Australian Wetlands Database

Ramsar wetlands

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Vasse-Wonnerup System

Overview

Key facts and figures:

Date of listing:

07 June 1990

The estuary of the Vasse-Wonnerup System (2009),  Photo: GeoCatch

Australian Ramsar site number:

38

Criteria: 

5, 6

State/Territory:

Western Australia

Area:

1115 hectares

Drainage Division or IMCRA  region:

South-West Coast

Wetland type: 

  • J - Coastal brackish/saline lagoons; brackish to saline lagoons with at least one relatively narrow connection to the sea
  • N - Seasonal/intermittent/irregular rivers/streams/creeks
  • Ss - Seasonal/intermittent saline/brackish/alkaline marshes/pools
  • Xf - Freshwater, tree-dominated wetlands; includes freshwater swamp forests, seasonally flooded forests, wooded swamps on inorganic soils

Key features of the site:

The Vasse-Wonnerup System Ramsar wetland is situated in the Perth Basin, south-western Western Australia. It is an extensive, shallow, nutrient-enriched wetland system of highly varied salinities. Large areas of the wetland dry out in late summer.

The site is located on a narrow, flat plain separated from the ocean by a narrow system of low dunes. The system is comprised of two former estuaries - the Vasse and Wonnerup Lagoons, with inflows of seawater managed by floodgates (weirs) since early 1900s. Water in the Vasse-Wonnerup System is fresh in winter and becomes saline in summer due to leakage past the floodgates and, since 1988, some seawater being allowed to enter.

Vasse-Wonnerup System is fringed by samphire and rushes with some melaleuca woodlands on higher ground. The Tuart Forest National Park component of the site is dominated by open-forest of mature Tuart trees and Western Australian Peppermint trees. Tree hollows in these areas provide important breeding sites for Australian Wood Duck, Australian Shelduck and possibly other duck species. The native Water Rat has been recorded in the Vasse-Wonnerup System at several locations.

The Vasse-Wonnerup System supports tens of thousands of resident and migrant waterbirds of a wide variety of species. More than 80 species of waterbird have been recorded in the System such as Red-necked Avocets and Black-winged Stilts, Wood Sandpiper, Sharp-tailed Sandpiper, Long-toed Stint, Curlew Sandpiper and Common Greenshank. Thirteen waterbird species are also known to breed at the Ramsar site, including the largest regular breeding colony of Black Swans in south-western Australia.

The Sabina and Abba Rivers of the Ramsar site are important indigenous cultural heritage sites and the Ramsar site would have traditionally been used by indigenous people of the area. Other items of heritage value include the 1927 floodgates on the Vasse and Wonnerup Estuaries outlet channels.

The urban area of Busselton, including a large canal estate residential subdivision, currently surrounds much of the Vasse Estuary. The Ramsar site is used mostly for conservation, nature-based activities, residential areas, farming and tourism.

Justification of the listing criteria:

The Vasse-Wonnerup Ramsar wetland meets two of the nine criteria:

Criterion 5: More than 33,000 waterbirds have been counted at the Vasse-Wonnerup System. Waterbird data indicate that more than 20,000 waterbirds use the Ramsar site each year, suggesting that the wetland regularly supports 20,000 waterfowl. This includes species such as Red-necked Avocets and Black-winged Stilts, Wood Sandpiper, Sharp-tailed Sandpiper, Long-toed Stint, Curlew Sandpiper and Common Greenshank.

Criterion 6: At least 1% of the Australian population of Black-winged Stilt and at least 1% of the world population of Red-necked Avocet use Vasse-Wonnerup System in most years.

Please see the More Information page for additional information on this Ramsar site and access to the Ramsar Information sheets and other associated site documents.