[5] Lake Muir is usually brackish (1000–3000 mg/L TDS) at the end of winter, saline by summer and dry throughout autumn.

[6] A 14-square-kilometre (5.4 sq mi) section of wetland around Lake Muir has been identified by BirdLife International as an Important Bird Area (IBA) because it provides habitat for 10 or more pairs of endangered Australasian bitterns.

The wetlands within the IBA are shallow with extensive beds of dense sedgeland and fringing stands of shrubland and woodland.

Lake Muir has been excluded from the IBA as it is unsuitable for bitterns but it has supported large numbers of Australian Shelduck and may prove to be globally significant for that species.

The Department of Environment and Conservation (CALM) started monitoring the wetlands system in 1980 in order to manage the duck shooting.