Rushy Lagoon - Cremorne

Habitat description and values:

Rushy Lagoon is a sedgey wetland, dominated by Baumea arthrophylla and B. juncea. The site also forms part of a landform known as a deflation basin.  A deflation basin is a topographic basin excavated by wind erosion, which removes unconsolidated material. This can be deposited on the downwind side as a low crescent shaped  (dunelike) mound termed a lunette. Deflation basins are typically circular or semi circular and occur in drier parts of the State. They formed during more arid times in Tasmania most likely three to four thousand years ago and most now hold water continuously or for a period following rain.  The landform includes all of Rushy Lagoon and the lunette which occurs on the south-eastern fringe.

The wetland provides habitat for many birds, including several species which are rare or uncommon in Tasmania (the blue-billed duck, hardhead, Australasian shoveller, great egret, Australian spotted crake and black fronted dotterell.  Other birds recorded at the lagoon include the swamp harrier (recorded as breeding at the lagoon) and Australian bittern, which is rarely seen but widespread. The landowner has observed sea eagles hunting over the lagoon. The wetland also provides habitat for tiger snakes, eels and frogs.

Significance:

It has been estimated that less than half of Tasmania's wetlands remain in their natural condition and that 12% of wetlands have been severely disturbed (Kirkpatrick and Harwood, 1981).  Rushy Lagoon therefore is significant for nature conservation simply by the fact that it has survived in relatively natural condition until now.  In addition, it provides valuable habitat for many water birds (see "habitat description and natural values" and attached bird list) and other fauna.   

The wetland is also highly significant for its geomorphological values, as it is part of an extremely poorly reserved type of landform in Tasmania: a deflation basin and associated lunette.  These landforms are also significant because they can hold important scientific records of climatic change in recent geological time. They are fossil landforms (meaning that the primary reason for their being is not currently active) although if there was another major dry phase the process may restart which arguably makes them dormant. 

Rushy Lagoon is one of the few remaining large natural wetlands in a semi-urban area, and has high local significance.  Rushy Lagoon is also listed as a supplementary wetland of State Significance in the Directory of Important Wetlands in Australia (1996).

A large part of the lagoon was recently transferred to Crown ownership as a result of a subdivision on adjoining land.  This part of the lagoon is proposed to be declared a nature reserve under the National Parks and Wildlife Act 1970.  The location of the landowner's part of the lagoon immediately adjacent to a proposed nature reserve adds to its significance and the need to ensure consistent management of the whole wetland area.  It is also extremely desirable that other private landowners be encouraged to covenant the parts of the lagoon they own.  The Department of Primary Industries, Water and Environment intends to work with all landowners to achieve the best possible level of protection for the lagoon

Text received from Kim Sly, Scientific Office, Protected Areas on Private Land.

Any problems, please email webmaster. This page was last updated 24/07/2008