Fauna
Habitat types represented in the park include saltmarsh, mangroves, sheltered intertidal mud flats and subtidal soft sediments in tidal channels. Mangroves are a vital part of the bay ecosystem and provide important habitat for numerous invertebrates including crustaceans (crabs, shrimps and sand hoppers), marine snails and bivalves, adult and juvenile fish. The adjacent coast, including the coast of Quail Island, supports good examples of sand heathland, coastal saltmarsh, and low woodland dominated by coast manna gum. Quail and Chinaman Islands are considered to be of State botanical and zoological significance. The relatively undisturbed mangrove (Avicennia marina) and saltmarsh habitats of Watson Inlet and Quail Island are also of State significance as some of the most intact communities in Victoria. The mudflats within the Marine National Park are of national significance primarily as a feeding habitat for wader birds and other water birds. Many water birds and wader birds roost among the mangroves and nearby coastal woodlands. The mangroves are also vital habitat for the life cycles of crabs, shrimps, sand hoppers, marine snails and bivalves, and well as important feeding areas for adult and juvenile fish. While not actually eating the mangroves directly, the leaves that fall into the water are decomposed and form detritus, a major food source for scavenging and filter feeding animals in the Bay. Over 295 bird species have been recorded in Western Port with 32 of these being international migratory waders that fly from as far away as Siberia, Japan, China, and Alaska during our summer months. The Yaringa Marine National Park forms an important part of the Western Port Ramsar wetlands that have been listed under the International Treaty for the Protection of Migratory Wader Birds (Ramsar Convention). Eastern Curlew (Numenius madagascariensis
The Eastern Curlew is the largest of a number of migratory wader birds that make their home for several months each year in the Yaringa Marine National Park. Eastern Curlews nest largely in Siberia in a hollow scoop on the ground filled with a layer of gras and leaves. Migrating during the northern hemisphere winter to wetlands in southern Australia, these magnificent birds usually arrive in August and depart in March or April. Occasional non-breeding birds remain in Australia for the entire year. Eastern Curlews feed on a variety of invertebrates such as crabs, molluscs, or worms that they collect from the mudflats with their long probing beaks. The rich mudflats of Western Port provide these animals with energy to return back to eastern Asia and successfully breed. The survival of this species this depends on protecting habitat at both ends of their flight path. Geological, Hydrological and Landform Features Western Port occupies part of a depression caused by faulting along the edges of the Bay, described by geomorphologists as the Western Port sunkland, between the Mornington Peninsula to the West and the South Gippsland Highlands to the East. Although techtonic movements played an important part in the evolution of Western Port, there is no simple relationship between the fault pattern and the present coastline. The outlines have been modified over time by erosion and deposition by runoff and rivers, as well as the efffects of marine submergence and the shaping of coastal and sea floor morphology by waves and currents. Rivers draining into Western Port are predominantly small in flow, resulting in Westerport being essentially a marine, rather than estuarine inlet (as is Port Phillip). However, there are vast quantities of muddy sediment in and around Western Port, forming shoals and marshlands. Western Port has been an environment in which muddy sediment could accumulate during Pleistocene and Holocene times. The mud (consisting of silt, clay and orgnaic matter) was derived partly from inwashed river sediment, and partly the reworking by waves and tidal currents of fine-grained material derived from outcrops around and beneath the bay. Because of the relatively sheltered waters lacking waves of the open coast these muds have formed extensive layers across much of Western Port. These muds are generally black in colour and have a strong sulphur smell, due to the presence of iron and hydrogen sulphides, indicating that there is little oxygen that penetrates into the mud. The sulphides are produced by bacteria that can utilise sulphate from the water for their chemical reactions rather than oxygen. In the northern parts of the bay, near Yaringa, the saltmarsh and mangrove fringe has built a terrace upward and outward in front of an early Holocene coastline that was generally sandy, with some cliffed sections. This former coastline developed about 6,000 years ago when sea levels were about 1.5 - 3m higher than at present . A sandy beach can be traced at the inner edge of the salt marshes along the north-western shores of the bay, around Quial Island and Chinaman Island, and on the northern shores of French Island. Near Yaringa it becomes a recurved spit, now completely enclosed by marshland. The mudflats of this area of national significance because of their importance as feeding habitat for wader birds. Between the mudflats there are some deep channels that carry the tidal flows into and out of the bay. Like other smaller bays tide times are often occur a number of hours after the tides on the open coast, due to the time delay in water entering and leaving these channels.
|
