4.2 Natural assets

11: EcoLogical Australia Pty Ltd, 2019 12: NSW Government - Office of Water, 2009 13: MidCoast Council, 2020 14: Geosciences Australia, undated

Coastal wetlands are known as the kidneys of the landscape, filtering and attenuating pollutants to keep the estuary water clean. They are like sponges, soaking up floodwater and releasing it slowly, mitigating the impact of floods on the estuary. Mangroves stabilise shorelines. Coastal wetlands store carbon, helping to mitigate increases of greenhouse gases in the atmosphere. Coastal wetlands are biodiversity hotspots, providing habitat for migratory shorebirds and nursery habitat for many fish, crustaceans and molluscs, including species of commercial and recreational value. Wetlands also provide opportunities for naturebased tourism and have Aboriginal cultural significance, historical significance and importance for science and education.

While the majority of coastal wetlands in the Manning have been drained and modified, wetlands of considerable conservation significance still occur.11 These include: • Large areas of mangrove forest and brackish wetlands in areas such as Cattai Wetlands, Big Swamp and

Coopernook Swamp • Large wetlands at Dawson wetlands, Kundle Kundle and Manning Point • Crowdy Lagoon in Crowdy Bay National Park which is classified as a high priority Groundwater Dependent Ecosystem (GDE)12 and is listed as a nationally important wetland • Forested wetlands with swamp mahogany, broadleaved paperbark and swamp oak13 • Estuarine and near-shore marine systems made up of coastal mangroves, salt marshes and sea-grass beds which rely on the submarine discharge of groundwater14 • Seagrass meadows. A study conducted in Stage 2 of the ECMP mapped 13 types of coastal wetlands in the Manning including broad-leafed paperbark swamps, freshwater wetlands, reedlands, saltmarsh and grey mangrove forest (Annexure F: The Manning River ECMP Coastal Wetlands Mapping Report, Ecological 2019). The study found that:

• 69% of the remaining coastal wetlands are in good condition • 19% are in fair condition • 12% are in poor/very poor condition The majority (86%) of all wetland types mapped are identified and protected under State or Commonwealth legislation.

Photo: Coastal wetlands are the kidneys of the landscape

Freshwater wetlands contribute to base flow of the river.15 Some of these wetlands such as the alpine swamps in the Barrington Tops are high priority Groundwater Dependent Ecosystems.16 Groundwater aquifers are found throughout the Manning catchment.17 They make a significant contribution to baseflow in the river (Pers. Comm. Dr. Peter Serov, August 2019). Groundwater “commonly provides an important and reliable source of water to many ecosystems and can be the main factor controlling the distribution of ecosystem types” (Geoscience Australia). Up-river alluvial aquifers and coastal sand

15: Midcoast Water, 2011 16: NSW Government - Office of Water, 2009 17: Commonwealth of Australia, 2017-18 18: Betterridge & Rabbidge, 2016 19: Swanson, 2020 aquifers have significant connectivity to surface water.18 Understanding the connection between groundwater and surface water is important when regulating groundwater use, recognising that drawdown of the aquifer influences surface water flows. Groundwater Dependent Ecosystems are ecosystems that depend on groundwater for some or all their water requirements. Coastal wetlands and estuarine and near-shore marine systems such as coastal mangroves, salt marshes and sea-grass beds in the Manning River Estuary are classified as Groundwater Dependent Ecosystems, as they rely on the submarine discharge of groundwater (Geoscience Australia). Healthy in-stream condition contributes to conservation of aquatic fauna such as the Platypus and Manning River Helmeted Turtle, and the productivity of fisheries including commercial species. Water sources with high instream value in the Manning Catchment include sections of the Upper, Mid and Lower Manning; Upper and Lower Gloucester and Barrington; Upper Barnard, Bowman and Nowendoc Rivers (NSW Govt. 2016 p. 12-14). Riparian vegetation plays a central role in stabilising waterways, reducing channel boundary erosion, filtering diffuse-source run-off and providing habitat. Riparian vegetation helps maintain water quality by reducing the amount of pollutants entering the waterway. It serves as a physical buffer, slowing down overland flow and mitigating the negative impacts of flooding.19 All of these ecosystem services benefit the estuary.

Vegetated riparian areas are also very important for biological connectivity. Intact and connected riparian vegetation provides dispersion corridors for wildlife and sequesters carbon, mitigating the impact of climate change. Managing riparian vegetation is a primary tool for catchment-scale improvements.20 Terrestrial vegetation has an important role to play in soil organics, erosion control, providing shade for livestock away from watercourses, driving the local water cycle and hydrating the landscape. It will be managed through Council’s Biodiversity Framework. Rivers, riparian zones and estuaries are exceptionally biodiverse because they form transition zones between aquatic and terrestrial ecosystems. MidCoast Council’s draft Biodiversity Framework provides a full listing of biodiversity assets and management strategies in the Manning region. The focus for the ECMP is on aquatic and riparian fauna, particularly listed threatened species within the Planning Area. These include:

• The endangered (NSW) Manning River helmeted turtle whose entire known range is confined to the

Manning catchment • The iconic platypus reported to be nearing threatened-species status21 • A maternity camp of vulnerable grey-headed flying fox in a patch of Sub-tropical Lowland Rainforest (EEC) at Wingham Brush. Flying foxes are keystone pollinators of over 50 native tree species and are critical to the survival of riparian vegetation • At least twenty-five species of fish in the freshwater reaches22. Migratory fish play a critical role in keeping our rivers, wetlands and oceans healthy by supporting a complex food web. Populations are declining globally.23 Freshwater refuge pools play a critical role in supporting local and regional biodiversity. Deep freshwater pools and springs are home to an array of fauna, forming biodiversity hotspots. Aquatic wildlife species retreat to, persist in and expand from refuge pools under changing environmental conditions.24 Around 18.5% of the Manning River estuary and catchment is protected in the National Park estate. Subcatchments with the highest levels of protection are the middle Barnard River, Myall Creek, Barrington and Rowley’s Rivers. Lower levels of protection through conservation reserves can be seen in the middle Manning River and Burrell, Bakers and Belbora Creeks which have no reservation. Cedar Party Creek and Bowman River also have very low percentages of reserved land. Figure 15 shows the percentage of reservation for each of the subcatchments in the Manning valley.

“The remaining native vegetation remnants are very important – we need to improve and maintain them.”

Noel Piercy, Member, ECMP Reference group

20: Pietsch, Daley, Stout, & Brooks, 2019 21: University of New South Wales, 2020 22: Bishop, 2016 23: World Fish Migration Foundation, 2020 24: Keppel et al, 2011 Turtle photo courtesy of Gary Stephenson.