Wetlands: How Marshes and Swamps Can Save the World

by Ty Fischer, Riparian Habitat Restoration Intern

Addressing an issue as complex and multifaceted as climate change is a daunting task. The scale of the problem is so large, the impacts are so profound, and the need to solve current problems versus the need to prevent future ones from appearing is a tough balance to strike.

This last reason is why it is so important to direct our attention towards environmental objectives that attack the climate change issue from multiple angles at once, thereby affording us time to effectively adapt to the changes that are happening while simultaneously mitigating future harm. One of the best examples of such an objective is the conservation of wetland ecosystems.

Wetlands, which include marshes, swamps, bogs, and any other area with high groundwater levels as a result of permanent or temporary flooding (Government of Canada, 2016), provide an incredible array of different ecosystem services and functions that are (and will remain in the future) critically important to the planet’s well-being. They soften the blow of flooding events, soaking up excess water like giant sponges before it has the chance to wreak havoc on human cities or on fragile ecosystems. Wetlands also improve water quality by filtering out excess nutrients and toxins from farm, road, and sewage runoff. They are the source of many of our essential resources including food, energy, and building materials (Government of Canada, 2016). Additionally, and perhaps most remarkably, wetlands are extremely effective at sequestering carbon captured from the atmosphere which serves as a buffer against future climatic changes (Mitsch et al., 2013).

A Great Egret rest on a fallen tree in a large wetland (Simon Lunn).

Furthermore, the structural diversity of wetlands (as evidenced by their characterization in the literature of 49 wetland forms and 72 wetland types) gives rise to a considerable amount of biodiversity (Wulder et al., 2018). These areas are essential for providing food and habitat for countless species of macroinvertebrates, fish, amphibians, reptiles, mammals, and notably, various species of shorebirds and waterfowl (Government of Canada, 2016). In fact, many of Canada’s most iconic species of birds heavily rely on these areas throughout their lives.

Such species include the Great Blue Heron (Ardea herodias), a majestic bird with gray-blue plumage, a craned neck, and a long yellow beak. Great Blue Heron frequent freshwater marshes across the country, using these areas for many important aspects of their lives including nesting and for foraging for small fish and mammals (COSEWIC, 2008).

There is also the Great Egret (Ardea alba), unmistakable in their elegance with their eye-catching snowy white plumage and jet-black legs. Though the population in Canada is significantly smaller than that of the Great Blue Heron, they can still often be spotted in small ponds, estuaries, and marshes. They use these areas for nesting and for feeding on fish, reptiles, amphibians, and various small invertebrates (Cornell Lab of Ornithology, 2019).

Last but not least, the Least Bittern (Ixobrychus exilis). If you are lucky, you can observe this small heron when in the southern parts of Ontario, Manitoba, Quebec, and in the Maritime provinces. Like Great Blue Heron and Great Egret, these birds prefer large, shallow marshes with emergent vegetation where they can breed and satisfy their diet of fish, snakes, amphibians, and large insects (COSEWIC, 2009).

A Least Bittern camouflages in its wetland environment (Simon Lunn).

Canada, which has 25% of the world’s wetlands lying within its borders (Ray et al., 2021), bears a responsibility to protect these ecosystems and the species they contain – especially considering how many have already been lost. Fifteen-percent of the original wetlands in Canada (Cole et al., 2022), and 70% of the original wetlands in Southern Ontario, have been converted to other land uses (North American Wetlands Conservation Council, 2003). Though rates of habitat loss have slowed, growing human populations are ramping up the pressure for further conversion of wetlands to accommodate more urban, agricultural, and recreational areas. The risks of such changes include the fragmentation or destruction of wetland habitats, reduced water quality from excess nutrients or toxins, an increasing prevalence of invasive species, and much more (COSEWIC, 2009).

Everyone has the capacity to help push back against these changes, though! One of the best ways to do so is by supporting organizations that conduct research on the species in wetland ecosystems, organize restoration projects and other stewardship initiatives, and advocate for policy makers to create and enforce stricter regulations on land development. Watersheds Canada, Ducks Unlimited, Canadian Wildlife Federation, World Wildlife Fund Canada, and the Nature Conservancy of Canada are a few of Canada’s national authorities that are leaders in freshwater habitat conservation.

By working together, we can ensure these areas of significant ecological, hydrological, and anthropogenic importance remain in the forefront of our conservation priorities – for us, for our native species, and for the betterment of our collective future.


COSEWIC (2008). COSEWIC assessment and update status report on the Great Blue Heron fannini subspecies Ardea herodias fannini in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vii + 39 pp. www.sararegistry.gc.ca/status/status_e.cfm.
COSEWIC (2009). COSEWIC assessment and update status report on the Least Bittern Ixobrychus exilis in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 36 pp. www.sararegistry.gc.ca/status/status_e.cfm)
Environment Canada. (2016, January 14). Water Sources: Wetlands. Government of Canada. https://www.canada.ca/en/environment-climate-change/services/water-overview/sources/wetlands.html
Great Egret Overview, all about birds, Cornell Lab of Ornithology. Overview, All About Birds, Cornell Lab of Ornithology. (n.d.). https://www.allaboutbirds.org/guide/Great_Egret/
Mitsch, W. J., Bernal, B., Nahlik, A. M., Mander, Ü., Zhang, L., Anderson, C. J., Jørgensen, S. E., & Brix, H. (2012). Wetlands, carbon, and climate change. Landscape Ecology28(4), 583–597. https://doi.org/10.1007/s10980-012-9758-8
North American Wetlands Conservation Council (Canada) (2003). Wetland Stewardship in Canada: Contributed Papers from the Conference on Canadian Wetlands Stewardship. https://nawcc.wetlandnetwork.ca/Rep03-2e.pdf
Ray, J. C., Grimm, J., & Olive, A. (2021). The Biodiversity Crisis in Canada: Failures and challenges of federal and sub-national strategic and legal frameworks. FACETS, 6, 1044–1068. https://doi.org/10.1139/facets-2020-0075
Wulder, M., Li, Z., Campbell, E., White, J., Hobart, G., Hermosilla, T., & Coops, N. (2018). A national assessment of wetland status and trends for Canada’s forested ecosystems using 33 years of Earth Observation Satellite Data. Remote Sensing10(10), 1623. https://doi.org/10.3390/rs10101623