What's a fen? What's a bog?
Discover four different types of wetlands found in Ontario and why they're important
Minden-area wildlife biologist Paul Heaven takes a look at the shoreline of a Provincially Significant Wetland near Harcourt, Ont., in the Haliburton Highlands. The Elephant Lake complex, which includes parts of the York River and Baptiste Lake, is one of only two Provincially Significant Wetlands in the Highlands. It's a wild, beautiful place with several different kinds of wetlands located within the complex.
With files from the Federation of Ontario Naturalists' Family Nature Notes
and Wildlife Biologist Paul Heaven
Photos supplied by Paul Heaven
WHERE CAN YOU FIND insect-eating plants, fish-eating insects, one of the world's smallest flowering plants and Canada's most industrious mammal?
Wetlands!
Wetlands are found on every continent except Antarctica and in every climate from the tropics to the tundra. Many of the wetlands found in Ontario were created between 10,000 and 14,000 years ago at the end of the last Ice Age.
Retreating glaciers scraped the ground creating large depressions in the land. As the glacial ice melted, water filled these hollows and, in some areas, wetlands were created. Before the settlers arrived, wetlands covered more than half of Ontario. Today, less than a quarter of these wetlands remain.
A wetland is exactly that, wet land. It is an area that has standing water at or near the surface for most of the year. These ecosystems (a community of organisms and the environment in which they live and interact) do not have to be continuously wet; many are wet only in the spring after the snow melts. Wetlands may be located along shorelines and riverbanks but are often found in isolated depressions or hollows.
Because soils of wetland ecosystems are often water-saturated, there is little or no oxygen in the soil pores (the spaces between soil particles). Wetland plants are specially adapted to anaerobic (low oxygen) conditions. Some wetland plants such as the white water lily have developed hollowed stems in order to allow the leaves to float on the surface of the water to take oxygen from the air.
Four unique types of wetlands are found in Ontario.
Which description best fits the wetland in your neighbourhood?
1. MARSHES are found along the shores of rivers and streams and in the shallows of ponds, lakes and sea coasts. They support a variety of floating and emergent plants (plants that are rooted in the soil and grow out of the water such as Cattails and Arrowheads).
Marsh characteristics include:
* periodically or permanently covered with water;
* commonly created by beaver activity
*dominated by emergent plants such as Cattails, rushes and grasses with floating-leaved plants such as Water Lilies or submerged plants such as Coontail.
Plants and animals that might be found in a marsh include: Red-winged Blackbird, Virginia Rail, Raccoon, Muskrat, Water Snake, Bullfrog, Northern Pike, Sunfish, Dragonfly (adult), Dragonfly (nymph), Cattail, Water Lily, Arrowhead, Newt and Coontail.
2. SWAMPS are treed wetlands and may be isolated or found along rivers, streams and lakes. They are often formed due to flooding after spring snow melt. Trees such as White Cedar and Balsam Poplar and shrubs like the Lowland Pussy Willow can be found in swamps.
Swamp characteristics include:
* 25% cover of trees or 50% cover of tall shrubs
* flooded either seasonally or for long periods of time;
* often flooded in spring, but may be quite dry in summer;
*typical trees found in swamps include Silver Maple, Black Ash, Black Spruce, White Cedar and Tamarack, or tall shrubs such as Willow, Alder and Dogwood.
Plants and animals that might be found in a swamp include: Great Horned Owl, Wood Duck, Pileated Woodpecker, Mosquito, Mink, Garter Snake, Wood Frog, Marsh Marigold and Sensitive Fern.
3. BOGS are hummocky wetlands commonly found in northern parts of the province. They are located in deep, bowl-like depressions and are filled with layers of peat (slowly decaying plant material). There is no drainage to let water escape from bogs so they are usually filled with stagnant water. Sphagnum moss, trees such as Black Spruce, and shrubs grow on this spongy base. Bogs are acidic.
Bog characteristics include:
* peat-filled depressions that receive little surface runoff or ground water from the surrounding soils;
* surface waters are acidic and low in mineral nutrients;
* usually covered with a carpet of Sphagnum mosses, some sedges and shrubs;
* also found are unusual insect-eating plants such as Sundew, Pitcher plant and Bladderwort;
* bogs are rare in southern Ontario.
Plants and animals that you might find in a bog include: White-throated Sparrow, Ring-necked Duck, Spotted Turtle, Red-backed Vole, Round-leaved Sundew, Swamp Blueberry, Labrador Tea, Black Spruce, Large Cranberry Black Spruce, Mountain Holly, Sheep Laurel, Bog Laurel, Cottongrass.
4. FENS, like bogs, are usually located in low-lying areas of northern Ontario. Water slowly flows in and out of these sedge dominated wetlands. A diverse community of sedges, rushes, grasses, low shrubs such Sweet gale and insect-eating plants such as Sundew live in fens. Fens may dry up completely in warm summer months.
Fen characteristics include:
* peatlands located in areas where ground water discharges to the surface;
* vegetation usually consists of sedges, some mosses, grasses, reeds and shrubs;
* unusual insect-eating plants such as Sundew, Pitcher Plant and Bladderwort are found in nutrient-poor fens;
* fens are not common in southern Ontario.
Plants and animals that might be found in a fen include: Northern Harrier, Yellow Warbler, Meadow Vole, Snowshoe Hare, Mink Frog, Water Beetle, Damselfly, Sedge, Bog Rosemary, Bog Willow, Buckbean, Flat-leaved Bladderwort, Pitcher Plant, Shrubby Cinquefoil, Showy Lady's Slipper and Grass-of-Parnassus.
Why are wetlands important?
*Wetlands provide habitat (food, water, shelter and space) for fish, birds, wildlife and insects, including more than one-third of the threatened and endangered species in North America.
*Wetlands act like giant sponges holding large quantities of water and reducing floods.
*Wetlands release their stored water slowly ensuring a steady supply of water for many communities.
*Wetlands are areas of groundwater recharge and discharge
* These ecosystems act like giant filters, trapping sediment and pollutants that are washed off the land. Wetlands help improve water quality in areas where pesticides and fertilizers are used.
*Wetlands along rivers, lakes, streams and the sea coast help control erosion.
*Historically, these ecosystems supplied food and resources to native people and early settlers. Today people still use wetlands to grow wild rice and cranberries.
*Wetlands are beautiful, natural areas that allow people to enjoy an amazing variety of wildlife in their natural habitats.
Some examples of wetland plants include cattails, water horsetail, arrowheads, water lilies, sundew, mosses and ferns. Sundews are small bog plants that eat insects. The sundew leaves have long hairs with sticky tips. Once an insect is stuck to the hair the leaves fold over to trap the victim and it is eventually digested.
Some examples of insects found in wetlands include stoneflies, water striders, water boatmen, predaceous diving beetles, caddisfly larvae, damselflies, dragonflies, whirligig beetles, mosquito larvae, water tigers (diving beetle larvae) and dragonfly nymphs.
Threats to Wetlands
In the past, wetlands were drained, dredged and filled to create fertile crop land. Today, wetlands still are being destroyed to expand agricultural land, for building developments, cottages and road construction.
Peat harvesting destroys many bogs and fens. Peat is harvested and used as a fuel source, for improving soils in gardens (also known as peat moss) and as an absorbent material in products such as diapers. Because it often takes 100 years for a depth of 2.5 cm of peat to form in a wetland, it is considered to be a non-renewable resource just like coal, oil or natural gas.
The invasion of non-native species such as Eurasian water milfoil, phragmites and purple loosestrife threatens the health of our wetlands.
The natural reversible changes in wetlands may be almost insignificant compared to the disruption caused by human interference. Draining or filling in wetlands permanently destroys entire communities of plants and wildlife. Burning off or cutting down surrounding weeds, brush or other vegetation eliminates, at least temporarily, vital nesting places and escape cover. Building a highway through a coastal marsh or erecting a small dock at the marshy edge of a lake where you moor your rowboat is also damaging.
Air and water pollution are serious problems. Insecticides, weed killers and industrial wastes take a heavy toll on plants, fish and other wildlife.
This destruction is happening all across the country, as industry, commerce, agriculture and our appetite for "the good life" continue to swallow up our wetlands.
For more information about wetlands, go to:
Working Around Wetlands
Wetlands of Ontario
Wetkit: tools for working with wetlands
The Ramsar Convention on Wetlands
Wetland Watch
Wetland Habitat Fund
For more information about Paul Heaven:
Glenside Ecological Services Limited
To read EH's comments on Elephant Lake's Site Evaluation Report, click here.
To see the letter EH! sent to the Minister of Municipal Affairs,
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The cultural heritage of wetlands
The history of wetlands and people
One of the 13 "bundle burials" excavated from the southwestern shore
of the Gulf of Nicoya, Costa Rica. (Photo: Museo Nacional, Costa Rica,
on the Ramsar web site)
"Wetlands of great antiquity, as well as those of recent times, contain the evidence of their own history, and preserve testimony of human activity."
From The Ramsar Bureau, Switzerland
The relationships between wetlands and people are many, varied, and frequently very close. Many of today's important wetlands are of great antiquity and may show clear signs of early human uses, whilst even areas now dry may have been wetlands in remote times and may still preserve significant evidence of the human past.
Along the African Rift Valley, former lakeshore wetlands have preserved early hominid sites such as those in the Olduvai Gorge, which may be 2 million years old or more. In the bed of the River Jordan, at Gesher Benot Ya'aquov in northern Israel, the extraordinary persistence of wetland conditions has led to the survival of evidence for human activity in the valley from 800,000 years ago. Animal bones, stone tools and a great diversity of plant remains indicate that people came to the valley wetlands to hunt or scavenge, and that they used wetland vegetation for food and raw materials.
Many wetlands in temperate and sub-arctic zones, on the other hand, came into being only about 12,000 years ago, when the glaciers of the last Ice Age began to melt and sea levels rose. Other wetlands may even owe their presence to human activity. We know from archaeological and documentary evidence that the Norfolk Broads of eastern England are the result of peat-cutting 500-700 years ago and, in many places over the last 200 years, gravel extraction on floodplains has been followed by the appearance of lakes and marshes.
This close relationship between earlier societies and water is repeated all over the world: people beside a spring at Boxgrove in England, people on the shore of Lake Mungo in Australia. These sites are of very different ages, but each represents some of the earliest evidence of human activity from its respective continent.
Looking back, we can identify various different ways in which people have been associated with wetlands. In the great raised bogs of northwestern Europe, for example, wooden trackways dating from prehistoric to medieval times show that people persistently sought to travel into and across the bogs. In New Zealand, in the period before European contact, the Maori built pa, defensible settlements on hilltops and in swamps - those associated with the swamps around Lake Mangkaware on North Island were heavily defended with wooden palisades, behind which people lived in substantial wooden houses.
At times, people have regarded wetlands as suitable places to bury their dead, and archaeological excavation has recovered evidence for the ceremony and ritual associated with the burials. One remarkable site is the pond at Windover, near Cape Canaveral in Florida, which was used for burials about 8,000 years ago. Some 300 people were buried here, wrapped in mats or blankets made from plant fibres and accompanied by grave goods made from bone, antler and plant materials. Perhaps the most poignant evidence from Windover is the skeleton of a child who suffered from spina bifida, a disease still afflicting humans today. The Windover people were nomadic and must have carried the child and devoted special care to it, for all of its 15 years.
Wetlands have been seen as a link between daily life and other worlds, a place where it is possible to come closer to gods and spirits, a place indeed where some of those other beings lived. In this light, wetlands can become places to make offerings. In northern Germany and Denmark nearly 2,000 years ago, in the long, narrow valley of Nydam in southern Jutland, warriors offered to their gods the booty from successful expeditions, including spears, swords, painted wooden shields and at least three large, impressive ships.
How have we documented so much information about the development of wetlands and their long association with people? Quite simply through the painstaking work of archaeologists Their efforts have traced wetland development over thousands of years through scientific analyses of the deposits laid down in the wetland body - the clays, silts and peats which lie between bedrock and the surface. Information about local vegetation has come from analysis of pollen and other plant remains; molluscs and insects such as beetles shed further light upon local conditions of the past. Even changes in the water quality of a wetland, such as levels of salinity, pH and temperature, can frequently be determined. Such studies often provide information about environmental development in the region surrounding a wetland, leading to a better understanding of cultural developments in the same area over time.
In wet, temperate climates, some areas of wetland have developed into raised bogs, great domes of mossy Sphagnum peat. Conditions in a raised bog particularly favour the preservation of environmental evidence and of a range of organic archaeological material, including wooden structures and objects and occasionally the remains of people themselves, including skin, hair, clothing as well as skeletal remains -even evidence of their last meal!
Wetlands of great antiquity, as well as those of recent times, thus contain the evidence of their own history, and of conditions in the surrounding region during their lifetimes. They have the potential to preserve significant testimony of human activity, of the cultural values that people attached to the wetlands in the past. Wetlands have always been vitally important to people and, as such, they form a significant component of our cultural history. In their efforts to manage wetlands so as to alleviate ongoing threats to their natural functions and values, environmentalists are increasingly coming to understand the necessity for planning so as to conserve this irreplaceable cultural heritage as well.
The Ramsar Convention on Wetlands
