Nature’s Oases: Wetlands of the Land O’Lakes

Sep 02, 2010

By Steve Blight

Photo: Typical Ontario Marsh

A couple of weeks ago I was wandering about our property east of Sharbot Lake when I stopped at a rocky knoll overlooking a small wetland. This wetland is a former beaver pond abandoned by the beavers several years ago, which has since grown in with a host of wetland plants. Five or six butterfly species including fritillaries and monarchs were flitting from flower to flower in search of nectar. Against the sonic background of a million crickets and other late summer insects, a few song sparrows chipped and chirped as they foraged in the shrubs and other tall plants along the edges. Looking across the gently waving sea of flowering goldenrod, boneset and joe-pye weed, I reflected on the richness of this wetland and of wetlands in general.

Thanks to its Canadian Shield geography, the Land O’Lakes area is extremely rich in wetlands. The rocky ridges and glacial deposits have given rise to countless poorly drained depressions that fill up with water. Add in the numerous shallow lakes and streams, normally plentiful rain and snow and large local beaver population, and you have the perfect mix for a paradise for wetland lovers.

Wetlands come in all shapes and sizes. Ponds are typically well-defined basins, filled with stagnant water and fringed with vegetation. The shallow depth of a pond allows water lilies and other bottom-rooted plants to reach the surface. Marshes are wetlands typically dominated by cattails, coarse grasses, sedges and rushes. Abandoned beaver ponds often become marshes once the dams have broken down and most of the water gone. Swamps are forested wetlands that support tall trees, shrubs and a variety of low-growing plants. In our area swamps often support elms, silver and red maples, white cedars, yellow birches, alders, black ashes and other water-loving trees.

Bogs are poorly drained and nutrient-poor wetlands dominated by mosses, which decompose slowly to form peat. Peat bogs support a variety of fascinating plants adapted to an acidic environment including pitcher plants and sundews. These are both carnivorous plants that get most of their nutrients from insects they capture in ingenious ways. The Mer Bleue Bog in east-end Ottawa is a superb example of a typical northern peat bog that people can visit to learn more about bogs.

Fens are wetlands that resemble bogs, but with more nutrients available and water that is less acidic. A very well-known fen in our area is at the Purdon Conservation Area near Lanark Village. This wetland is noted for its fantastic late-June display of thousands of pink and white blooms of the showy lady’s slipper orchid – truly an awesome sight.

Wetlands play several very important ecological roles. They act like giant sponges, soaking up rain and snowmelt and slowly releasing water in drier seasons. I once witnessed this taking place on our property. After a heavy rainfall in later summer, a small stream was flowing nicely, delivering a steady volume of water into the abandoned beaver pond mentioned earlier. However, the outlet stream at the other end of the pond was bone dry, the wetland absorbing every drop of water flowing in.

Wetlands filter the waters of our lakes, rivers and streams, reducing pollution and protecting water quality. The vegetation in wetlands removes phosphates and other plant nutrients washed in from the surrounding soil, slowing the growth of algae and aquatic weeds in larger water bodies. This growth can be a serious problem where dead and decaying algae rob the deeper waters of their oxygen. Wetlands also reduce soil erosion by checking or slowing the runoff from storms and thaws.

Wetlands are the homes for a host of animals, meeting their essential breeding, nesting, nursery, and feeding needs. Without wetlands, some wildlife species would disappear. For example, wetlands are the whole world for many species of frogs, salamanders, snakes, turtles, and aquatic insects. Fish such as stickleback and pike come to marshes to spawn and feed in the shallow waters.

Among the smaller mammals living around wetlands are shrews, voles, muskrats and beavers as well as predators like mink and otters. More than 100 bird species inhabit or make use of Canada’s wetlands. Some birds, like the Swamp Sparrow and Marsh Wren, nest almost exclusively in marshes. Millions of ducks, geese, gulls, and other waterfowl also nest, breed, and feed there along with numerous waders and shorebirds including herons, bitterns, rails, and sandpipers.

Standing on that rocky outcrop, it made me glad to know that our little wetland was contributing to the natural richness that makes the Land O’Lakes such a special place.

Please feel free to report any observations to Lorraine Julien at This email address is being protected from spambots. You need JavaScript enabled to view it.  or Steve Blight at This email address is being protected from spambots. You need JavaScript enabled to view it.