With a population of some 3.3 million, Melbourne is a sprawling city. Its Central Business District is quite compact, and has been referred to as a Golden Mile. The residential area, however, hemmed in by Port Phillip Bay to the south, extends for twenty kilometres to the west and north and double that to the east. Though there are more than a dozen National and State Parks within a morning’s drive of the suburbs, some of the most important work toward the protection of wildlife is done much closer to the city, and even within its boundaries.
At Werribee, on the south-western edge of the city, and covering an area of 11 000 hectares on the Port Phillip Bay coast, lies the Western Treatment Plant. This huge area was set aside in the 1890s to handle the sewage of the rapidly growing conurbation. Even today it treats the effluent of more than half Melbourne, including that of the 1.6 million inhabitants of the west, north and central suburbs and most of the city’s industrial waste. Much of this is cleaned by passage through a series of lagoons, in which solids progressively settle, and bacteria, helped by aeration and sunlight, purify the water before its discharge into the bay.
The lagoons, and Lake Borrie, which was created from a small swamp, are completely artificial. Apart from the treatment areas, there are rivers, estuaries, dry plains, woodlands and mudflats. These have all been enriched by nutrients from the plant’s discharges, which feed a large invertebrate population. This, in turn, has attracted huge numbers of birds to Werribee, with the result that in 2001, the wetlands were listed under the Ramsar Treaty as of international importance.
Pelicans at Werribee
More than 270 species of bird have been recorded at Werribee and its smaller satellite protected areas, Point Cook and Cheetham wetlands. This is almost as many as in the world famous Kakadu National Park in the Northern Territory. Bird watching and fishing are allowed all year round, but only by permit. With little human interference and no shooting, this has become a wildlife haven.
Upward of 60 000 birds arrive here in the autumn, including up to 20 000 waders. Many have migrated from Alaska, Siberia, Japan and China. Records show that some ringed birds have made the journey at least ten times. Large numbers of Australian teal, shoveller and shelduck winter here along with grebes, coots, pelicans, black swans and white ibises. Waders include red-necked avocet, pied stilt and the much rarer Cox’s sandpiper, buff-breasted sandpiper and Asian dowitcher. 700 pairs of pied cormorant breed here and raise their chicks during winter. Several artificial perches have been built around Lake Borrie to replace trees that have either fallen or rotted away, making this the only breeding area for cormorants in Victoria. Marsh harriers and white-bellied sea eagles are among the birds of prey that are often seen. About 60 orange-bellied parrots migrate to Werribee from Tasmania for the winter. This is an extremely endangered bird, with an estimated total of 150 surviving in the wild.
Werribee is no longer the sole treatment plant for Melbourne, though it remains the largest. As the city expands, there are new housing developments in the surrounding area. These have necessitated changes in sewage handling. Odours need to be eliminated. The lagoon system is being expanded. The emphasis has moved toward recycling rather than discharge. These plans include measures to conserve the flora and fauna of the wetlands, and make Werribee a world leader in this field.
The Western Treatment Plant was originally set up to divert sewage from the Yarra River, Melbourne’s main watercourse, which flows into the city from the north-east. The several wooded parks that line the riverbanks from the suburb of Warrandyte almost into the city centre illustrate its success. The purpose of some of these parks is largely recreational, while others are dedicated to quite specific conservation projects.
Warrandyte State Park lies 24 kilometres from the city centre. Scattered around its slopes are relics of Victoria’s gold rush, which began here in 1851. Mining continued into the early 20th Century, by which time around 250 miners were employed here. At Pound Bend, a tunnel was dug to divert the river and so expose its bed for mining. At the same time, the hills were completely denuded of trees. Since the closure of the mines, the area has reverted to its natural appearance and fast-growing manna gum trees have recolonised the riverbanks and hillsides. Many of Australia’s iconic animals, kangaroos, wallabies, wombats and platypus have returned.
Koala at Pound Bend
At Pound Bend, a reserve within the park has been created specifically for koalas. There are footpaths through the forest, and though the koalas may at first be difficult to spot, they can more readily be seen when one knows what to look for. The trees are very tall, and the animals, even at their most active, are almost immobile. Nevertheless, they usually appear as incongruous swellings among the higher branches of the eucalypts.
A short distance to the west of Pound Bend is a tiny, and even more specialised protection area, the Pauline Toner Butterfly Reserve. The Eltham Copper butterfly was first recorded in 1938. Twenty years later, it was presumed extinct, but a small number were rediscovered in 1987. It is now known to be present at fewer than twenty sites at three widely separated localities in Victoria.
The numbers of this very rare butterfly are low because of the isolation of its populations, the loss of habitats and its unusual life cycle. The adults lay their eggs only on the Sweet Bursaria plant, on which the caterpillars depend for their food. In their nocturnal foraging, they are accompanied by Notoncus ants, which feed on sugar secretions on the caterpillars’ skins. In return, the ants protect the caterpillars from insect predators.
The Pauline Toner reserve is named after Victoria’s first woman cabinet minister, who was an active campaigner for the butterfly. Volunteers carry out conservation work, such as revegetation, protection of habitat and track management, with financial support from Victoria’s Department of Sustainability and the Environment.
As everywhere in Australia, the Aboriginal names have been overlaid with later appellations that reflect the origins of the European settlers. So the Yarra snakes its way between the suburbs of Doncaster and Heidelberg, and past an almost unbroken series of parks and reserves, before it comes to the Yarra Bend Park, where a unique and highly successful experiment has been carried out.
Flying foxes on the Yarra River
For two decades, fruit bats, also known as flying foxes, inhabited the Royal Botanical Gardens in the centre of Melbourne. As their numbers approached 30 000, the damage they did to the trees became devastating. As the species, on a national scale is threatened, culling was not an option. Relocation was the only solution. In an operation that was the first of its kind in the world, the bats were moved to a site at Horseshoe Bend, farther up the Yarra. When they tried to return, or invade nearby residential gardens, they were subjected to noises which drove them back. Over a six-month period, they moved five kilometres downstream and eventually settled at Yarra Bend.
An area of 26 hectares has now been allocated as a flying fox reserve, and the vegetation there will be continually regenerated until it, and the bats reach a sustainable level. An almost identical problem has arisen in Sydney, so the pioneering work in Melbourne is now being seen as offering a possible solution.