Perched on the edge of your sea

As ocean tides sweep in daily from offshore, they carry silt and other materials that settle among the vegetation in the salt marsh environments on Canada’s coasts. The ecosystems that form, clinging to the shore, are part of the verdant beauty that draws us to the water’s edge.

These lush habitats are lively with birds, such as black ducks and herons, and provide nursery habitat for young marine wildlife—such as salmon in Pacific marshes and lobsters in Atlantic marshes. They buffer coastlines from erosion and flooding, and help maintain water quality for swimming, fishing and watersports.

But these ecosystems are being edged out.

Life on the edge

Canada’s coastal communities are growing. It may surprise you to learn that Canada’s overall coastal populations reached 5.5 million people in 2021, a notable increase of 5.3 per cent over the previous five years. More than three million of those residents are on the Pacific Coast and there are more than two million coastal inhabitants in Atlantic Canada.

As these communities grow, so too do the pressures on shorelines. But it can be difficult to accurately track the effects of the changes due to limited data on coastal ecosystems. As of 2022, salt marshes were mapped across 3,602 square kilometres of coastline in the Arctic, Pacific and Atlantic regions but large sections of coastline are not yet classified.

• What is a salt marsh?

Looking ahead, today’s salt marsh extent is in peril from all directions. Buildings, roads and other infrastructure nip away at salt marshes from inland while sea-level rise is sneaking up on the other side. Not only do they need room to exist, but coastal ecosystems need room to grow.

Gaining an edge

To date, the known extent of salt marsh ecosystems is an estimated 9 per cent of Canada’s coastline. As salt marshes shrink, so will their ability to support wildlife and shelter communities from storm surges and shoreline erosion. The good news is that the evidence of coastline losses and their mounting impacts is inspiring Canadians to protect coastal land.

In Yarmouth, Nova Scotia, DUC is stewarding more than 40 hectares of salt marsh and surrounding uplands that is close to Arcadia Salt Marsh, a Treasured Wetland of Nova Scotia. In nearby Argyle Head, DUC has also acquired nearly 1,830 metres of ocean frontage, an agreement that originally included six separate land parcels. Acquisitions like these require the dedicated commitment of multiple partners which included the Government of Canada and American-partnered support enabled by the North American Wetlands Conservation Act.

Remnant salt marshes have also been secured by donation. For example, in Nova Scotia, a donation of salt marsh preserves habitat in the Allains River Marsh near Fort Anne National Historic Park in the Annapolis Valley. In New Brunswick, DUC is the caretaker of a section of natural coastline donated by the Anglican Parish of Shediac in Pointe-du-Chêne, a busy holiday community in New Brunswick. Another rare seaside parcel on a highly developed coastline near Village-des-Poirier was donated by the Jean family on the Acadian Peninsula.

Marsh restoration techniques are also vital to coastline protection. In places like Jijuktu’kwejk Marsh and Fullerton’s Marsh, DUC has worked to restore salt marsh ecosystems with managed breaches of weakened dike systems that allow the habitat to flourish once again.

Every marsh counts. But larger-scale conservation policies are needed to slow—and reverse—the tide of loss.

Leading-edge policy

Canada is creating a foundation for better environmental policy. There is an emerging global emphasis on valuing ecosystems using both environmental and economic metrics, which policymakers can compare with other economic “accounts”. The federal government has created Statistics Canada’s Census of Environment for this purpose.

Alarm about coastline health, coupled with negative climate and biodiversity impacts, has put salt marsh ecosystems high on the priority list for this new type of accounting. DUC supported the development of the technical framework for valuing salt marsh ecosystems with peer-review expertise. This framework will establish baselines for the “extent, condition and services” of salt marshes—and help convey the urgency of investing in their protection. The success of ecosystem valuations will depend on the willingness of coastal communities to enact and enforce effective policies.

A firm ecological foundation for future decisions can be strengthened by widespread coastal mapping. Flood mapping is especially important for local governments so they can preserve environmental health while managing development along shorelines. This knowledge can protect salt marsh ecosystems, but it can also protect builders from high-risk areas prone to floods—either today or in the future as sea-levels rise.

The escalating waves of environmental challenges to Canada’s coastal ecosystem health are daunting. But each step towards conserving, mapping and protecting salt marshes is a step away from the edge of unsustainable coastal management. We need marsh environments to keep our coasts both safe and beautiful.