The four major categories of wetlands:
Marshes, Swamps, Bogs, and Fens

Many classifications fall under each of those categories.
Wetlands Profile

The Great Blue Heron Nature Reserve is a combination of marsh and swamp wetland types.

MARSH
Marshes are wetlands that are frequently or continually covered in water and predominant plant species include soft-stemmed vegetation adapted to saturated soil conditions, such as cat tails. In marshes, most of the water is received via surface water, although some marshes are also fed by groundwater. At the reserve, our cattail marshes are fed via surface and ground water. The Salwein Wetlands found in the reserve are undyked and connected to the Vedder River, so they are specially designated as undyked floodplain wetland habitat.

Across the world, there are many types of marshes ranging from prairie potholes to the Everglades, coastal to inland, freshwater to saltwater. A marsh provides multiple functions and values including recharging groundwater supplies and moderating streamflow by providing water to streams, which is especially important during periods of drought. In addition, the presence of a marsh in a watershed helps to reduce damage caused by floods by slowing and storing flood water. The Salwein Wetlands at the Great Blue Heron Nature Reserve, which are greatly comprised of cat tail marsh help to diminish impacts of flooding in this undyked floodplain wetland habitat and marsh vegetation and microorganisms also use excess nutrients for growth that would otherwise pollute surface water, such as nitrogen and phosphorous from fertilizer.

Non tidal marshes, like those found in the Great Blue Heron Nature Reserve, contain highly organic, mineral rich soils of sand, silt, and clay. Because of their high levels of nutrients, freshwater marshes are one of the most productive ecosystems on earth and can thus sustain a vast array of plant communities which, in turn, support a wide variety of wildlife. The diversity of life that is sustained within a marsh habitat is disproportionate with its size due to its incredibly high productivity. Within the marshes found in the Salwein Wetlands in the Great Blue Heron Nature Reserve, plants such as cattails, reeds and bulrushes provide excellent habitat for waterfowl and other birds such as great blue herons (blue listed species at risk) and red-winged blackbirds. Small mammals such as beavers, river otters, and muskrats also call this marsh habitat home, not to mention amphibians such as the northern red legged frog (blue listed species at risk), reptiles such as the common and northwestern garter snakes, and insects such as the damselfly and autumn meadowhawk dragonfly (red listed species at risk).

Unfortunately, the Salwein Wetlands has faced a huge amount of degradation over the years due to human development. Impacts include major reduction in size and excessive deposits of nutrients and sediment from construction and farming. Invasive plant and animal species also threaten to further reduce an already diminishing diversity. These ongoing threats highlight the importance of what we are doing at the Great Blue Heron Nature Reserve to ensure the ongoing conservation of this wetland habitat.

SWAMP
Swamps are areas of land that occur along the flood plains of rivers, lakes, streams, and oceans. Swamps are permanently saturated with water; however, they do not need to be completely filled with water year-round. Mineral content in swamps is high due to the origin of soils in which they occur, while nutrient contents vary. Swamps are primarily composed of tree and shrub plant species, making them different from marshes which are composed of more grass and sedge plant species.

Swamp waters are classified as slow-moving and can either be freshwater or saltwater; the Chilliwack/Vedder River is home to many different freshwater swamps. Freshwater swamps are typically found inland and inhabit old streambeds and oxbow lakes that are adjacent to rivers and streams. Swamps occur in hummocky terrain and have saturated soils known as Gleysols. Nutrient levels in swamps are dependent on the type on vegetation; coniferous swamps have poor to moderate nutrient levels while deciduous swamps have moderate to high nutrient levels. Swamps typically have less than 40 centimeters of peat occupying the bottom, differentiating them from bogs and fens. Increased vegetation helps to slow down water movement during flood events, which in turn decreases the risk of erosion and sedimentation and increases the overall health of the ecosystem. Swamps are named by the dominant plant species in the surrounding area; The Great Blue Heron Nature Reserve has classified one swamp type as being Sitka Willow – Pacific Willow – Skunk Cabbage. This swamp type is found in two areas amongst the reserve and occurs sporadically at low elevations throughout the Coastal Mountains, Georgia Depression, and coastal transition areas of the Interior at peatland margins and in floodplain depressions.

Traditionally, swamps are considered ominous because of the creatures that occupy them, however, swamps support a variety of biodiversity, making them productive wetland ecosystems. Swamps support many different mammal, bird, reptile, amphibian, and insect species, which are dependent on the ecoregion in which the swamp is located. Along the Chilliwack/Vedder River, expect to find Wood Ducks and Belted Kingfishers, which rely on swamps and associated vegetation for nesting and feeding purposes. As well, different salmon species depend on the slow-moving swamp waters for fry-rearing while beavers depend on swamp ecosystems for lodge-building. Insects such as the Autumn Meadowhawk (blue-listed species at risk) rely on swampy lowlands at the reserve for habitat.

Like all wetland ecosystems, swamps are slowly diminishing. This is mainly due to anthropogenic causes, such as fragmentation of landscapes, swamp drainage for agriculture, and land clearing for urban development. As well, the introduction of invasive species affects the native species and lowers the overall health of the wetland ecosystem. There are currently two swamp wetlands found on the Great Blue Heron Nature Reserve (see map, top of page).