The purpose of the landscape classification is to group landscape elements based on common characteristics with a focus on water and to facilitate a conceptual understanding of water dependency. The bioregional assessment (BA) landscape classification capitalises on existing classifications and regionalisation approaches that provide existing conceptual models. This facilitates a conceptual understanding of how hydrological regimes link to system level water requirements.
The classification for the PAE of the Namoi subregion uses broad-scale geomorphological, soil, hydrological and habitat information for a diverse range of landscape features to produce landscape classes that capture key distinctions using one or more of the following classifiers (Table 6):
- Broad habitat type (remnant/human-modified/aquatic)
- geomorphology (floodplain/non-floodplain)
- vegetation type (riparian/woodland floodplain/grassy woodland/rainforest)
- water regime (near-permanent/temporary)
- groundwater (groundwater dependent/non-groundwater dependent) or, in the case of springs, groundwater source (Great Artesian Basin (GAB)/non-GAB).
The classification broadly took a hierarchical approach in that certain types of landscape elements were given priority in developing a spatially complete landscape classification across the PAE. Prioritisation was assigned in order of highest to lowest as:
- aquatic ecosystems (e.g. wetlands, streams and lakes)
- remnant vegetation – areas of vegetation that contained relatively intact plant communities
- other landscape elements that are ‘non-remnant vegetation’ and are typically ‘human-modified’.
Landscape elements are classed as either ‘aquatic’, if mapped using wetlands, streams or springs datasets; ‘remnant’, if they are mapped in the NSW regional native vegetation mapping (NSW OEH, Dataset 3) and do not include ‘non-native’ or ‘candidate native grasses’ within the ‘Keith Form’ classification (Keith, 2004); and ‘human-modified’ for all remaining landscapes not covered by the aquatic and remnant areas (see Table 6). This classifier delineates between ‘human-modified’ landscapes and those that are relatively intact. This distinction has important consequences for defining where important habitats and biota may occur when considering assets and their likely distribution.
Vegetation communities are broadly classified based primarily on existing classification within the NSW regional native vegetation mapping (NSW OEH, Dataset 3 and Table 6) (Keith, 2004). Riparian and floodplain woodland vegetation are defined as separate classes based on their importance in riverine and floodplain environments. Rainforest remnants are also defined separately given their high ecological value within the landscape. Riparian remnants on non-floodplain or upland areas are distinguished from other non-floodplain vegetation communities. The remaining non-floodplain woodland, shrubland and grassland communities were aggregated into a ‘grassy woodlands’ classification.
The aquatic features (wetlands) and remnant vegetation are classified based on whether they occur on floodplain or non-floodplain areas (Table 6). The spatial distribution of wetland elements were derived from the existing Australian National Aquatic Ecosystem (ANAE) classification framework for wetlands (excluding riverine habitats) (SEWPaC, Dataset 4) and the NSW regional native vegetation mapping (NSW OEH, Dataset 3). This distinction was made using the maximum flooding extent using the Namoi Valley floodplain atlas (NSW OEH, Dataset 5). This helps to broadly characterise which landscape features, such as wetlands, might be influenced by flooding regimes that are more likely to support water-dependent vegetation and habitats.
Riverine or instream landscape elements were classified according to topography using upland versus lowland distinctions and the water regime (temporary or permanent). The distribution and persistence of riverine ecosystems is influenced largely by water regime and is a key attribute for differentiating and characterising habitats and ecosystems. In this case the existing ANAE classification framework of streams (SEWPaC, Dataset 4) was aggregated to produce four separate riverine categories that were subsequently classified according to association with GDEs (Table 6). The association of riverine landscape features with GDEs was assessed using the National atlas of groundwater dependent ecosystems (GDE Atlas; Bureau of Meteorology, 2012; Bioregional Assessment Programme, Dataset 7). This dataset was used because the NSW GDE mapping and classification does not cover streams and riverine habitat. The spatial overlap between stream segments and those GDE elements that were defined as ecosystems dependent on the surface expression of groundwater in the GDE Atlas was used to classify the riverine ecosystems (Table 6). The potential for different wetland or vegetation elements to access or interact with groundwater is based on their spatial overlap with those areas identified as high potential GDEs in the NSW GDE mapping and classification (NSW Office of Water, Dataset 6). This dataset was used over the GDE Atlas because it has been mapped at a finer spatial resolution and uses the NSW native vegetation mapping as a basis for the delineation of landscape elements (NSW OEH, Dataset 3). The NSW Department of Primary Industries Water methodology (Kuginis et al., 2016) defines GDEs as ecosystems ‘which have their species composition and natural ecological processes wholly or partially determined by groundwater’. Dependence on groundwater can range from obligate to partial or infrequent (Zencich et al., 2002) but excludes species that rely exclusively on soil water in the vadose zone. The classification of mapped GDEs is based on Keith’s (2004) classification of vegetation communities. The landscape classification approach uses Keith’s (2004) classification of ‘formations’ and ‘classes’ to vegetation types associated with these GDEs. Data on the distribution of GDEs within the PAE of the Namoi subregion were based on multiple lines of evidence that included remote sensing of vegetation condition, watertable data, vegetation community and landscape information (Kuginis et al., 2016).
Land use mapping data (ABARES, Dataset 2) were used to classify all landscape elements identified as ‘non-remnant’ into six land use types (Table 6) that comprise the human-modified group of landscape classes:
- conservation and natural environments
- intensive uses
- modified water bodies
- production from dryland agriculture and plantations
- production from irrigated agriculture and plantations
- production from relatively natural environments.
The logic of the landscape classification rule sets used in the landscape classification for the Namoi subregion is shown in Figure 19.
GAB = Great Artesian Basin, GDE = groundwater-dependent ecosystem
Table 6 Relevant datasets and key rule sets used for the landscape elements
Relevant datasets |
Broad habitat type |
Geomorphology |
Vegetation type |
Water regime |
Groundwater |
---|---|---|---|---|---|
Water-dependent asset register and asset list for the Namoi subregion (Bioregional Assessment Programme, Dataset 8) |
Springs (points): spatial intersect with [asset name] contains ‘Spring GDE’ (Bioregional Assessment Programme, Dataset 8) |
na |
na |
na |
GAB: [GMA_DS] = ‘Great Artesian Basin’ (Bioregional Assessment Programme, Dataset 8) |
na |
na |
na |
Non-GAB: Not [GMA_DS] = ‘Great Artesian Basin’ (Bioregional Assessment Programme, Dataset 8) |
||
ANAE streams (SEWPaC, Dataset 4); GDE Atlas – GDE surface layer (Bioregional Assessment Programme, Dataset 7) |
Streams (lines and polygons): spatial intersect with ‘ANAE streams’ (SEWPaC, Dataset 4) |
Upland: If [ANAEstT] contains ‘upland’ OR ‘transitional’ (SEWPaC, Dataset 4) |
na |
Permanent: If [ANAEstT] contains ‘permanent’ (SEWPaC, Dataset 4) |
GDE: Spatial intersect with ‘GDE_sur’ (Bioregional Assessment Programme, Dataset 7) |
Lowland: If [ANAEstT] contains ‘lowland’ (SEWPaC, Dataset 4) |
na |
Temporary: If [ANAEstT] contains ‘temporary’ (SEWPaC, Dataset 4) |
Non-GDE: No spatial intersect with ‘GDE_sur’ data layer (Bioregional Assessment Programme, Dataset 7) |
||
ANAE wetlands (SEWPaC, Dataset 4); Namoi Valley floodplain atlas 1979 (NSW OEH, Dataset 5), NSW groundwater-dependent ecosystem mapping (NSW Office of Water, Dataset 6); NSW regional vegetation (NSW OEH, Dataset 3) |
Wetlands (polygons): spatial intersect with ‘ANAE wetlands’ (SEWPaC, Dataset 4) OR ‘NSW regional vegetation’[Keith_form] = ‘freshwater wetlands’ (NSW OEH, Dataset 3) |
Floodplain: Spatial intersect with ‘floodplain atlas’ layer (NSW OEH, Dataset 5) |
na |
na |
GDE: Spatial intersect with ‘NSW_GDE’ data layer (NSW Office of Water, Dataset 6) |
Non-floodplain: No spatial intersect with ‘floodplain atlas’ layer (NSW OEH, Dataset 5) |
na |
na |
Non-GDE: No spatial intersect with ‘NSW_GDE’ data layer (NSW Office of Water, Dataset 6) |
||
NSW regional vegetation (NSW OEH, Dataset 3); NSW groundwater-dependent ecosystem mapping (NSW Office of Water, Dataset 6) |
Remnant vegetation (polygons): spatial intersect with ‘NSW regional vegetation’; excluding [Keith_form] = ‘non-native’ OR ‘candidate native grasses’ OR ‘freshwater wetlands’ AND ‘ANAE wetlands’ layer (NSW OEH, Dataset 3; SEWPaC, Dataset 4) |
Floodplain: If [Keith_class] contains ‘floodplain’ OR ‘inland riverine forests’ (NSW OEH, Dataset 3) |
Floodplain riparian forest: If [Keith_class] = ‘inland riverine forests’ (NSW OEH, Dataset 3) |
na |
GDE: spatial intersect with ‘NSW_GDE’ data layer ( NSW Office of Water, Dataset 6) |
Floodplain grassy woodland: [Keith_class] = ‘floodplain’ OR ‘riverine’ AND NOT [Keith_form] = ‘forested wetlands (NSW OEH, Dataset 3) |
Na |
Non-GDE: no spatial intersect with ‘NSW_GDE’ data layer (NSW Office of Water, Dataset 6) |
|||
Non-floodplain: NOT [Keith_class] contains ‘floodplain’ OR ‘inland riverine forests’ (NSW OEH, Dataset 3) |
Rainforest: [Keith_form] = ‘rainforests’ OR ‘wet sclerophyll forests’ (NSW OEH, Dataset 3) |
na |
GDE: spatial intersect with ‘NSW_GDE’ data layer (NSW Office of Water, Dataset 6) |
||
Non-GDE: no spatial intersect with ‘NSW_GDE’ data layer (NSW Office of Water, Dataset 6) |
|||||
Grassy woodland: NOT [Keith_form] = ‘rainforests’ OR ‘wet sclerophyll forests’ (NSW OEH, Dataset 3) |
na |
GDE: spatial intersect with ‘NSW_GDE’ data layer (NSW Office of Water, Dataset 6) |
|||
Non-GDE: no spatial intersect with ‘NSW_GDE’ data layer (NSW Office of Water, Dataset 6) |
|||||
Riparian forest: [Keith_class] = ‘eastern riverine forests’ (NSW OEH, Dataset 3) |
na |
na |
|||
Australian land use mapping (ABARES, Dataset 2); NSW regional vegetation (NSW OEH, Dataset 3) |
Human-modified landscapes (polygons): spatial intersect with [Keith_form] = ‘non-native’ OR ‘candidate native grasses’ (NSW OEH, Dataset 3) |
‘Human-modified’ landscape class: [Primary_v7](ABARES, Dataset 2) |
|
|
|
ANAE = Australian National Aquatic Ecosystems, GAB = Great Artesian Basin, GDE = groundwater-dependent ecosystem, na = not applicable
Product Finalisation date
- 2.3.1 Methods
- 2.3.2 Summary of key system components, processes and interactions
- 2.3.3 Ecosystems
- 2.3.4 Coal resource development pathway
- 2.3.5 Conceptual modelling of causal pathways
- Citation
- Acknowledgements
- Currency of scientific results
- Contributors to the Technical Programme
- About this technical product