2.3.3 Ecosystems


To deal with the complexity of a large number of diverse assets, a landscape classification approach was developed specifically for the bioregional assessment (BA) for the Hunter subregion to systematically class landscape features that are hydrologically and biologically similar or connected. Landscape classes were identified within five broad landscape groups: ‘Riverine’, ‘GDE’, ‘Coastal lakes and estuaries’, ‘Non-GDE vegetation’ and ‘Economic land use’.

Four riverine landscape classes were defined based on hydrology and river bed substrate. Ephemeral streams (11,000 km) form the dominant ecohydrological class with 1900 km of perennial streams, 1200 km of moderately to highly intermittent streams and 800 km of lowly to moderately intermittent streams.

Nine landscape classes within the ‘GDE’ landscape group were defined based on vegetation formations (grassy woodlands, heathlands, semi-arid woodlands, rainforest, forested wetland, freshwater wetland, wet sclerophyll forest and dry sclerophyll forest) in addition to springs. The total area identified as groundwater-dependent ecosystems (GDEs) was 358 km2.

A little over 10,400 km2 of native vegetation within the preliminary assessment extent (PAE) of the Hunter subregion is not classified as GDE. Both the mapping of vegetation and the nature of the water dependence of some identified GDEs is a significant source of uncertainty. The accuracy of landscape classes in the ‘GDE’ landscape group depends on the accuracy of vegetation mapping and remote sensing of groundwater dependence.

Seven landscape classes within the ‘Coastal lakes and estuaries’ landscape group were defined with the majority of the Hunter subregion falling within the ‘Lake’ and ‘Seagrass’ landscape classes. These totalled 263 km2.

Five landscape classes in the ‘Economic land use’ landscape group were defined (~6000 km2), dominated by ‘Dryland agriculture’ (3820 km2) and ‘Intensive use’ (1070 km2) landscape classes of the subregion.

Last updated:
18 January 2019