Wetlands are among the world’s most ecologically diverse and valuable environments. They support an array of natural ecosystems and species, provide recreational opportunities and are important historical and landscape features.
The Port Phillip and Western Port region has more than 900 wetlands greater than one hectare in size, including the tidal flats of Western Port, with a combined area of more than 40,000 hectares.
Wetlands are important as habitat for many animals throughout their life cycles and provide refuge in times of drought. They are vital feeding grounds and nurseries for land, marine and freshwater animals. They store and supply critical components of the natural food chains for rivers and inshore waters. Hundreds of bird species depend on the region’s wetlands for all or part of their annual life cycles. Migratory birds travel to Port Phillip Bay and Western Port wetlands from as far away as Alaska, Siberia, China and Japan.
Nearly two thirds of the region’s natural wetlands have been lost due to draining, filling and other modification. The extent of the region’s deep-water marshes has decreased significantly due to the draining of the Koo Wee Rup Swamp. The draining of the Carrum Carrum Swamp has had a similar effect on the extent of shallow fresh-water marsh wetland systems in the region.
Human activity has also been responsible for new wetland environments created through the construction of reservoirs, storm water treatment ponds and sewerage treatment plants which now provide around 22 per cent of the region’s wetland coverage. The Western Treatment Plant at Werribee is recognised for its importance as a bird habitat and is part of one of the region’s Ramsar sites. A number of cities in Melbourne’s South East have also constructed man-made wetlands to treat stormwater run-off.
The ability of wetlands to capture nutrient and sediment loads in urban stormwater and the need to protect their biological functions has made them an important part of the work to protect water quality in Port Phillip Bay and Western Port.
The Port Phillip and Westernport CMA is working with a number of organisations and groups to protect priority Ramsar Wetland sites within the region. Overcoming threats from changing land use and water regimes and reducing the impact of pollution while also informing the community of the value of wetlands to broader environmental health are primary aims for the Port Phillip and Westernport CMA.