Key estuarine vegetation communities
The Hawkesbury’s riparian vegetation between Wisemans Ferry and Brooklyn is dominated by vegetation communities made up of Casuarina glauca (Swamp Oak), Eucalyptus robusta (Swamp Mahogany), Eucalyptus tereticornis (Forest Red Gum), Phragmites australis (Common Reed), Melaleuca linariifolia (Narrow-leaved Paperbark) and Melaleuca quiquenervia (Broad-leaved Paperbark). The transition from freshwater to estuarine vegetation communities occurs near Wiseman’s Ferry, where isolated patches of Aegiceras corniculatum (River Mangrove) are present. Fringing stands of the two predominant mangrove species, River and Grey Mangrove (Avicennia marina), become more abundant as you travel downstream from Laughtondale. There are significant areas of wetlands and saltmarsh communities present between Wiseman Ferry and Spencer.
Macrophytes are aquatic flowering plants, that often grow fully submerged (under water) by attaching to the sediments of wetlands and estuaries. Our key macrophyte groups in the Hawkesbury are mangroves, saltmarsh and seagrasses. Mapping of macrophytes have been undertaken by NSW Department of Primary Industries (DPI). Latest maps showing the spatial extent of each macrophyte type can be viewed on the Fisheries portal.
Wetlands are distinct ecosystems that get flooded by water, either permanently (for years or decades) or seasonally (for weeks or months). Wetlands are considered among the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal species. The water in wetlands is either freshwater, brackish or saltwater. The main wetland types are classified based on the dominant plants and/or the source of the water. For example, marshes are wetlands dominated by emergent vegetation such as reeds and sedges.
Wetlands are also known for their ecosystem services that include water purification, groundwater replenishment, stabilisation of shorelines and storm protection, water storage and flood control, and the processing of carbon (carbon fixation, decomposition and sequestration), other nutrients and pollutants. Learn more about a Council managed freshwater wetland in the next section below.