise. These systems are rare in western Canada and support a number of endangered species. Historically, dunes have been subject to intense stabilization efforts to reduce wind erosion and sand drift. However, dune stabilisation efforts reduce morphodynamic resilience and biodiversity. Recently, more dynamic dune restoration approaches have emerged that increase natural geomorphic processes (e.g., aeolian sand transport, dune mobility) to provide more resilient landscape and ecological conditions for native species.
A dynamic restoration project is underway with Pacific Rim National Park Reserve, who removed invasive marram (Ammophila spp.) grasses within a foredune-transgressive dune complex at Wickaninnish Beach near Uclulet, BC, to improve habitat conditions for the SARA-listed Pink Sand-verbena (Abronia umbellata).
Marram was introduced in the 1940s as conservation effort against coastal erosion and sand drift. Historical photos of the dunes since the 1970s show vegetation colonization, by both Ammophila and native species, is occurring rapidly and has reduced active sand surface by 28% (Heathfield & Walker, 2011). In turn, aeolian activity and the beach-dune sediment budget have been impacted considerably and have produced in less favourable ecological conditions for native and endangered dune plant species.
This project is highly novel as foredune restoration of this extent is limited in Canada. The research builds on established methods for quantifying sediment supply, volumetric change and geomorphic responses using field experiments, vantage photography and topographic surveying, and aerial LiDAR mapping. Results are informing ongoing restoration initiatives and land-use management by Parks Canada Agency.
This project is supported by Parks Canada Agency, MITACS Accelerate and Dr. Walker's ongoing NSERC Discovery Grant.
Heathfield, DK, Walker, IJ (2011). Analysis of coastal dune dynamics, shoreline position, and large woody debris at Wickaninnish Bay, Pacific Rim National Park, British Columbia. Canadian Journal of Earth Sciences, 48(7): 1185-1198.
Eamer, JBR, Darke, IB, Walker, IJ, (in revision). Geomorphic and sediment volume responses of a coastal dune complex to invasive vegetation removal: Wickaninnish Dunes, Pacific Rim National Park Reserve, British Columbia, Canada. Earth Surface Processes and Landforms.
Darke, IB, Eamer, JBR, Beauregard, H, Walker, IJ (in revision). Dynamic dune restoration at Pacific Rim National Park Reserve, British Columbia, Canada. Earth Surface Processes and Landforms.