The Forrestdale and Thomsons Lakes Ramsar Site comprises two separate nature reserve

Nature reserve

A nature reserve is a protected area of importance for wildlife, flora, fauna or features of geological or other special interest, which is reserved and managed for conservation and to provide special opportunities for study or research...

s, totaling 754 ha in area, protecting two shallow fresh

Freshwater

Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

 to brackish

Brackish water

Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"...

, seasonal lakes in a suburban and agricultural landscape in south-western Western Australia

Western Australia

Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

. It is used mainly for birdwatching

Birdwatching

Birdwatching or birding is the observation of birds as a recreational activity. It can be done with the naked eye, through a visual enhancement device like binoculars and telescopes, or by listening for bird sounds. Birding often involves a significant auditory component, as many bird species are...

 and walking

Walking

Walking is one of the main gaits of locomotion among legged animals, and is typically slower than running and other gaits. Walking is defined by an 'inverted pendulum' gait in which the body vaults over the stiff limb or limbs with each step...

. It lies in the Swan Coastal Plain

Swan Coastal Plain

The Swan Coastal Plain in Western Australia is the geographic feature which contains the Swan River as it travels west to the Indian Ocean. The coastal plain continues well beyond the boundaries of the Swan River and its tributaries, as a geological and biological zone, one of Western Australia's...

 bioregion

Ecoregion

An ecoregion , sometimes called a bioregion, is an ecologically and geographically defined area that is smaller than an ecozone and larger than an ecosystem. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural...

. The site is recognised as being of international importance under the Ramsar Convention on Wetlands

Ramsar Convention

The Ramsar Convention is an international treaty for the conservation and sustainable utilization of wetlands, i.e., to stem the progressive encroachment on and loss of wetlands now and in the future, recognizing the fundamental ecological functions of wetlands and their economic, cultural,...

, under which it was designated Ramsar Site 481 on 7 June 1990.

Description

Forrestdale Lake

Forrestdale Lake

Forrestdale Lake is a lake nature reserve in the City of Armadale, Western Australia, approximately 25 km south of the central business district of Perth, the state capital, and on the southern fringes of the Perth metropolitan area. It lies immediately south of the suburb of Forrestdale, and 8 km...

 and Thomsons Lake

Thomsons Lake

Thomsons Lake is a lake nature reserve in the City of Cockburn, Western Australia, approximately 25 km south of the central business district of Perth, the state capital, and on the southern fringes of the Perth metropolitan area. It in the suburb of Beeliar, 7 km south-west of Jandakot Airport...

 lie 10 km apart within the southern Perth

Perth, Western Australia

Perth is the capital and largest city of the Australian state of Western Australia and the fourth most populous city in Australia. The Perth metropolitan area has an estimated population of almost 1,700,000....

 metropolitan area. They are similar in size and shape, being oval, about 1.6 km long by 1.3 km wide, with large central areas of open water when full and with shorelines vegetated with concentric fringes of the introduced bulrush

Typha

Typha is a genus of about eleven species of monocotyledonous flowering plants in the family Typhaceae. The genus has a largely Northern Hemisphere distribution, but is essentially cosmopolitan, being found in a variety of wetland habitats...

 Typha orientalis, sedges

Cyperaceae

Cyperaceae are a family of monocotyledonous graminoid flowering plants known as sedges, which superficially resemble grasses or rushes. The family is large, with some 5,500 species described in about 109 genera. These species are widely distributed, with the centers of diversity for the group...

, paperbarks

Melaleuca

Melaleuca is a genus of plants in the myrtle family Myrtaceae known for its natural soothing and cleansing properties. There are well over 200 recognised species, most of which are endemic to Australia...

 and other plants tolerant of seasonal waterlogging. Both lakes usually dry out in summer, though Thomsons lake may occasionally retain water throughout the year. Both reserves contain areas of native woodland

Woodland

Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...

. They are the best remaining examples of brackish, seasonal lakes with extensive fringing sedgeland typical of the Swan Coastal Plain. Regionally they form a major breeding, migration stop-over and semi-permanent drought refuge

Drought refuge

A drought refuge is a site that provides permanent fresh water or moist conditions for plants and animals, acting as a refuge habitat when surrounding areas are affected by drought and allowing ecosystems and core species populations to survive until the drought breaks...

 area for shorebirds

Wader

Waders, called shorebirds in North America , are members of the order Charadriiformes, excluding the more marine web-footed seabird groups. The latter are the skuas , gulls , terns , skimmers , and auks...

 and other waterbirds.

Ramsar criteria satisfied by the site are that it:

• contains a representative, rare, or unique example of a natural or near-natural wetland type found within the appropriate biogeographic region;
• supports populations of a plant and/or animal species important for maintaining the biological diversity of a particular biogeographic region;
• regularly supports 20,000 or more waterbirds; and
• regularly supports 1% of the individuals in a population of one species or subspecies of waterbird.

Conservation

Conservation management of the site focuses on:

• maintenance of water quality since nutrient levels in the lakes are fairly high, and water levels may be affected by groundwater
  Groundwater
  Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...
  
   extraction for domestic and agricultural purposes, or increased drainage discharge from nearby urban areas;
• preventing the spread of Typha orientalis throughout the lakes;
• the need to control chironomid
  Chironomidae
  Chironomidae are a family of nematoceran flies with a global distribution. They are closely related to the Ceratopogonidae, Simuliidae, and Thaumaleidae...
  
  numbers because of their nuisance factor to nearby residents; and
• mitigating further deterioration of wetland and woodland vegetation resulting from over-use by visitors.