Deep freshwater marsh

Deep freshwater marshes are relatively permanent wetlands FLORA AND FAUNA that hold water year round. They are generally more than one Stands of River Red Gums or Lignum with metre deep and remain flooded for more than a year. However semi-terrestrial herbs and grasses (e.g. Spike they may dry out during drought years. Rushes) can occur on the edges of the marshes, Healthy deep freshwater marshes support a diverse range of specifically in temporary wet areas. flora and fauna, with plant zones relating to water level and Reed beds can develop where the water is deeper and more water level fluctuations. permanent. These beds can include Cane Grass, Common Reed, Deep freshwater marshes provide habitat and summer refuge Giant Rush, Cumbungi, Tall Spike Rush or species of Twig Rush. for animals when more temporary systems have dried out. They Shrubs, such as the Woolly Tea-tree or River Tea-tree, create are popular sites for bird watching as they function as animal dense shade beneath their canopies. refuges during periods of low rainfall. Examples of deep freshwater marshes are: • Waterway and Nerrin Nerrin Swamp (Nerrin Nerrin Wetlands) • Dergholm (Youpayang) Wetlands • Bryan’s Swamp and Mahoney Swamp (Southern Grampians) • Lake Muirhead (north of Glenthompson)

• Cumbungi is a good habitat for birds on the edge of wetlands

Many have areas of open water where underwater plant species, such as Ribbon Weed, Pond Weed and Stoneworts, provide habitat for invertebrates and fish, and food for birds. These different habitats are home to a variety of animals. Reeds and shrubs create shelter for birds, such as Lewins Rail, and nesting sites for Spoonbills and Ibis. Reeds are home to Reed Warblers, Moorhens and Bitterns. Open water attracts ducks, including the Musk, Blue-billed and rare Freckled Ducks. These feed on Pond Weed, Ribbon Weed and invertebrates. • Deep freshwater marsh

continues over page... THREATS Altered salinity regime Deep freshwater marshes are often made more permanent by Many deep freshwater marshes exist along the estuaries of water diversions from other wetlands. Other notable threats rivers and streams and are vulnerable to altered salinity are pest plants, unrestricted grazing and native vegetation regimes. When a river mouth is closed, saline water can enter clearance. marshes, resulting in higher salinity. The salt-water wedge common in many estuaries near their mouth can travel Altered water regime upstream if natural bars or barriers are breached. Species like the Woolly Tea-tree and Cumbungi can tolerate short periods of Sometimes the marshes are made deeper to improve habitat for saline water, but cannot survive long-term exposure to high particular waterbirds. This, along with more frequent flooding, salinity. can change the habitat for associated plants and animals. Water extraction for irrigation or stock watering also is a potential threat, since this can make marshes shallower and more temporary. The natural fluctuation of water levels in wetlands is an important feature of their cycle and is essential in maintaining plant diversity and biological health.

• Bryan’s Swamp (Southern Grampians)

For further information, please contact: Glenelg Hopkins CMA 79 French Street, Hamilton, Vic 3300 Tel: (03) 5571 2526 Fax: (03) 5571 2935 www.glenelg-hopkins.vic.gov.au

Photography: James Pevitt & Michelle Casanova GSDM7162 02/06