Moonah woodland
Edwards Point Wildlife Reserve has the largest intact stand of moonah woodland that remains on the Bellarine Peninsula. Patches also grow around Swan Bay at Burnt Point, Swan Island, Stingaree Island and along Lake Victoria. Moonah, Coast Wirilda, Coast Tea-tree and Coast Beard-heath form the woodland’s canopy. Pink Fairies, Bower Spinach and Sea Celery grow in the understorey. Small bats, possums and birds feed, nest and shelter in the woodland.
Some of the twisted moonah trees have been estimated to be 300 years old. When their life began, moonah woodland covered coastal sand dunes between Edwards Point and Aireys Inlet and spread inland for up to five kilometres. It is now a threatened plant community in Victoria, with less than 10% of its original cover left.
Coastal saltmarsh
Narrow strips of coastal saltmarsh grow along Swan Bay’s western shoreline, around its islands and at Edwards Point. Coastal saltmarsh plays a very important role by reducing erosion, trapping sediments and pollutants, and providing shelter and food for fish, birds and other animals.
The salt-tolerant plants that grow in the saltmarsh include Shrubby Glasswort, Beaded Glasswort, Creeping Brookweed, Austral Sea-blite and Southern Sea-heath. Tussock grassland grows on higher ground away from the salt water and includes Chaffy Saw Sedge, Knobby Club Rush, Sea Rush and Prickly Spear Grass. Grey Glasswort grows around saltpans that form in areas of very high salinity, such as near the Swan Bay Jetty.
The health of the bay’s saltmarsh improved after fencing stopped its trampling by wandering livestock.
Tidal flats
When the tide ebbs from Swan Bay it uncovers more than 1200 hectares of tidal flats. Most life in tidal flats is below the surface where bacteria, algae and microscopic animals work to recycle nutrients.
Pipis, crabs and worms burrow in the mud to avoid dehydration as well as the fish and birds looking for them. Drifts of decaying seagrass give shelter and food for tiny sandhoppers, crabs and marine snails.
Migratory wading birds feed on the tidal flats and rest and roost in fringing coastal saltmarsh. When the tide returns, Black Bream and other fish swim in to feed on crabs and other small animals. Large wading birds, such as the Royal Spoonbill and White-faced Heron, search for food in the shallows.
Seagrass meadows
Seagrass meadows cover most of Swan Bay’s intertidal and subtidal areas and give protection to its shoreline. The seagrasses are the basis of the bay’s productivity, in part due to the ability of their roots to ‘fix’ nitrogen, much like legumes. They are also host to more than 250 animal species.
Tasman Grass-wrack, Heterozostera tasmanica, is the most common seagrass species and grows in deeper waters. Dwarf Grass-wrack, Zostera muelleri, is the main intertidal species.
Crabs, snails and young fish use the meadows as nurseries. Dead seagrass washed onto the shoreline or having sunk to the bottom is an important food source and habitat for many animals.
Seagrass meadows store significant amounts of carbon. Their protection will prevent carbon release into the atmosphere and help tackle climate change.
Marine Algae (Seaweeds)
Species of green, brown and red algae, also known as seaweeds, cover the deeper waters in the south and centre of Swan Bay. They are also be found among seagrass meadows where they can grow on seagrass leaves and be eaten by small snails.
Most seaweeds are known by their scientific names, such as the green seaweeds Caulerpa remotifolia and Caulerpa sedoides. Another green seaweed, Polyphysa peniculus, attaches itself to shell beds in the southern part of the bay. Sea Lettuce, an Ulva species, often grows on seagrass and hard substrates that include shells and rocks. It can form blooms where grazing animals are scarce and near stormwater outlets where nutrients are high.
Bare sand and mud
It might not look like much but the bare sand and mud habitat teems with life on and beneath the seabed. Small crustaceans known as amphipods and copepods live in the sand and mud where they recycle nutrients. Wading birds target them and also search for worms, bivalves and snails.
Although fish such as King George Whiting prefer areas where they can hide in seagrass, they also feed on Ghost Shrimp in sandy patches among the seagrass meadows. Other fish seen on bare sand and mud include the Small-mouthed Hardyhead, Greenback Flounder, Black Bream, Rock Flathead and Gummy Shark, as well as the Smooth Stingray, Banjo Ray, Southern Fiddler Ray and Spotted Stingaree. The Smooth Stingray is the world’s largest, up to two metres wide and more than four metres long.
Waterways
The Swan Bay wetlands include Lake Victoria and Freshwater Lake, which are protected in the Lonsdale Lakes Nature Reserve. More than 80 wetland species, including migratory shorebirds, have been recorded at Lake Victoria, with 60 seen at Freshwater Lake. A third lake, Lonsdale Lake, has been replaced by The Point canal estate.
Yarram Creek and Frederick Mason Creek are intermittent streams that flow into Swan Bay. At the time of settlement, Yarram Creek was described as having beautiful shady trees on both its banks. However, clearing of the catchment, erosion and grazing by livestock have removed most creek-side vegetation. Dams in the catchment have also reduced creek water flows. A small estuary is found at the mouth of the Yarram Creek.
Coastal dunes and beaches
Coastal dunes and beaches are found along Edwards Point Wildlife Reserve and on Swan Island and Sand Island. They provide protection from wave and storm attack for inland habitats.
Coastal dunes form when sand is blown to the back of the beach and colonised by grasses like Hairy Spinifex. Other plants follow and include the Rounded Noon-flower, Seaberry Saltbush, Running Postman, Coast Beard-heath and Coast Teatree.
The Nankeen Kestrel hovers above the dunes before dropping on to small birds, insects and reptiles. Silver Gulls are often seen noisily scavenging for scraps from beach picnickers, however they also eat worms, fish and crustaceans along the beaches. The Pacific Gull mainly feeds on molluscs, fish and birds.
Islands
Swan, Sand, Tip, Stingaree, Duck, Rabbit, Mangrove and Rat are the names given to Swan Bay’s islands. They are important refuges for remnant saltmarsh, moonah woodland and threatened animals and plants. Patches of moonah woodland and the endangered Coast Bitter Bush grow on Swan Island.
The critically endangered Orange-bellied Parrot has been seen feeding on the seventh fairway of Swan Island’s golf course. Sand Island is an important breeding site for the Fairy Tern and a roosting site for the Little Tern. Pied cormorants breed on Stingaree Island, the Royal Spoonbill roosts on Tip Island, and Duck Island is habitat for the Water Rat.
Image Attributions
1. Lake Victoria. Rosalind Smallwood
2. Marine algae and Zostera nigracaulis seagrass. Mark Norman. Museums Victoria - https://collections.museumsvictoria.com.au/species/15195