Bioregions: Warrnambool Plain, Otway Plain, Gippsland Plain
The Bioregional Landscape
The Natural Capital of the Landscape
Land Management Themes
Tables and Charts for the Coastal Plains
The Bioregional Landscape
The Coastal Plains area consists of several segments of coastal plains and hinterlands up to 200 metres in altitude, extending from Tyrendarra in the west to Lakes Entrance in the east and including Geelong, eastern Melbourne and the Mornington Peninsula. The area has a temperate climate with rainfall varying from about 500 to 1100 mm, typically with higher rainfall in winter. Adjacent areas of higher altitude (e.g. the Otway and Strzelecki Ranges) produce rainshadows in some parts of the area.
The area is synonymous with the South East Coastal Plain IBRA region and includes three Victorian bioregions.
The identifying features of the Warrnambool Plain are nutrient deficient soils over low calcareous dune formations and the distinctive cliffed coastline. Much of the limestone has been overlain by more recent sediments, and between the limestone dunes, areas of swamplands are characterised by highly fertile peats and seasonal inundation. The area east of Warrnambool is characterised by deeper soils of volcanic origins overlying limestone, which are dissected by streams.
Prior to European settlement, the Girai wurrung and the Dhauwurd wurrung were the Aboriginal people of the Warrnambool Plain, with the population mainly concentrated in open or lightly timbered country with access to permanent water. European occupation, mainly by graziers, commenced in the late 1830’s. The major population and commercial centre of the bioregion is now the coastal city of Warrnambool. Most people live in towns on or near the coast and in smaller inland towns. Long established tourist destinations include Port Campbell National Park, The Great Ocean Road and the adjacent Bay of Islands Coastal Park. A recent tourism feature during the winter months is the annual visitation of Southern Right Whales to Logans Beach at Warrnambool. Sheep and cattle grazing are widespread land uses, however the prime agricultural focus of the bioregion is the dairy industry. The coastal waters of the region support Southern Rock Lobster and abalone fisheries.
The Otway Plain includes coastal plains, river valleys and foothills from the Bellarine Peninsula west to Princetown. A small isolated component at Werribee, on the western shore of Port Phillip Bay, is included.
The bioregion is characterised by coastal heathland and woodland, and open forests with heathy understoreys dominated by Brown Stringybark and Messmate. Dry sclerophyll forest dominated by Mountain Grey Gum and Messmate occurs around the Otway foothills. River Red Gum woodlands occur along some drainage lines. The bioregion is drained in the east mainly by the Barwon River (which originates in the Otway Ranges) and its tributaries, and several small coastal streams. In the west the bioregion is drained mainly by tributaries of the Gellibrand River, although some streams flow north to lakes Corangamite and Colac located in the Victorian Volcanic Plain.
Prior to European settlement, the Watha wurrung Gulidjan, and Djargard wurrung lived in the area including the Otway Plain. They were mainly concentrated in open or lightly timbered country with access to permanent water. European occupation, mainly by graziers, commenced in the late 1830s.
Today most people live in towns on or near the coast and in smaller inland towns. Part of the greater Geelong urban area occurs in the bioregion, with Colac being the next largest city (on the edge of the bioregion). Smaller urban areas include Anglesea and Birregurra. The single largest land use is agriculture, with the focus on sheep and cattle grazing and dairy farming. Brown coal is mined near Anglesea.
The Gippsland Plain includes lowland coastal and alluvial plains characterised by generally flat to gently undulating terrain. The coastline is varied and includes sandy beaches backed by dunes and cliffs, and shallow inlets with extensive mud and sand flats. The vegetation includes lowland forests, grasslands and grassy woodlands, heathlands, shrublands, freshwater and coastal wetlands, mangrove scrubs, saltmarshes, dune scrubs and coastal tussock grasslands.
The bioregion extends from the Melbourne Central Business District and the Mornington Peninsula through parts of central and south Gippsland to Lakes Entrance in the far east. A number of rivers and streams including the Yarra, Bass, La Trobe, Thompson, Macalister and Avon drain the bioregion.
The bays, beaches, estuaries and rivers of the bioregion provided a rich source of food for the original Aboriginal occupants. Fresh and saltwater fish and shellfish were harvested and numerous shell middens along the coast indicate that this was a common food source. The Gunai-Kurnai Nation, which included several language groups were centred on the coastal plain of South Gippsland and the La Trobe Valley, whilst the Bunurong were found along the coastal plains from Wilsons Promontory to Port Phillip Bay.
The Gippsland Plain is now the most populated bioregion in Victoria, including the demographic centre of Melbourne and major populations on the Mornington Peninsula and in the La Trobe Valley.
Outside the metropolitan suburbs south-east of Melbourne, the major industries are dairy, sheep, beef and potato production. Major commercial reserves of brown coal are centred around the La Trobe Valley which is the principal electricity-producing area in Victoria. Some hardwood and softwood production occurs, mainly within Mullungdung, Won Wron and Alberton State Forests. The bioregion includes many important coastal parks associated with the Mornington Peninsula, Westernport Bay and the Gippsland Lakes.
The Natural Capital of the Landscape
At the time of European settlement the Coastal Plains were dominated by lowland and foothill forests, heathy and grassy woodlands, and coastal scrubs and grasslands. There has been substantial clearing of all vegetation types, particularly those on the deeper more fertile soils, with Lowland Forests and Heathy Woodlands remaining the most abundant.
Coastal Heathlands and Heathy Woodlands are known for their diverse ground floras, particularly of terrestrial orchids, and are communities in which the importance of maintaining natural ecological processes through appropriate fire regimes is recognised. The vulnerable Metallic Sun Orchid occurs at the Bay of Islands Coastal Park and Port Campbell National Park. The Anglesea area is famous for its diverse and prolific display of orchids. Important large stands of Heathland and Heathy Woodland remain on French Island. Three of the State’s four populations of the endangered New Holland Mouse occur in the Coastal Plains.
The coastal inlets that are adjacent to some of the plains are important areas for migratory waders and shorebirds in Australia, many species which are listed on the Japan-Australia Migratory Birds Agreement (JAMBA) and China-Australia Migratory Birds Agreement (CAMBA). Coastal areas are also important for a number of threatened species of shorebirds including Hooded Plover, both Pied and Sooty Oystercatchers, Orange-bellied Parrot and several species of terns.
Other interesting fauna occurrences of the Coastal Plains include: a Common Bent-wing Bat maternity cave at Lake Gillear, one of only three in South East Australia; a Southern Right Whale calving nursery at Logans Beach, east of the Hopkins River mouth, at Warrnambool; and the Giant Gippsland Earthworm of the Gippsland Plain.
Land Management Themes
The land management themes of the Warrnambool Plain are tourism and recreation, and agriculture, particularly dairying and some beef production. The bioregion has been largely cleared of native vegetation and modified with the introduction of pasture species. Approximately 90% has been cleared, although some significant remnants of Manna Gum/Messmate bushland remain on private land. The most significant of these, the Ralph Illidge Sanctuary, at Naringal, is owned by Trust for Nature and is managed as a conservation reserve.
There are few small conservation reserves in the bioregion. Jancourt forest block is the largest forest area. Several significant areas of riparian vegetation exist within the bioregion. Most significant are the nationally significant wetlands of Yambuck and Lower Merri wetlands, and portions of the Lower Curdies River. Most wetlands throughout the region are small and on freehold land. Areas in the Lower Heytesbury are affected by salinity.
Much of the Otway Plain is used for agriculture. The foothill forests support a minor forest industry based on timber, firewood and tea tree cutting, and private farm and commercial forestry is increasing. The largest forest area is the Wonga forest block about six km north of Simpson. Only a small percentage of the remaining native vegetation is in conservation reserves, mainly flora and fauna and lake reserves. Roadsides often retain the last areas of some high value biodiversity assets.
Significant urban areas with related recreational and tourism activities occur on the Bellarine Peninsula and are expected to increase.
Most of the coastline, including the major wetlands and inlets are public land covered by native vegetation and managed principally for nature conservation. However, the majority of the bioregion is private land most of which has been cleared of native vegetation to allow for agriculture, urban use and other development.
The bioregion contains substantial urban areas of Melbourne, including the eastern and south-eastern metropolitan suburbs, and this generates recreational and development pressure on the remnants and ‘green’ corridors which remain, typically along rivers and creeks. There are important reserves close to Melbourne such as Mornington Peninsula National Park, which are complemented by a series of regional and metropolitan parks. These parks and other features such as golf courses, frequently support local remnants of flora and fauna with some being significant sites for threatened species.
Tourism is a major industry along the coast including fishing, camping, hunting (in the east) and nature study. Fire has been important in shaping the ecosystems of the bioregion. Little information is available on the nature and extent of aboriginal fire regimes, but it is likely that fire patterns have changed considerably since European occupation. It is believed that in general, fires in grassy ecosystems, lowland and coastal forests and heathlands are now less frequent than before European occupation but individual fires are probably more intense.
The remaining native ecosystems, particularly those severely depleted such as open coastal scrubs and shallow freshwater wetlands, are all highly significant and vital for biodiversity conservation in the bioregion. Land for Wildlife properties play an increasingly crucial role in protecting habitat in these landscapes. Vegetation remnants are at risk from weed invasion, whilst native fauna are increasingly affected by introduced predators (fox and feral cat), and by fragmentation and modification of habitats.
Water quality is of importance for the significant wetland assets in the bioregion, in particular nutrient levels in relation to dairy operations need to be carefully managed. Drainage of shallow freshwater marshes continues to affect some wetland species of flora and fauna.
The biodiversity values of many of the rivers and streams are affected by grazing, drainage, salinity and pest plants. Nutrients and chemical run-off from the catchment also affects the quality of habitat in rivers, streams and lakes, and this has contributed to algal blooms occurring in wetlands outside the bioregion.
Grassy woodlands are only found in small fragments and regeneration of species such as Red Gum seldom occurs. Cattle grazing sometimes degrades native vegetation on private land.
Fire regimes, particularly in heathland habitats, are key ecological factors for species such as Rufous Bristlebird, Ground Parrot and New Holland Mouse, and need to be appropriately defined and integrated with other fire management activities. Fire regimes, inappropriate subdivisions and road and track maintenance can impact on threatened flora species with small and restricted populations, such as Merrans Sun Orchid, Wrinkled Buttons, Yarra Gum and Snow Gum.
A variety of mammals, reptiles and ground dwelling birds continue to be impacted by introduced predators (fox and feral cat), competitors (starlings in nest hollows) and other activities (recreation in foreshore nesting habitats). The quality of native fauna habitat in several streams and lakes is effected by the presence of introduced trout. The quality of native vegetation is reduced in many stands by introduced animals (rabbits, wild pigs, deer and goats) and by environmental weeds (including Serrated Tussock, Ragwort, Furze and Spartina in the Barwon estuary) and urban expansion.
Wetlands occur throughout the region. Lake Connewarre in the lower Barwon area is a Ramsar wetland and supports many waterbird and wader species. The extensive wetland area at Werribee (also Ramsar listed) is managed by Melbourne Water. The saltmarshes here support the endangered Orange-bellied Parrot following its autumn migration to the mainland. Most other wetlands are small, on freehold land and vulnerable to grazing and drainage.
The persistence of the different native ecosystems within the bioregion varies greatly according to the history of European settlement, and current land tenure and management. As a result, native ecosystems such as grasslands, grassy woodlands and heathy woodland communities whose habitat occurs principally on private land, are now severely depleted and threatened in the wild and largely restricted to small linear reserves such as roadsides. In contrast, coastal vegetation and some wetland systems are relatively secure.
Loss of native vegetation is still a major cause of habitat loss. Clearing is regulated by the Native Vegetation Retention provisions in planning schemes but some clearing on private land continues. Remnant areas of native vegetation on private land or roadsides are in many places being degraded by weed invasion, and grazing by stock, or disturbed by roadworks and incremental clearing. As these remnants include examples of ecosystems that are not well represented in reserves within the bioregion, management of these areas for biodiversity conservation remains a challenge.
Many species have evolved to rely on a particular fire regime to provide suitable habitat and facilitate regeneration. These regimes need to be identified and integrated with other fire management activities to avoid decline of species diversity. For example, insufficiently frequent fires in grassy ecosystems have lead to shrub invasion and loss of native grass and herb flora. Fires are currently too infrequent in coastal heathlands and individual fires too large and intense to maintain the fine scale mosaic of vegetation age classes required by New Holland Mouse, one of the bioregion’s endangered mammal species.
Introduced predators (particularly foxes) are considered a threat to the survival of native fauna, including species considered rare or threatened (e.g. Hooded Plover, Little Tern, Fairy Tern and New Holland Mouse).
The highly fragmented nature of remnant vegetation on private land greatly increases the vulnerability of stands to dieback. This is particularly evident in the grassy woodland communities where the small isolated nature of remnants and loss of fauna components has led to the breakdown of ecological processes and outbreak of disease and insect plagues. In recent years, Swamp Paperbark in reserves, roadsides and on private land in South and South-west Gippsland has suffered defoliation from infestations of Paperbark Sawfly.
The condition of the major rivers and streams is regarded as medium to poor due principally to siltation from accelerated erosion and nutrient run-off from agricultural land and intensive forestry production in the adjoining bioregion. Most banks have been largely denuded of native vegetation which has been replaced with introduced pasture grass or infested with willows. Many are unfenced and subject to grazing by domestic stock.
The biodiversity of freshwater and coastal wetlands in the east is being adversely affected by a number of factors including inappropriate flow regimes, increased brackishness associated with rising water tables, increased nutrient inputs, increasing incidence of algal blooms and infestations of European Carp. The documented decline in biodiversity values of these systems includes dieback of fringing vegetation associating with increasing salinity and substantial declines in population sizes of bird and fish species as a result of deteriorating water quality. Invasion by the environmental weed, Spartina is compromising the quality of habitat in intertidal areas.
The development of coastal habitats for housing and recreation is increasing the likelihood of human disturbance to previously isolated fauna populations, particularly shorebirds. In areas such as the Gippsland Lakes, the pressure from human disturbance is now sufficiently great to require active management of habitat areas to ensure the continuing breeding success of threatened species such as the Little Tern.
Of the 116 known threatened species and undetermined number of threatened ecological communities in this suite of bioregions there are:
- 74 listed vertebrates and plants, of which 29 have Action Statements;
- five listed invertebrates, of which two have Action Statements;
- four listed communities, of which none has an Action Statement.
Management ResponsesThe extensive depletion and fragmentation of many of the ecosystems across the Coastal Plains means that remaining areas of native vegetation and habitat are highly significant for biodiversity conservation. Regional Catchment Strategies have been prepared by the Port Phillip Regional Catchment and Land Protection Board and the various Catchment Management Authorities across the area. These strategies have identified the importance of biodiversity in the area and of addressing conservation in an integrated manner with other catchment health issues. Regional Vegetation Plans are currently in production which, when approved and implemented, will provide local government and referral agencies with guidelines for the protection of remnant native vegetation on private land and land managed by shires and statutory authorities.
Given the large proportion of private land in the Coastal Plains area and the scattered small conservation reserves, biodiversity conservation will rely heavily on the owners and managers of private land and the network of road and rail reserves and other public land.
The inclusion of biodiversity protection in revised Planning Schemes is being pursued with Shires as is vegetation mapping and management on roadsides. Shires are encouraged to consult with NRE in relation to environmental significance and vegetation protection. Roadside management plans have been prepared for some municipalities (e.g. Mornington Peninsula) Western Port roadsides, the Bellarine Peninsula and the Great Ocean Road (by VicRoads).
Interest in implementing conservation programs (such as Land for Wildlife) among private landholders is increasing. These will concentrate on protecting native vegetation, threatened species, communities and critical habitats. Landholder groups are encouraged and provided with assistance to prepare project bids such as with the Natural Heritage Trust program.
Control of introduced predators will continue to be a high priority. The impact of predators on some species is well established however their impact on a suite of other species is less clear and is a priority for current research so that effective control programs can be developed and implemented. Cooperation with landholders is especially important in predator control and existing programs will be enhanced to maximise benefits both to stock and native fauna.
Liaison also occurs with other government departments and community groups for the development of fire management plans which integrate the use and prevention of fire for biodiversity conservation and other purposes.
Together with the state-wide key directions outlined earlier, land and water managers and planners in each bioregion should consider the following priorities.
- Extend the coverage of Roadside Conservation Management Plans particularly in the Otway Plain and the eastern part of the Warrnambool Plain.
- Determine and implement ecologically based fire regimes in heathland habitats as part of integrated processes outlined in the Code of Practice for Fire Management.
- Protect grassland and grassy woodland sites, especially on the Gippsland Plain and South Gippsland.
- Identify sites of biological significance in conjunction with local government and land holders and encourage appropriate use of this information in local planning schemes, including recognition of appropriate areas for subdivision that have minimal biodiversity impacts.
- Focus management efforts on depleted ecological vegetation classes with an emphasis on sites with the best possibilities of long-term viability and cost-effectiveness.
- Support ‘Friends Groups’ in urban areas to actively manage significant sites on a priority basis, particularly along the coast.
- Minimise the impact of pets on native fauna, particularly in the urban fringe areas, by raising awareness and by encouraging responsible pet management.
- Protect remnant Red Gum sites in the Otway Plain.