1.3.2.1 Description


This section describes the ecological assets in the asset list that were considered to be water dependent. Of the 1272 ecological assets in the asset list, 1131 were deemed to be water dependent for the purposes of the BA. The water-dependent asset register contains 599 assets in the ‘Vegetation’ subgroup, 12 in the ‘Groundwater feature’ subgroup and 520 in the ‘Surface water feature’ subgroup. A more detailed summary of the distribution of assets according to asset class in the asset list is presented in Table 7.

Table 7 Summary of ecological assets within the Gwydir subregion


Subgroup

Asset class

Not in water-dependent asset register

In water-dependent asset register

Total assets (asset list)

Groundwater feature (subsurface)

Aquifer, geological feature, alluvium or stratum

0

12

12

Groundwater total

0

12

12

Surface water feature

Floodplain

0

36

36

Lake, reservoir, lagoon or estuary

0

12

12

Marsh, sedgeland, bog, spring or soak

0

14

14

River or stream reach, tributary, anabranch or bend

0

299

299

Waterhole, pool, rockpool or billabong

0

56

56

Wetland, wetland complex or swamp

0

103

103

Surface water total

0

520

520

Vegetation

Groundwater-dependent ecosystem

126

249

375

Habitat (potential species distribution)

15

350

365

Vegetation total

141

599

740

Total

141

1131

1272

Data: Bioregional Assessment Programme (Dataset 1)

1.3.2.1.1 Groundwater features

All 12 assets listed in the ‘Groundwater feature (subsurface)’ subgroup were ‘assumed to be water dependent’ and included in the water-dependent asset register for further consideration during the assessment (Table 7). The majority of these groundwater features were aquifers identified in the Water Asset Information Tool (WAIT) database for the Gwydir subregion (Australian Government Department of the Environment, Dataset 2). Three assets were identified as Great Artesian Basin (GAB) recharge areas (Geoscience Australia, Dataset 3) and these are located throughout the eastern part of the subregion (Figure 4).

1.3.2.1.2 Surface water features

All 520 assets listed in the ‘Surface water feature’ subgroup were assumed to be water dependent (Table 7). The main area coverage within the ‘Surface water feature’ subgroup are ‘Floodplain’ and ‘Wetland, wetland complex and swamp’, and these are mostly in the western and north-western parts of the subregion (Figure 4).

Figure 4

Figure 4 Surface water features and Great Artesian Basin recharge areas in the Gwydir subregion

Some assets are represented multiple times within the asset register. These replicates are retained in each of the overlapping asset databases as boundaries may differ between databases, and to ensure they are assessed separately by each relevant BA and to enable future assessments to potentially aggregate assessment results for the replicated assets across more than one subregion. For example, the Gwydir wetlands, shown as ‘Wetland, wetland complex or swamp’, are also classified as ‘Floodplain’ and ‘Marsh, sedgeland, bog, spring or soak’.

‘River or stream reach, tributary, anabranch or bend’ polygons are not shown in the map as they cover the entire subregion.

Data: Bioregional Assessment Programme (Dataset 1); Australian Government Department of the Environment (Dataset 2, Dataset 6, Dataset 7, Dataset 9); Geoscience Australia (Dataset 3); NSW Department of Environment, Climate Change and Water (DECCW) (Dataset 4); Office of Environment and Heritage (OEH) NSW (Dataset 5); Murray-Darling Basin Authority (Dataset 8)

1.3.2.1.3 Vegetation

Assets listed in the ‘Vegetation’ subgroup consist of two classes: ‘Groundwater-dependent ecosystem’ or ‘Habitat (potential species distribution)’.

Groundwater-dependent ecosystems

All 375 assets identified as groundwater-dependent ecosystems were sourced from the National atlas of groundwater dependent ecosystems (GDE Atlas; Bureau of Meteorology, Dataset 10). A breakdown of the ecological assets identified as being dependent on the surface water expression of groundwater and the subsurface water expression of groundwater is given in Table 8 and their spatial distribution is shown in Figure 5 and Figure 6 respectively. Approximately 34% of the assets were excluded from the water-dependent asset register because they were deemed to have a low likelihood of dependence on either surface or subsurface presence of groundwater (Table 8).

Table 8 Breakdown of groundwater-dependent ecological assets in the ‘Vegetation’ subgroup for the Gwydir subregion


Subgroup

Asset class

Dependency

Not in water-dependent asset register

In water-dependent asset register

Vegetation

Groundwater-dependent ecosystem

Dependent on surface expression of groundwater

19

66

Dependent on subsurface presence of groundwater

107

183

Total

126

249

Data: Bioregional Assessment Programme (Dataset 1)

Figure 5

Figure 5 Groundwater-dependent ecosystems that rely on the surface expression of groundwater including surface water channels (surface line features) and vegetation communities (surface area features)

Data: Bioregional Assessment Programme (Dataset 1), Bureau of Meteorology (Dataset 10)

Figure 6

Figure 6 Groundwater-dependent ecosystems that rely on the subsurface presence of groundwater

Data: Bioregional Assessment Programme (Dataset 1), Bureau of Meteorology (Dataset 10)

Habitat (potential species distribution)

Out of a total of 365 assets, 350 assets within the ‘Habitat (potential species distribution)’ asset class were considered to be water dependent (Table 7).

All assets in Collaborative Australian Protected Area Database (CAPAD) areas (Australian Government Department of the Environment, Dataset 11) and in Important Bird Areas (Birds Australia, Dataset 12) were deemed to be water dependent. Of the NSW Government assets, all assets derived from the NSW climate change corridors (Office of Environment and Heritage (OEH) NSW, Dataset 16), native vegetation management areas (NSW Department of Environment, Climate Change and Water (DECCW), Dataset 15), Travelling Stock Route Conservation Values (NSW Department of Environment, Climate Change and Water, Dataset 14), and Gwydir wetlands and floodplains vegetation data (Office of Environment and Heritage (OEH) NSW, Dataset 5) were deemed water dependent.

The remaining assets were either categorised as ‘Threatened ecological communities’, or ‘Habitat of threatened ecological species’.

Threatened ecological communities

Six communities listed under the EPBC Act occur in the Gwydir subregion, and all were deemed to be water dependent (Table 9). ‘White Box-Yellow Box-Blakely's Red Gum Grassy Woodland and Derived Native Grasslands Threatened Ecological Community’ occurs mainly in the eastern part of the subregion. ‘Weeping Myall Woodlands Threatened Ecological Community’ and ‘Coolibah - Black Box Woodlands of the Darling Riverine Plains and the Brigalow Belt South Bioregions Threatened Ecological Community’ are found more to the western part, and ‘Brigalow (Acacia harpophylla dominant and co-dominant) Threatened Ecological Community’ and associated ‘Semi-evergreen vine thickets of the Brigalow Belt (North and South) and Nandewar Bioregions Threatened Ecological Community’ grow throughout the central area of the subregion. The ‘Natural Grasslands On Basalt And Fine-Textured Alluvial Plains Of Northern New South Wales And Southern Queensland’ habitats cover most of area in the subregion (Figure 7).

Table 9 Water-dependent threatened ecological communities in the Gwydir subregion listed under the Commonwealth’s Environment Protection and Biodiversity Conservation Act 1999


Namea

Comment

Brigalow (Acacia harpophylla dominant and co-dominant) Threatened Ecological Community

Contains water-dependent assets, occurs over shallow groundwater or on floodplains

Coolibah - Black Box Woodlands of the Darling Riverine Plains and the Brigalow Belt South Bioregions Threatened Ecological Community

Likely to exhibit both surface water and groundwater dependence

Natural Grasslands On Basalt And Fine-Textured Alluvial Plains Of Northern New South Wales And Southern Queensland

On alluvial plains may exhibit surface water dependence

Semi-evergreen vine thickets of the Brigalow Belt (North and South) and Nandewar Bioregions Threatened Ecological Community

Contains water-dependent assets or may occur over areas of shallow groundwater

Weeping Myall Woodlands Threatened Ecological Community

Likely to be surface water dependent due floodplain habitat

White Box-Yellow Box-Blakely's Red Gum Grassy Woodland and Derived Native Grassland Threatened Ecological Community

Box woodlands may be groundwater dependent over areas of shallow groundwater

aPunctuation and typography appear as used in the asset list.

Data: Bioregional Assessment Programme (Dataset 1), Australian Government Department of the Environment (Dataset 17)

Figure 7

Figure 7 The six threatened ecological communities listed in the Commonwealth’s Environment and Biodiversity Conservation Act 1999 included in the water-dependent asset register

Names in the legend have been shortened. Full names can be found in Table 9.

Data: Bioregional Assessment Programme (Dataset 1), Australian Government Department of the Environment (Dataset 17)

Habitat of threatened ecological species

Thirty-four threatened species listed under the EPBC Act were identified in the Gwydir subregion (Bioregional Assessment Programme, Dataset 13). Of these, 15 were excluded from the water-dependent asset register because a demonstrated surface water or groundwater dependency of the habitat could not be established. The excluded assets include ten plant species, three bird species and two reptile species. Species included in the water-dependent asset register are listed in Table 10.

Table 10 Water-dependent threatened species in the Gwydir subregion listed under the Commonwealth’s Environment Protection and Biodiversity Conservation Act 1999

Although examples of individual species are listed, bioregional assessments consider the potential impacts to the habitat of the species not the individual species per se.


Functional group

Scientific namea

Common namea

Dependence on surface water

Dependence on groundwater

Comment

Plants

Homopholis belsonii

Belson’s Panic

Likely

Unlikely

May occur in areas with regular or intermittent flooding

Callistemon pungens

NA

Likely

Possible

Habitats range from riparian areas dominated by Casuarina cunninghamiana subsp. cunninghamiana to woodlands and rocky shrublands.

Cadellia pentastylis

Ooline

Likely

Possible

Ooline occurs in a range of vegetation types including semi-evergreen vine thickets, brigalow-belah, poplar box and bendee communities.

Swainsona murrayana

Slender Darling‑Pea

Likely

Possible

Associated with black box communities

Lepidium aschersonii

Spiny Pepper‑Cress

Likely

Possible

Occurs periodically in wet sites such as gilgai and margins of freshwater and saline marshes and lakes

Birds

Apus pacificus

Fork‑tailed Swift

Likely

Possible

Occurs over dry or open habitats, including riparian woodland and tea-tree swamps, low scrub, heathland or saltmarsh

Rostratula australis

Australian Painted Snipe

Likely

Possible

Inhabits shallow temporary and permanent wetlands

Monarcha melanopsis

Black‑Faced Monarch

Unlikely

Possible

Frequents moist forest, rainforests

Ardea ibis

Cattle Egret

Likely

Possible

Occurs in temperate grasslands, woodland and wetlands

Ardea alba

Great Egret

Likely

Possible

Prefers wide range of habitats-inland and coastal, freshwater and saline, permanent and ephemeral, open and vegetated, large and small, natural and artificial

Erythrotriorchis radiatus

Red Goshawk

Likely

Possible

Riverine forests are also used frequently.

Anthochaera Phrygia

Regent Honeyeater

Likely

Possible

Prefers fertile sites along creek flats, riparian vegetation

Myiagra cyanoleuca

Satin Flycatcher

Likely

Unlikely

Mainly inhabits eucalypt forests often near wetlands or watercourses

Geophaps scripta scripta

Squatter Pigeon (Southern)

Likely

Possible

Visits waterholes daily

Neochmia ruficauda ruficauda

Star Finch (Eastern)

Likely

Possible

Occurs mainly in grasslands and grassy woodlands that are located close to bodies of fresh water

Haliaeetus leucogaster

White‑Bellied Sea‑Eagle

Likely

Possible

Coastal habitats and terrestrial wetlands and riparian communities

Reptiles

Anomalopus mackayi

Five‑Clawed Worm‑Skink

Likely

Possible

Often associated with floodplain woodland communities

Mammals

Phascolarctos cinereus

Koala

Likely

Possible

Koalas are also found in vegetation communities dominated by Melaleuca or Casuarina species.

Dasyurus maculatus maculatus

Spot‑Tailed Quoll

Likely

Likely

Inland riparian and River Red Gum (Eucalyptus camaldulensis) forests

Data: Bioregional Assessment Programme (Dataset 1)

aPunctuation and typography appear as used in the asset list.

NA = not available

The asset list and other details are available from the water-dependent asset register and asset list (Bruce and O'Grady, 2016) and the asset database (Bioregional Assessment Programme, Dataset 1).

Last updated:
27 March 2017