Aquatic species and communities

The IBRA Karuah-Manning and adjacent subregions support large areas of significant wetlands, coastal sand heaths and woodlands (DECCW, 2009). Major rivers in the IBRA Karuah-Manning subregion include the Manning, Gloucester and Karuah rivers (see Section 1.1.5). The tributaries of the Manning River rise immediately north of the Barrington Tops at an altitude of more than 1400 m above sea level. It is fed from the south by the Barrington, Gloucester and Avon rivers which flow through and drain the northern parts of the Gloucester subregion.

The Karuah River drains south from the lower slopes (600 m above sea level) of the Barrington Tops, past the Karuah National Park and into the north-western corner of the Port Stephens estuary (DECCW, 2010b). The Karuah River is also fed by the Wards and Mammy Johnsons rivers which also flow through the subregion. Together these rivers drain the southern parts of the subregion. The Port Stephens estuary supports 22 migratory and ten breeding shorebird species. Two endangered and eight vulnerable shorebird species listed under the TSC Act have been recorded at Port Stephens. The estuary, together with rivers, creeks and tributaries under tidal influence, are included in the Port Stephens-Great Lakes Marine Park. The estuaries of the NNC are dominated by mangrove communities composed of Avicennia marina, Aegiceras coniculatum, Exoecaria agallocha and saltmarsh species. Vegetation on freshwater margins consists of swamp oak (Casuarina glauca) and paperbark (Melaleuca quinquenervia) and flooded gum (Eucalyptus grandis) is prevalent on alluvial river flats.

The NSW Office of Water and the NSW Office of Environment and Heritage have used a risk analysis framework (Serov et al., 2012) to identify groundwater-dependent ecosystems overlying New South Wales coastal groundwater sources. The conceptual framework classifies groundwater-dependent ecosystems based on the degree on which they depend on groundwater access and their priority for management actions. It allows potential and actual impacts of proposed activities on groundwater dependent ecosystems to be assessed in accordance with the Water Management Act 2000 (NSW) and other relevant legislation. The Gloucester subregion contains no groundwater dependent ecosystems identified within this framework. One wetland has been identified in proximity to the subregion (Figure 34) (Wallaroo wetlands about 4 km north-west by west of Karuah) along with several karst wetlands.

The water sharing plan (WSP) for the Lower North Coast area covers the Manning Extraction Management Unit (State of NSW through the Department of Water and Energy, 2009). Within this Unit, the Upper Gloucester River Management Zone lies within the section of the Gloucester subregion north of Craven, and covers the Avon and Upper Gloucester rivers, amongst others. The section of the subregion south of Craven is covered by a separate WSP for the Karuah River Water Source (DIPNR, 2004), which covers the Karuah, Mammy Johnsons and Wards rivers, amongst others. The WSP for the Lower North Coast area identifies six species of endangered frogs and two species of endangered birds in the Lower Barrington/Gloucester and Gloucester Water Sources; four species of endangered frog and one species of endangered bird in the Avon Water Source; and four species of endangered frog and two species of endangered birds in the Central and Lower Karuah Water Sources.

Figure 34

Figure 34 Distribution of groundwater-dependent ecosystems adjacent to the Gloucester subregion

Last updated:
5 January 2018