Pacific intertidal wetlands

Loss of intertidal wetlands in southern British Columbia

Loss of intertidal wetlands to urban, agricultural, and industrial development was greatest at the turn of the 20th century, but continues today due to the pressures of human population growth.38, 39 About 76% of B.C.'s population lives in coastal communities, mainly in the Lower Mainland and southeastern Vancouver Island.40 The population of coastal B.C. is projected to increase by almost one million people by 2025.5

Total loss of intertidal wetlands, mainly through dyking for agriculture in the early part of the 20th century, is estimated at 70% for the Fraser River estuary and 32% for major estuaries along the east coast of Vancouver Island.39

Photo: western Sandpipers, Boundary Bay © John Hayes
Boundary Bay is part of the Fraser River estuary. The extensive (5,000 ha)42 mud flats support the largest known migrant populations of western sandpipers and the largest Canadian winter populations of dunlins, black-bellied plovers, and great blue herons.43

There are over 440 estuaries in the Pacific Maritime Ecozone+, most with fairly small intertidal zones of 1 to 10 ha.41 The largest estuary is that of the Fraser River, with about 21,000 ha of intertidal wetlands remaining. Although estuaries occupy less than 3% of the coast,41 an estimated 80% of coastal wildlife, including birds, fish, mammals, and invertebrates, use estuarine habitat at some point in their life cycle.5 Estuaries are also important to surrounding land and water ecosystems because of their role in water filtration and nutrient cycling.41