Places

General

Milyu in South Perth, Alfred Cove in Melville and Pelican Point in Crawley provide important habitat for many species of local and migratory birds, including trans-equatorial wading birds from as far away as Siberia. Waders and water birds move between the three Reserves on a daily basis – their sandbanks, mud-flats and beaches providing the only remaining significant feeding, nesting and resting areas in the Swan River Estuary.

The Estuary

Known also as the Derbarl Yerrigan, the Swan River Estuary has been a place of iconic importance to both the Noongar Aboriginal people who first populated its banks and to subsequent migrants who have settled along its reaches, providing not only for such requirements as food, water and transport, but also bringing a spiritual dimension to their lives.

Location

Forming the backdrop to the city of Perth, Western Australia, the Swan River Estuary extends approximately 60km from Fremantle to Ellen Brook, and 6km up the Canning River to Kent Street Weir. Its waters pass through the Swan Coastal Plain, the Guilford Formation, and the Bassendean, Spearwood and Quindalup Dunes, each major landform unit having its own specific vegetation communities populating the Estuary’s banks. Shallow sills of soil and mud divide the Estuary into three main sections: the Upper, Middle and Lower Estuaries. Essentially, the Upper Estuary is up-stream from Heirisson Island, the Middle Estuary encompasses Melville Water and the Lower Estuary is downstream from Point Walter.


Landsat imagery of Perth provided by Australian Centre for Remote Sensing (ACRES), Geoscience Australia, Canberra and digitally enhanced by Landgate (Western Australian Land Information Authority)

The Reserves

The Swan River Estuary provides grace and beauty to the city of Perth and its surrounding suburbs, extending approximately 60km from Fremantle to Ellen Brook, and 6km up the Canning River to Kent Street Weir. It is central to our way of life.

The original vegetation that once fringed its waters was unique and diverse, and included Samphire flats, Juncus kraussii sedgelands, forests of paperbark (Melaleuca rhaphiophylla) and flooded gum (Eucalyptus rudis), and stands of river sheoak (Casuarina obesa). It provided habitat for many species of waterbirds and land birds, including migratory wading birds. The fringing vegetation also protected the Estuary margins, reducing erosion and filtering nutrients and pollutants flowing into the river.

There is now very little surviving of this natural environment.

The removal of the rocky bar across the entrance to construct the Port of Fremantle has increased the marine influence. The dredging of channels has changed circulation patterns and altered chemical and biological processes. Fringing vegetation has been cleared for housing, industrial development, transport and recreation. The inappropriate dumping of rubbish and use of fertilizers in farming areas within the catchment and on urban gardens have left the Swan River Estuary in a highly stressed condition, with toxic pollutants and a proliferation of algal blooms. A decreasing rainfall pattern and the effects of Climate Change will also impact on the future health of the Estuary and the fauna it supports, causing significant community concern.

This concern, and a better understanding of the importance of fringing vegetation to the health of the Estuary, has been translated into state and local government agencies and community groups undertaking restoration projects to redress negative human impacts and to restore natural aesthetic values.

In 1990 the community set aside three relatively small but very important areas of vegetation and adjacent river shallows as the Swan Estuary Marine Park, which includes the A-Class Reserves of Alfred Cove (8.7ha), Pelican Point (5.5ha) and Milyu (4.4ha). They have been established "to maintain and restore the natural environment, and to protect, care for and promote the study of indigenous flora and fauna and to preserve any features of archeological, historic or scientific interest". Together they provide sanctuary to native fauna –particularly bird-life – which use each Reserve on a daily basis for foraging, breeding and roosting, depending on weather and tidal conditions.

It is the aim of the Swan Estuary Reserves Action Group Inc. to promote the ecological health and well-being of these Reserves and the fauna they support.

Fauna

A huge variety of local and migratory birdlife is supported by the Swan Estuary Marine Park and the adjacent A-Class Reserves.

Waders, shore birds and bush birds rely heavily on the habitat provided for feeding, breeding or resting.

Please refer to the guides and bird lists complied by Birds Australia Western Australia for further information.

Unfortunately, due mainly to habitat loss, a number of the species which were once abundant are now threatened. This increases the importance of maintaining the ecological health of remaining areas.

Many small mammals such as the southern brown bandicoot (Isoodon obesulus) and the brushtail possum (Trichosurus vulpecula) have disappeared - replaced by feral cats, foxes and rabbits; however in recent times, evidence of the lovely little Rakali  or Australian Water-rat ( Hydromys chrysogaster) has been found. Because rakali rely on a good supply of invertebrates, their presence is considered to be an encouraging indicator of good riverine health.

River dolphin use the adjacent waters, and a variety of fish species - including the yellow-eye mullet (Aldrichella forsteri) and cobbler (Cnidoglanis macrocephalis) - and prawns use the shallows and sea-grasses as both a juvenile nursery and feeding ground.

Other aquatic fauna include molluscs, polychaetes and crustaceans.


Ospey with cobbler at Milyu (Photo courtesy Tyron Miley)

Vegetation

Although little of it remains, natural vegetation along the margins of the Swan River Estuary is both unique and diverse, varying significantly with soil-types and other physical considerations. Vegetation in the three A-Class Reserves includes marshes, samphire flats, sedge-banks and areas of woodland and shrubland.

Principal among the upper-storey species is Eucalyptus rudis; while Melaleuca rhaphiophylla and Melaleuca cuticularis with Casuarina obesa form a middle storey, and Juncus kraussii the main species of sedge.

Samphire forms a low shrub community that includes species such as Sarcocornia blackiana and Suaeda australis.


Melaleuca curicularis at Pelican Point (Photo courtesy Margaret Matassa)

Each of the Reserves suffers extensively from weed infestations, such as Ferraria crispa (black flag) in Milyu; Schinus Terebinthifolius (Brazillian pepper tree), Typha orientalis (bulrush) and Pennisetum clandestinum (kikuyu grass) in Alfred Cove, and Leptospermum laevigatum (Victorian tea tree) in Pelican Point.

In the Marine Park, seagrass meadows help stabilise the river floor and provide an important food source and habitat for hundreds of marine animals, including a nursery habitat for fish and crustaceans, as well as a carbon sink. The seagrass (Halophilia ovalis) is a vital component in the ecology of the Estuary.

Community Concern

European settlement has had an irrevocable impact on the Swan River Estuary and its surrounding landscape.  Regional agricultural and urban industrial and housing development activities have introduced various nutrients and pollutants into the River, severely diminished the quality of river water. The banks of the Swan and Canning Rivers are still being cleared of native vegetation for dwellings and by those seeking river views, for transport systems and for a variety of recreation activities.

These, together with the emerging impacts of climate change and a rapidly increasing population, have given cause to an Estuary in crisis, with impacts not only affecting the human population, but also native flora and fauna, with fish species and birdlife diminishing rapidly.

Community concern over the health of the Estuary has been steadily growing and has seen the proclamation of the Swan River Conservation Act in 1958 and the establishment of the Swan River Conservation Board, which later became the Swan River Trust. In the Middle Estuary, three small A-Class Reserves (Milyu, Pelican Point and Alfred Cove) have been set aside as sanctuaries for birdlife; while the Swan Estuary Marine Park was established in 1999.

A number of local community groups have also emerged to do what they can to preserve the ecological integrity of the estuarine system. The Swan Estuary Reserves Action Group Inc. is one such volunteer organisation.