Conservator

It’s high time to prepare for higher tides

Surf’s up, and we’re down, preparing coastal tidal marshes and communities for upcoming sea change.

By Janine Massey November 12, 2024

Strong ocean waves strike at the shore along Spanish Banks Beach during a late fall storm in Vancouver, B.C. Nearly a half million Canadians live within five metres of sea level, in communities at risk from extreme weather.

Coastal living appeals to the senses. The soothing sounds of waves and sea birds, the smell of fresh air, the picturesque scenery, and of course, the fresh seafood. It’s not surprising to learn that more than 3.2 million Canadians reside within 10 kilometres of the Pacific Coast and more than 2.2 million reside within the same distance of the Atlantic Coast, according to Statistics Canada.

Unfortunately, nearly a half a million of these Canadians live within five metres of the current sea level in communities that are at risk from extreme weather events.

Salt marshes: The solution is natural

Coastal birders, anglers and waterfowlers alike know that salt marshes or “tidal marshes” are rich with wildlife. They serve as nature’s nursery for young marine wildlife, including iconic species like salmon and lobster. These marshes are also highly effective climate solutions. They have a tremendous capacity to accumulate and store carbon and other greenhouse gases. They help protect our seaside communities, providing a buffer from coastal erosion, storm surges and flooding.

These tidal wetlands are typically found in the upper intertidal zone between mean sea level and high tide, where vegetation that is salt- and flood-tolerant can grow. The resilient organisms that live in tidal marshes cope with extreme variations in salt, oxygen and temperature levels; wave and wind action; and seasonal challenges including ice formations. Salt marshes cover an estimated nine per cent of Canada’s coastline, or 3,602 square kilometres in area. However, there are significant stretches of Canada’s coastline that are not yet mapped — a challenge that Ducks Unlimited Canada (DUC) is eager to help resolve.

Salt marshes are stabilized by plant roots, which bind sediment and soil forming a sturdy mass on the marsh floor. When these plants are lost, sediment and soil can easily erode and be displaced, leading to marsh recession that results in loss of native vegetation, carbon release and loss of feeding and breeding grounds for numerous species of birds, fish and other wildlife. Infrastructure such as dikes, causeways and commercial, industrial or residential developments can interfere with the health of these ecosystems, as can invasive species and severe weather events. Addressing this complex conservation challenge requires a multi-pronged solution, and our approach to conserving and restoring tidal marshes embodies just that.

Five ways that Ducks Unlimited Canada is helping our coastal salt marshes

1. Innovative research at Sturgeon Bank: Piloting new tidal marsh restoration techniques

Ducks Unlimited Canada uses a temporary sediment delivery pipeline to pump dredged sediment from the Fraser River onto the southern Lulu Island foreshore. © Fernando Lessa

The Fraser River Estuary in British Columbia serves as crucial habitat for hundreds of millions of out-migrating juvenile salmon that rely on these brackish ecosystems as they transition to the ocean. Essential to the B.C. economy and Indigenous ways of life, Fraser River Chinook salmon are also the primary prey of the endangered Southern Resident Killer Whales. Together with Boundary Bay, the estuary is also the most important overwintering area for waterfowl in Canada.

Research shows that since the 1980s, approximately 395 acres (160 hectares) of tidal marsh have died off at Sturgeon Bank. To address this large-scale loss, Ducks Unlimited Canada is leading a pilot project that tests and evaluates a localized, customized approach. Annually, approximately 1.6 million cubic metres of sediment dredged from the Fraser River are disposed of at sea rather than being reused for habitat restoration projects. The Ducks Unlimited Canada team, in partnership with Raincoast Conservation Foundation, Asarum Ecological Consulting, and the Lower Fraser Fisheries Alliance, uses a temporary sediment delivery pipeline to incrementally pump dredged sediment from the Fraser River onto the south foreshore of Lulu Island within the Sturgeon Bank Wildlife Management Area. This effort is part of a four-year pilot project, of which three years have already been completed. This new sediment layer is designed to provide a foundation that supports vertical marsh growth, helping to offset the impacts of rising sea levels on both the ecosystems and communities.

By restoring degraded tidal marsh, Ducks Unlimited Canada anticipates that this project will also help to protect the adjacent community of Richmond from coastal flooding as sea levels rise. This pilot project represents a “win-win-win” opportunity to beneficially re-use dredged sediment to support ecological resilience and coastal flood protection. The design and lessons learned from this pilot project may be applied to other areas of the Fraser River Delta and other estuaries throughout B.C.

2. Leveraging industry partnerships: The Nature Force

Staff from Nature Force partner organizations take part in tree-planting at a Ducks Unlimited Canada wetland restoration project in southern Ontario. © Ducks Unlimited Canada

Ducks Unlimited Canada’s delivery of the Sturgeon Banks Sediment Enhancement Pilot Project is one of many projects made possible in part through funding support from the Nature Force initiative, in partnership with 17 leading property and casualty insurance organizations in Canada. This innovative initiative aims to lead by example, showcasing the importance of proactive investment in nature-based solutions to enhance climate resilience in our communities.

A lot is at stake as floods represent the most common and costliest natural hazard in Canada. Over the course of this decade, the average cost of severe weather claims is expected to grow by 138 percent to $5 billion per year according to the Insurance Institute of Canada’s (IIC) 2020 report. In the summer of 2024 alone, Canadians experienced a record-shattering $7 billion in insured losses from extreme weather events, as reported by the Insurance Bureau of Canada.

The initiative has also placed an emphasis on education and experience, with partners bringing employees out to the field to see the projects and learn firsthand about the benefits of the work to downstream communities.

3. Using community science to fight Spartina: An invasive species threatening British Columbia’s salt marshes

Conservation teams identify and document Spartina colonies, enabling rapid response and effective management efforts through real-time mapping technology © Ducks Unlimited Canada

The picturesque and productive estuaries of coastal B.C. are threatened by a silent invasion — a cordgrass known as Spartina. Native to parts of Europe and the east coast of North America, this salt-marsh-dwelling plant was discovered in B.C. mudflats in the early 2000s and began quietly transforming local ecosystems, overpowering local plant species and degrading ecosystem functions and wildlife habitat. With funding from the federal and B.C. governments and the Port of Vancouver, Ducks Unlimited Canada joined forces with the B.C. Conservation Foundation in recent years to develop an app designed to map and classify the invasive plant. The app, developed using software from the Environmental Systems Research Institute (ESRI) and relying on geographic information system (GIS) technology, allows conservation staff to document and report the size and location of Spartina plants in real time. Armed with their smartphones and the power of technology, invasive plant surveyors can quickly identify Spartina colonies, allowing for rapid response to the threats the plants impose, which includes displacing native plant species, leading to a reduction in biodiversity and changes in ecosystem functions that contribute to flood risks. Additionally, the dense growth of Spartina can create monocultures that limit access for wildlife, including waterfowl and shorebirds, to essential food sources like benthic invertebrates and biofilms, which are critical during their migratory periods.

The app has revolutionized the battle against Spartina. Real-time data has poured in, enabling conservationists to track populations, measure progress and mobilize resources more effectively. Once locations are known, volunteers and conservation staff physically eliminate the invasive grasses using methods that, depending on the Spartina species, may include manual removal, and more recently, the application of a low-concentration herbicide mixture dispersed through direct application methods using spray wands, which minimizes the effects of the mixture on neighbouring native plants. This method is proven to be very effective in battling Spartina growth and spread. Once the invasive grasses are removed, restoration of the coastline through the addition of native plants is completed where necessary, though often these native plants retake the landscape all on their own.

4. Conserving the Chignecto Isthmus: The race to shore up an Atlantic shoreline

Salt marshes in the Chignecto Isthmus, a narrow, low-lying region that connects Nova Scotia and New Brunswick, help protect a vital transportation and trade corridor. © Ducks Unlimited Canada

As the severity and frequency of weather events increases, Canada has a narrow window to proactively invest in our most at-risk areas and there are few areas more vulnerable to climate change than the land bridge connecting New Brunswick and Nova Scotia. As the only road and rail connection between the provinces, it is a vital transportation corridor with an estimated 50 million vehicles and $20 billion in trade crossing this land bridge each year. It is also home to communities and agricultural production.

The Chignecto Isthmus contains some of our most productive ecosystems, including salt marshes that trap and store carbon, mitigate against floods and sea-level rise, prevent erosion, filter water and provide vital wildlife habitat. Unfortunately, over 60 per cent of the area’s wetlands have already been lost to development.

As Canada’s leader in wetland conservation and restoration, Ducks Unlimited Canada is already very active in this corridor with over 200 projects representing 20,000 acres (8,000 hectares) and leverages funds from all levels of government, industry, partner organizations and individual supporters to complete this vital work. It will take a “whole of community” approach to conserve and restore this region’s vital salt marsh habitats and give the land bridge a fighting chance against extreme weather events and sea-level rise.

5. Using technology to map our wetlands: Taking stock of our precious resources

What gets measured, gets managed. Mapping our tidal wetlands is an important step towards prioritizing their conservation and restoration. Maps can help classify ecosystems and convey data measurements of soil moisture, hydrodynamics, carbon density, nutrient levels and more. They can also help us to monitor ongoing conservation progress.

Advancements in technology have dramatically improved every aspect of mapping. In fact, the costs per kilometre of procuring and analyzing the data have come down by about 75 per cent, thanks to remote-sensing tools like drones and the processing power of machine learning software like object-based image analysis. This, combined with reduced costs of data storage have made scalability and repeatability of mapping a reality.

Sea-level rise

Sea level rise is a real and imminent threat to our nation’s coasts. Our conservation work can help.

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