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Nova Scotia Wet Places - Bogs and Fens

Eastern Habitat Joint Venture

Carpets of sphagnum moss, tea-coloured waters, an open expansive view, stillness and the sound of water squishing beneath your feet - these are characteristics of a bog or fen. Bogs and fens are each very distinctive in their appearance and functioning, and the unique collection of wildlife they support. Though a harsh, somewhat unproductive habitat for wildlife, bogs and fens play big roles in maintaining the environment.



Description
Bogs and fens are poorly drained areas that are covered with either sphagnum moss or grass-like sedges and are filled with decomposing plant matter or 'peat.' It is this overwhelming presence of peat that largely distinguishes bogs and fens from other wetlands. Generally, bogs and fens - also called 'peatlands' - appear quite similar. On the surface, both are mostly open areas covered with knee-high shrubs and either moss or sedges, and bordered by coniferous trees, primarily black spruce.


Sphagnum moss


Bogs are like bowls full of peat and water. They tend to be self-contained wetlands whose sole source of water is rainfall. Bogs typically develop in shallow low lying areas over layers of bedrock. Because rainwater can provide only limited nutrients, bogs are the most nutrient-poor type of wetland. Of the different kinds of wetland present in Nova Scotia, bogs are the most numerous.


Fens are connected to small streams or lakeshores and may also receive water from surrounding uplands. Unlike in bogs, water slowly moves through a fen. Importantly, because fens have an outside supply of nutrient-enriched water they are able to support lusher vegetation and a greater variety of wildlife than can bogs. Nevertheless, fens are still relatively nutrient-low habitats compared to most other types of wetlands. Fens, contain an abundance of sedges, rushes and grasses.


Wildlife of bogs and fens

Many types of animals visit peatlands, but few actually remain there year-round. The water of fens and particularly bogs is cool, acidic and oxygen-poor due to the presence of moss and peat. The process of decomposition requires oxygen. Consequently, the slow breakdown of peat limits the amount of freely available oxygen. Few insects and plants can grow under such severe conditions, and therefore the diversity of life in peatlands is low.


Mosquitoes, blackflies, midges and dragonflies thrive in peatlands, as do some wet-tolerant trees and shrubs such as black spruce, leatherleaf and rhodora. In order to overcome the nutrient-poor conditions of peatlands, some plants, such as the pitcher plant, sundew and bladderwort, actually trap and consume unwary flies, beetles and other insects.


Animals, like brown bullheads (catfish), pickerel frogs, and porcupine, do occur in fens, but usually not in bogs. The blandings turtle, one of Nova Scotia's species at risk, is a resident of fens.


Pitcher plant


Regular visitors to peatlands include snowshoe hare, moose, black bear, shrew, green-winged teal, swamp sparrow and northern ringneck snake.

Bogs, fens and the environment
Bogs and fens are important regulators of the environment. Like all wetlands, bogs and fens help control water levels throughout the year by absorbing water during wet periods and then later releasing it during times of drought. Peatlands also remove toxic chemicals from water, thus helping to purify ground water.

Global climate change, or the 'greenhouse effect,' is a major environmental threat. The gradual warming of the planet is altering weather patterns and influencing all life on earth. The problem stems from an accumulation of carbon dioxide in the earth's atmosphere which causes heat to build up on earth.

Fortunately bogs and fens combat the greenhouse effect by serving as huge storage depots for carbon (in the form of peat). Carbon that is locked up in peatlands cannot make its way into the earth's upper atmosphere. Additionally, bogs and fens actually cool the region surrounding them by giving off moisture. The connection between soggy peatlands, the atmosphere and the health of the planet is incredible, but true.


Conservation
Fens and bogs are wet, somewhat unproductive biologically and often located in out of the way places. Consequently, they are largely ignored by land developers, recreational users, and farmers. However, peatmoss is sold to gardeners and farmers as a soil conditioner, and in some societies peat is routinely burned as a source of heat. Commercial harvesting of peat occurs throughout the world, including Nova Scotia. The layers of peat in a bog or fen usually have been accumulating for several thousand years! Therefore, once a bog is harvested it essentially disappears.

Fortunately, bogs and fens in Nova Scotia are being credited for their contributions to the environment and as habitat for many species at risk, including rare plants such as eastern mountain avens, thread-leaf sundew and grass pink. Indeed, peatlands are essential pieces of nature's overall puzzle and must be treated preciously.