Australian Wetlands Database

Ramsar wetlands

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Muir - Byenup System

Overview

Key facts and figures:

Date of listing:

05 January 2001

The Ramsar site comprises a suite of partly inter-connected lakes and swamps of varying size,  Photo: Jennifer Higbid

Australian Ramsar site number:

56

Criteria: 

2, 4, 5, 6

State/Territory:

Western Australia

Area:

10631hectares (of which approximately 7000hectares is wetland)

Drainage Division or IMCRA  region:

South-West Coast

Wetland type: 

  • O - Permanent freshwater lakes (over 8 ha); includes large oxbow lakes
  • R - Seasonal/intermittent saline/brackish/alkaline lakes and flats
  • Tp - Permanent freshwater marshes/pools; ponds (below 8 ha), marshes and swamps on inorganic soils; with emergent vegetation water-logged for at least most of the growing season
  • Ts - Seasonal/intermittent freshwater marshes/pools on inorganic soils; includes sloughs, potholes, seasonally flooded meadows, sedge marshes
  • U - Non-forested peatlands; includes shrub or open bogs, swamps, fens
  • W - Shrub-dominated wetlands; shrub swamps, shrub-dominated freshwater marshes, shrub carr, alder thicket on inorganic soils
  • Xf - Freshwater, tree-dominated wetlands; includes freshwater swamp forests, seasonally flooded forests, wooded swamps on inorganic soils

Key features of the site:

The Muir-Byenup System Ramsar site is located inland 55 km south-east of the town of Manjimup in south-west Western Australia. The Ramsar site comprises a suite of partly inter-connected lakes and swamps in an internally draining catchment. The wetlands are varied in size, salinity (saline to fresh), permanence (seasonal to permanent) and substrate (peat and inorganic).

The Ramsar wetland includes Lake Muir, Byenup Lagoon, Tordit-Gurrup Lagoon, Poorginup Swamp, Neeranup Swamp, Coorimup Swamp and Wimbalup Swamp and reserves in the surrounding area.

Lake Muir is fringed by sedgelands, low samphire shrubland and Melaleuca dominated wetland scrub. The rest of the wetlands on the site are fringed by sedgelands, and Melaleuca, Astartea and Agonis shrublands. Eucalypts, such as Jarrah and Yate, dominate higher elevations.

The site has a rich diversity of plants for such a small area, with over 600 native plant species recorded. This diversity may be due to the wide range of complexes of soil types and hydrological patterns found over short distances on the site. Three nationally vulnerable wetland-dependent orchids, the Harrington's Spider-orchid, Christine's Spider Orchid and Tall Donkey Orchid, also occur in the site.

The Muir-Byenup System Ramsar site supports a large number and diversity of waterbirds, with more than 50 waterbird species recorded. Lake Muir is a migration stop-over site for shorebirds such as the Red-necked Stint. The open lakes are used for moulting by thousands of Australian Shelduck and as a drought refuge by large numbers of waterbirds. The Little Bittern, Spotless Crake, Australasian Bittern, Black Swan, Eurasian Coot and Silver Gull all breed at the site.

Seven native fish species have been recorded in the site including the nationally vulnerable Balston's Pygmy Perch.

The site is located within a series of reserves for water and conservation of flora and fauna. The bird observatory on Muir Highway provides facilities for nature-based recreation such as bird watching. The wetlands are spiritually significant for the Noongar people.

Justification of the listing criteria:

The Muir-Byenup System Ramsar site meets four of the nine criteria:

Criterion 2: The Muir-Byenup System Ramsar site contains reasonable populations of three nationally vulnerable wetland-dependent orchids; Harrington's Spider-orchid, Christine's Spider Orchid and Tall Donkey Orchid. These plants mainly occur on seasonally inundated areas or wetland margins, which have been extensively cleared for agriculture elsewhere in south-western Australia. The site also supports the nationally vulnerable Balston's Pygmy Perch.

Criterion 4: The Muir-Byenup System Ramsar site is one of the most important moulting sites for Australian Shelducks in south-western Australia. The open lakes regularly support moulting by thousands of shelducks. Lake Muir is used as a drought refuge by tens of thousands of waterbirds. The Little Bittern, Spotless Crake, Australasian Bittern, Black Swan and Eurasian Coot all breed at the site.

Criterion 5: Up to 52,000 waterbirds have been counted at the Muir-Byenup System Ramsar site. The annual water depth of the site suggests conditions suitable for use by 20,000 waterbirds at least several times within a 25 year period.

Criterion 6: More than 1% of the south-western Australian population of the Australasian Bitterns occur regularly in the Muir-Byenup System Ramsar site and on occasion, use the sedge swamps of the site for breeding.

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.