10 Reasons We Need to be Protecting and Restoring Wetlands in Canada

February 2nd is World Wetlands Day, celebrated internationally in commemoration of the signing of the Convention on Wetlands of International Importance in 1971 (1). World Wetlands Day celebrations raise awareness and recognition for the vital role that wetlands play in our world, both ecologically and socio-economically.

1. Wetlands provide natural resources, food and support for food systems

Wetlands provide food and essential habitat for many species of fish and shellfish, thereby supporting aquaculture and fisheries (2). In addition, wetlands provide the unique growing conditions required for various food products, such as cranberries and wild rice, which benefit from the wetland’s moist, nutrient rich soils (2, 3).

2. Wetlands prevent and mitigate flooding

When it rains, wetlands essentially act as a large sponge absorbing and storing rainwater. This storage becomes increasingly important during heavy rainfall events, when excess flood waters are retained by wetlands to slowly be released to receiving rivers and water bodies (4). The slow release of stormwater reduces peak flows in nearby rivers, which can prevent high flood waters and related damage. Studies have demonstrated that undisturbed wetlands can reduce flooding up to 29% in rural areas and up to 38% in urban areas, associated with flood damage cost reductions of $3.6 million and $51.1 million, respectively (5).

3. Wetlands protect against drought

The water storage capacity of wetlands allows them to maintain water sources during periods of drought. During periods of low rainfall, water stored in the wetland can slowly drain to underlying aquifers, replenishing groundwater sources, or to adjacent streams, maintaining minimum ecological stream flows (4, 6).

4. Wetlands provide essential habitat

Wetlands are considered one of the most productive ecosystems in the world, supporting a high level of biodiversity (7). Wetlands provide unique habitat to many species of birds, fish, mammals, reptiles and amphibians, who are attracted to the consistent water source and high level of productivity (8,9). Presently, a high proportion of North American endangered species or species-at-risk rely on wetland habitat for survival (10,11).

5. Wetlands purify our water

Storm runoff may contain high volumes of sediment, contaminants from urban runoff, or excess nutrients and pesticides from agricultural runoff (12). Wetlands provide a natural purification system for this contaminated water, encouraging sediment deposition by slowing down runoff and through biological removal of contaminants and nutrients by various wetland plant species (12, 13). The water treatment performance of wetlands has even been adapted for municipal and industrial wastewater treatment, in the form of artificial or constructed wetlands (13).

6. Wetlands provide coastal protection

Coastal wetlands, such as mangrove forests, seagrass beds and saltmarshes, prevent shoreline erosion and flooding of coastal areas (14). Wave energy is attenuated as water flows through these vegetated environments, reducing wave heights and thus erosive forces (14). The presence of vegetation also increases the shoreline’s water storage capacity, reducing flooding during high-water level coastal storms (15).

The shoreline protection capacity of coastal wetlands has great significance for developing coastal resilience in the context of a changing climate. Conventional coastal protection structures (e.g. seawalls, breakwaters) are projected to fail as sea levels rise and coastal storms intensify (16). Coastal wetlands, however, are self-repairing and are capable of adapting to rising sea levels through natural depositional processes (16, 17). Consequently, coastal wetlands have been identified as key nature-based solutions for climate change adaptation and future coastal resilience (16).

7. Wetlands are one of the most efficient carbon sinks

Wetlands sequester vast amounts of carbon, stored both in the living vegetation (above and below-ground) and the thick deposits of organic sediment (18). The wetland’s waterlogged soils suppress decomposition of carbon dioxide due to a lack of available oxygen (anoxic), creating anaerobic conditions (18). This allows layers of carbon-rich soils to be buried as new sediment accumulates on top. The carbon sequestration capacity and efficiency of wetlands rivals all other natural ecosystems, even forests (9,19).

In what is now Canada, peatlands (terrestrial organic wetlands) account for 59% of all organic carbon stored in Canadian soils – approximately 147 Gt (20). That stored carbon is 200-times Canada’s total annual greenhouse gas emissions (729 Mt CO2 eq in 2018) (21).

8. Wetland losses have been immense historically

Wetland environments are being degraded or destroyed faster than any other ecosystem on the planet, and it is estimated that more than 50% of wetlands have already been lost globally (6). Most wetland losses are associated with land conversion for agriculture or fragmentation due to urbanization (6). Intact wetlands continue to be degraded due to pollution, invasive species and altered hydrologic connections (6).

The greatest period of wetland loss in what is now known as Canada occurred between the 1800s and 1990, with a total estimated loss of 200,000 km2 (6). Estimates of wetland losses in the Prairies are between 40-71%, and in present-day southern Ontario, it is estimated that 72% of the 20,266 km2 of intact wetlands have been destroyed (6).

9. Wetland loss is predicted to increase in the context of climate change

Sea-level rise, changes in precipitation patterns, extended periods of drought, and increasing severity and frequency of wildfires are all consequences of global climate change that threaten the fate of wetlands (22).

10. One-quarter of the world’s remaining wetlands are found in present-day Canada

Present-day Canada hosts 1.5 million km2 of wetlands, making up 16% of the country’s total land mass and ¼ of the world’s remaining wetlands (6). Thirty-seven wetlands in Canada have been designated wetlands of international importance, with a total size of 131,000 km2 (6) – roughly the size of Nova Scotia, New Brunswick and PEI combined. Majority of the wetlands within present-day Canada are peatlands, mostly found in the boreal and subarctic regions (6). Approximately 60% of these peatlands are expected to be severely impacted by climate change, with significant carbon-balance implications (6, 23).

Considering the numerous benefits of wetland ecosystems, and particularly their significance for natural climate solutions and climate change adaptation, it is imperative that we act in support of wetland preservation and restoration. Furthermore, as stewards of the land upon which we live and rely, we must uphold our duty to protect the substantial portion of remaining global wetlands that are found within what is now Canada.

Happy World Wetlands Day!