Cover Story

Endangered Ecosystems: Wetlands

By Andrea Smith

Not far from Ottawa’s city limits I’m suddenly immersed in a landscape more typical of the subarctic or arctic regions of northern Canada. I’ve come to Mer Bleue Bog, a stunning example of boreal peatland named for its resemblance in foggy weather to a large blue sea. The 3,700-hectare sphagnum bog is among the largest in southern Ontario and has been designated an internationally significant wetland under the United Nations’ Ramsar Convention.

Mer Bleue forms part of the National Capital Commission’s Greenbelt system and contains a 1.2-kilometre boardwalk built to accommodate curious visitors like me. My family and I begin our explorations by crossing over a marshy area, filled with cattails, alders, willows and sedges. As we enter the bog proper, the familiar marsh habitat is soon replaced by a vast expanse of heath vegetation and stunted black spruce and tamarack forest. My four-year-old son thrills at the idea that this peat-covered wetland is as acidic as vinegar and home to mysteriously named plants such as heart-leaved tearthumb, prostrate sedge and sticky everlasting.

Like other bogs, Mer Bleue is characterized by poor drainage, leading to a high water table, low pH and a general lack of nutrients. These features, combined with the thick layer of sphagnum moss that insulates the bog from sun, makes Mer Bleue a particularly difficult place for species to thrive. Many of its plant species, such as Labrador tea, leatherleaf and larch, are thus more typical of boreal or tundra environments and are rare in this part of the province. Mer Bleue is also home to a variety of animals, including beaver, muskrat, mink, the endangered spotted turtle and the rare Fletcher’s dragonfly.

Wetlands, which include bogs, fens, marshes and swamps, are Ontario’s most diverse and productive ecosystems. They provide habitat for many types of plants and animals, including many species at risk such as bald eagle, Fowler’s toad, massasauga rattlesnake, orangespotted sunfish, American ginseng and prairie-fringed orchid. Wetlands also perform key ecological functions, such as purifying and storing water and protecting terrestrial habitat from storm damage, flooding and erosion. As well, wetlands are popular destinations for bird watchers, photographers, canoeists, hunters and anglers seeking recreational opportunities.

Yet despite their importance of wetlands, at least 70 percent of wetlands in southern Ontario have disappeared in the last 200 years, largely drained for agriculture or filled for development. Many of those that remain have been severely degraded by pollution, invasive species and artificial modification of water levels. No specific wetland legislation exists at either the federal or provincial level, although provincially significant wetlands do receive protection under the Provincial Policy Statement (PPS) in Ontario. Under the PPS, development is prohibited in provincially (but not locally or regionally) significant wetlands south and east of the Canadian Shield, but can occur in significant wetlands on the shield as long as it has no negative impacts on wetland features or their ecological functions. Furthermore, any development adjacent to significant wetlands anywhere in Ontario must not cause negative impacts.

Nevertheless, “there’s still development occurring in wetlands despite the PPS,” says Natalie Helferty, director of conservation policy at Ontario Nature. “We’re seeing a lapse in the upholding of the PPS in practice. We’ve lost almost all wetlands in southern Ontario, so everything in my

mind is significant to protect from a watershed management perspective,” Helferty argues. “If you keep degrading the quality of the wetlands, then nothing will be significant enough to protect.”

Climate change, combined with rising development pressures, is projected to increase the strain on wetlands even further. Potential effects on wetlands could include loss of breeding habitat for amphibians and waterfowl, a decline in flood-control capacity and increased erosion. “The province needs to take climate change impacts very, very seriously,” says Helferty. “The importance of wetlands is clearly overlooked by the province in its legislation and regulations so far.”

Back at Mer Bleue, we’re now in the midst of the open heath, surrounded by whimsically white-tufted cottongrass and fragrant Labrador tea. It’s hard to imagine such an impressive wetland disappearing, and thanks to the foresight of the Canadian government 50 years ago, this bog at least is protected. But Mer Bleue is by no means immune to threats to its ecological integrity. The exotic plant species purple loosestrife, glossy buckthorn and European frog-bit have already invaded the marshes of Mer Bleue, and people often dump used tires, refrigerators, building and construction waste and, occasionally, cars in the area. In addition, various adjacent land uses affect the quality and quantity of the wetland, including urban development, road building, drainage practices, farming and landfills.

By Lorraine Johnson