|Grassy Narrows Marsh
What Is a Marsh?
Hecla's Managed Marsh
Wildlife Viewing Tips
Safety and Comfort
Wildlife Checklist Other Marshes
Named after the narrows, a channel between Hecla Island and the mainland, this is one of Manitoba's finest marshes and a major feature of Hecla/Grindstone Provincial Park.
Grassy Narrows and other marshes around Lake Winnipeg have been adversely affected by hydro-electric developments. Regulation of water levels to produce electricity downstream along the Nelson River has disrupted natural wet-dry fluctuations that are characteristic of marshes. Ducks Unlimited and Manitoba Conservation have developed a system of dykes to control water levels in this marsh and restore optimum habitat conditions.
This marsh is an important nesting area for Canada geese and a great variety of other waterfowl. Hikers and cyclists can travel the dykes to explore the marsh's wondrous beauty.
The plants and wildlife are parts of their living homes. Please respect them.
A marsh is a treeless lowland area of open water and vegetation, that usually has a greater variety of animals and plants than do lakes, grasslands or forests. It is the most productive biological community in Canada. Around the world, marshes are second only to tropical rainforests in productivity. In the short growing season at this latitude, marsh vegetation is more efficient at energy capture and storage than any other plant community.
Marshes have characteristic plants which grow in distinct zones or layers. The high canopy of emergent plants like cattails and phragmites occupies the tallest layer. On the water surface are duckweeds, the world's smallest floating plants, which are a rich source of protein for waterfowl. Microscopic algae abound throughout the area between the water surface and the soil base. Algae form the food base for tiny grazing animals, tadpoles, caddisflies, and snails. Submerged plants, which form the basic food for ducks, are rooted to the bottom of the marsh. Transparency of the water is most important, as clear water is essential for photosynthesis to occur. In turbid parts of Hecla's marshes, light cannot penetrate the water and these sites are too sterile for many submerged plants and animals to thrive.
In marshes there is a constant interplay between oxygen and carbon dioxide, as these two substances are passed back and forth between plants and animals, and their environment. All green plants manufacture food and are eaten by herbivorous animals such as mayflies and small crustaceans. Carnivorous animals, including dragonfly nymphs and fish, in turn eat these animals. Eventually all plants and animals die and decompose. Their basic components are then reabsorbed by plants and the whole cycle of life in the marsh begins again. There is a loss of energy and mass through gases, such as methane, produced during decomposition.
The re-routing of the causeway road in 1977 separated this portion of the marsh from Lake Winnipeg. To maintain good marsh habitat, water levels are being controlled:
A thriving marsh has equal areas of water and vegetation which are maintained by periodic flooding and drought. Flooding drowns plants and establishes open water. Drought exposes bottom debris to air and sunlight allowing faster nutrient recycling and germination of seeds to re-establish emergent vegetation. Natural marshes are constantly changing, but will eventually become dry land.
Nesting islands have been constructed to provide upland nesting sites and reduce the effects of predators on waterfowl. Ducks Unlimited and Parks and Natural Areas Branch are managing this part of Grassy Narrows Marsh for the benefit of wildlife and for the enjoyment and education of park visitors.
Look for these mammals or signs of their presence.
Reptiles and Amphibians
Try identifying these common marsh bird species.
Marshes are considered "endangered spaces" in central North America.
Grassy Narrows is one of several significant marshes in Manitoba which are readily accessible. Plan to visit at least one of these others in the near future.