Can you tell a swamp from a marsh, or a bog from a fen? Sometimes its not easy. Canada is home to more than 25% of the world's wetlands. Wetlands and the vegetation they contain provide important habitat for many birds and animals, filter water, and are a storehouse for carbon. Wetland environments are often found side by side, and their borders blur. A marsh may ring a pond with open water. A fen may be nestled between a swamp and a bog. Wetlands continually develop from the decomposition of plant material which in turn supports the growth of newer water-loving plants. Continuous saturation with water prevents total conversion to gaseous carbon dioxide and promotes the slow accumulation of humified peat materials. In Canada’s north, vast expanses of fens and bogs are known as muskeg, and any given fen might be in the midst of a several-hundred-year-long transformation into a bog.
The following are the basics to help you differentiate Bogs, Fens, Marshes, Swamps and Shallow Open-Water.
Bog: These are the granddaddies of wetland ecosystems. They are peatlands 10,000 years or more in the making. Bogs tend to be disassociated from nutrient-rich ground water or surrounding mineral soils; cut off from groundwater. A bog’s water comes only from accumulated snow melt and rain. Peat (acidic, oxygen-poor, decomposed vegetation) is a haven for sphagnum mosses that form thick reddish or greenish cushions. Near the surface, the materials are usually undecomposed (fibric), yellowish to pale brown in color, loose and spongy in consistence. Bogs may be treed or treeless and are frequently characterized by a layer of ericaceous (found most commonly in acidic and infertile growing conditions) shrubs. Sphagnum mosses dominate, but some sedges may also grow. Sphagnum is a genus of approximately 380 mosses, commonly known as sphagnum moss or bog moss. Sphagnum peat is extremely acidic (pH <4.5), with a very high fiber content. At depth they become darker, compacted, and somewhat layered. Bogs are associated with slopes or depressions with a water table at or near the surface in the spring and slightly below it during the remainder of the year. Look for tufted cotton grass, Labrador tea, cranberries, blueberries, songbirds, foxes, weasels, fishers, and hawks. Bogs consist of sphagnum or forest peat formed in an ombrotrophic (dependent on atmospheric moisture for its nutrients) environment caused by its slightly elevated nature.
Fen: Fens are like bogs-in-the-making: with peat less than 40 cm (16 inches) deep, they’re less acidic and draw on groundwater. The vegetation can be perched or floating. Fens consist mostly of sedge peats derived primarily from sedge plants with inclusions of partially decayed stems of marsh grasses and trees such as cedar or dwarf birch mixed in. Sedges are part of the Sedgesare family which are grass-like flowering plants of some 5,500 known species. Sedges are characterized by having stems with triangular (cf. round) cross-sections, with leaves arranged spirally around the stem. Sedges typically form a mat of vegetation extending around and towards the centre of shallow ponds. Sedge peat usually moderately well to well decomposed, dark brown in color, with fine to medium-sized fibers but may be well decomposed and black with fine fibers. Decomposition often becomes greater at lower depths. They are associated with relatively open peat lands with a mineral-rich water table that persists seasonally at, or very near, the surface.
Marsh: Characterized by still or slow moving water supporting stands of tall grasses, cattails, bulrushes, water lilies, pickerelweed, and blue flag iris. The marsh is the wetland we most recognize. They usually occur on the edge of a lake or a pond. A marsh may dry up seasonally, and it boasts rich mineral soil. Marshes serve as habitat for a host of species, including muskrats, ducks, marsh wrens, and turtles.
Swamp: If you see tall trees, you’re likely in a swamp. Swamps are peat-covered forests or forested peat-filled areas where the water table is at or above the peat surface usually located are near large lakes and rivers. The dominant peat materials are shallow to deep mesic to humic forest and fen peat formed in a eutrophic environment resulting from strong water movement from the margins or other mineral sources. Swampland lies either beneath nutrient-rich water or is water logged (if you dig a hole it will immediately fill with water). The peat is usually moderately well to well decomposed and has a dark brown to reddish brown matrix the more decomposed materials are black in color. It has an amorphous or very fine fibered structure and somewhat layered macrostructure and contains a random distribution of coarse- to medium-sized woody fragments. There may be layers of larger woody particles consisting of stems, roots, and trunks of coniferous tree species. A swamp is populated by woody plants: thickets of willows and alders, or stands of black spruce, tamarack, or poplar. The fiber content is intermediate between sphagnum and fen peats. These materials are associated with stream courses, lake edges, subsurface drainage, glacial depressions, and bog margins. Standing to gently flowing waters occur seasonally or persist for long periods on the surface. The substrate is usually continually waterlogged. The vegetation cover may consist of coniferous or deciduous trees, tall shrubs, herbs, and mosses. Rabbits and moose love these moody, misty habitats, as do skunk cabbage, swamp sparrows, moles, mice, and many waterfowl species.
Shallow Open Water: Call it a pothole, a pond, or a slough (pronounced “slew”) is a small, shallow, standing body of water up to two metres deep. It may be ringed with marsh or serve as the transition between lake and marshland. Duckweed, milfoils, water lilies, and water hyacinths flourish here. Hibernating frogs burrow in the mucky bottom. Gutweed, a notable pond plant, fills with air, floats, and attracts hungry insects with a slimy coating of bacteria.
============================
To claim this earth cache message or email your answers to to the CO for the following questions . Do not post your answers on the cache page with your log or it will be deleted.
- Based on the basic descriptions provided above, what type of wetland is this? Take a look at the sign at the posed cores for some help, but as you may gather from the above descriptions there may be more than one correct answer and the sign might not cover everything. It is important here to explain the reasoning for your answer.
- To prove you were actually at the site, go to the mile marker on the opposite side of the trail and tell me the name of the local sponsor indicated on the bottom of the sign. Failure to send the correct name of the sponsor may result in your log being deleted.