Aquatic Habitat


Wetland ecosystems are adapted to wet conditions as they are surrounded by water at or above the surface or within the root zone of plants for part of, or the entire year. The dependence of these wetland ESAs on water varies considerably. Some depend on water all year while others can survive if there are drier conditions during the summer growing season. Six wetland ecosystems have been identified and include bog, fen, marsh, swamp, shallow water, and wet meadow. However, wetlands often encompass a range of classes because of successional processes and disturbance. These types of wetlands can be categorized as either peatlands or mineral wetlands.

Bogs and fens are in the peatland category and are characterized by continuously wet, organic soils that accumulate over hundreds to thousands of years because the rate of new plant growth exceeds the rate of decomposition. Some plant species typically found in peatlands are shore pine, western hemlock, and various species of Sphagnum moss.

Mineral wetlands encompass the remaining classes of wetlands: marsh, swamp, shallow water, and wet meadow. The gradual accumulation of organic matter does not occur in mineral wetlands because of the ever-changing water levels and higher nutrient levels that promote decomposition. The typical plant species found in mineral wetlands vary depending on the type of wetland and can range from skunk cabbage to yellow pond-lily to western red cedar.

Only 1.6% of the region of Nanaimo is wetland ESA. You may observe an array of wetland classes at the Nanaimo River estuary.



A riparian ecosystem is an area of land along a river, stream, lake or wetland that is wet enough to support a variety of life that is distinct from the vegetation in freely drained upland sites. Its area extends along a gradient of decreasing soil moisture until it reaches upland sites. Riparian ESAs are vital to the survival of many plant and animal species. It is approximated that over half of the terrestrial vertebrates at risk in BC depend on Riparian ESAs for many of their needs and, without theses ESAs they would be at much greater risk. The types of plants that dominate Riparian ESAs are typically those that depend on an abundance of soil moisture to survive such as willow, cottonwood and salmonberry. Riparian ESAs are important bacause they decrease flood effects and provide wildlife habitat and corridors. Only 2.3% of the area of Nanaimo is Riparian ESA as seen along the Nanaimo, Millstone and Chase rivers.



An estuary is a partially enclosed body of water where saltwater from the Straight of Georgia mixes with the fresh water from streams, creeks and rivers. The Nanaimo River estuary is a significant local example.

A large number of organisms can be found in estuaries, organisms specially adapted to 'brackish' water. Estuaries are among the most biologically productive ecosystems on the planet. More than 2/3 of the fish and shellfish people eat spend some part of their life in an estuary. Estuaries also act as filters for terrestrial pollutants and provide some protection from flooding.

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