Native vegetation

Native vegetation comprises plants that are indigenous to Australia, including trees, shrubs, sedges, herbs and grasses, and incorporates lower lifeforms such as mosses, lichens and fungi. Many of our diverse types of native vegetation have adapted to cope with Australia’s highly variable climate, ancient nutrient-depleted soils and ubiquitous fire regimes (Keith 2017). The unique character of our vegetation is embedded within Australia’s cultural identity. Indeed, from Indigenous peoples’ perspective, a sense of place and belonging can be defined by Country. For instance, people of the wet tropics of northern Queensland identify as Rainforest People.

Native vegetation is crucial for the health of Australia’s environment – it stabilises soil, supports pollinators and other animals, purifies water, stores carbon, and provides food and habitat for biodiversity. Many of Australia’s tree species depend on soil microbes for their survival – for example, through close associations with specialised fungi known as mycorrhizae (see Soil). Vegetation and fungi together provide a foundation of the food chain for land-based ecosystems and biodiversity. All these services also support our economy.

The economic value of native vegetation is immense, but not yet fully quantified in Australia. In many parts of Australia, native vegetation has been cleared or degraded and fragmented by human activity to enable other uses of the land (see Pressures). As a result, many of Australia’s unique plants and animals have become endangered (see the Biodiversity chapter). However, in recent years, Australia has invested significantly in the sustainable use and conservation of native vegetation, including efforts to manage and protect natural areas (see Protected areas), and begin to restore degraded landscapes to functioning systems (see Retaining and restoring natural capital assets). Despite these policy responses, Australia’s native vegetation continues to decline in extent and condition, suggesting the investment may not always be directed to the areas that need it most (Evans 2016, Reside et al. 2017, Ward et al. 2019).

Vegetation extent

Overall, 13.2% of Australia’s native vegetation, as mapped by state and territory agencies across Australia, has been replaced by urban, production and extractive uses of the land (Figure 2) (DAWE 2020g) (see Land use). Regrowth and other modified native vegetation make up a further 0.3% of the land area. The native vegetation that remains makes up 86.5% of the continental land area. Hummock Grasslands, Acacia Shrublands and Eucalyptus Woodlands together make up 47% of the current extent of native vegetation across Australia. Vegetation groups vary in the diversity of native species they support (see the Biodiversity chapter).

Eleven major vegetation groups have lost at least 20% of their original extent (Figure 3). Eucalypt Woodlands have been extensively cleared, with 67% of the pre-1750 extent remaining (see Land clearing). Other major vegetation groups have even less of their original extent remaining. For example, Casuarina Forests and Woodlands, which make up 0.4% of all native vegetation that remains (Figure 2), have only around half of their original extent (53%) remaining (Figure 3).

Figure 2 Distribution and extent of MVGs mapped in the National Vegetation Information System version 6.0

MVG = major vegetation group

Notes:

  1. Each state and territory undertakes field ecological surveys and variously integrates with data from aerial photography and satellite remote sensing to interpret and map the extent of their native vegetation. Those data are aggregated at the national level using data standards developed under the National Vegetation Information System (NVIS Technical Working Group 2017). Each jurisdiction’s definition of native vegetation is different, resulting in differences in the mapped interpretation of remnant vegetation.
  2. Total area of remaining native vegetation: 664 million hectares (86.5% of the Australian continent).
  3. Numbers against native MVGs in the legend are the extent of that MVG as a percentage of the total remaining native vegetation.
  4. Area of Cleared, non-native vegetation, buildings: 102 million hectares (13.2% of the Australian continent).
  5. Area of Regrowth, modified native vegetation: 2 million hectares (0.3% of the Australian continent).

Sources: DAWE (2020g), using highly variable dates for source datasets from different states; map projection: Australian Albers GDA94 (ICSM n.d.)

Figure 3 Extent of remnant, regrowth/modified and removed native vegetation for each MVG, labelled with the extent of remnant native vegetation in that group as a percentage of its pre-1750 extent

MVG = major vegetation group

Notes:

  1. The classification and extent of native MVGs derive from pre-1750 mapping (DAWE 2020h). The current status of each pre-1750 MVG is assessed by comparing with the extant MVG mapping (DAWE 2020g) using the following categories:
  2. ‘Remnant’ is the area within the extent of each pre-1750 MVG (DAWE 2020i) that remains extant native vegetation (i.e. any one of the MVGs listed as ‘remnant native vegetation’ in Figure 2).
  3. ‘Removed’ is the area within the extent of each pre-1750 MVG (DAWE 2020i) that is now in the following extant MVG (DAWE 2020j): Cleared, non-native vegetation, buildings.
  4. ‘Regrowth/modified’ is the area within the extent of each pre-1750 MVG (DAWE 2020i) that is now in the following extant MVG (DAWE 2020j): Regrowth, modified native vegetation.
  5. MVGs not shown: Unclassified forest, Unclassified native vegetation, Sea and estuaries, and Unknown/no data.

Sources: Based on DAWE (2020g), DAWE (2020h)

Overall, the amount of ‘remnant’ native vegetation mapped in datasets published in 2020 has reduced by around 1.36 million hectares (ha) compared with the 2012 dataset (Table 1). This is largely a net result of an additional 1.26 million ha mapped as ‘removed’ and 0.24 million ha mapped as ‘regrowth/modified’ in areas previously identified as ‘remnant’ native vegetation. There is an additional 0.99 million ha of ‘removed’ native vegetation and 1.15 million ha of ‘regrowth/modified’ vegetation compared with datasets published in 2012; 0.30 million ha previously classed as ‘removed’ is now classed as ‘regrowth/modified’.

National Greenhouse Accounts data roughly accord with the story of clearing and regrowth seen in the national vegetation data: overall across Australia and over time, primary vegetation is cleared, some regrows and some regrowth is recleared, but generally and cumulatively the extent of removed native vegetation increases (see Land clearing).

Native vegetation that has been removed or partially regrown has reduced ecological integrity. However, the extent of ‘remnant’ and ‘regrowth/modified’ native vegetation (Figure 2; Table 1) is not assessed based on its condition. Additional information is needed to assess the growth stage and ecological integrity of ‘remnant’ and ‘regrowth/modified’ vegetation for a more comprehensive understanding of the implications for biodiversity and land condition (see Vegetation condition).

Table 1 Native vegetation change matrix comparing extant NVIS datasets published in 2012 (version 4.1) and 2020 (version 6.0)

Stock

Removed (ha)

Remnant (ha)

Regrowth/modified (ha)

Not applicable (ha)

Opening stock

(NVIS 4.1 published in 2012)

100,480,723

665,380,436

1,047,420

2,491,405

Removed

0

−1,262,780

301,626

−32,091

Remnant

1,262,780

0

241,793

−141,480

Regrowth/modified

−301,626

−241,793

0

−611,356

Not applicable

32,091

141,480

611,356

0

Closing stock

(NVIS 6.0 published in 2020)

101,473,968

664,017,343

2,202,195

1,706,478

ha = hectare; MVG = major vegetation group; MVS = major vegetation subgroup; NVIS = National Vegetation Information System

Notes:

  1. Areas are based on NVIS extant (‘present’) vegetation mapping. Specifically, NVIS v4.1 MVS (DSEWPaC 2012) and NVIS v6.0 MVG (DAWE 2020g), using the following categories:
    ‘Remnant’ is the area within the ‘present’ extent of MVSs in NVIS v4.1 (DSEWPaC 2012) or the MVGs in NVIS v6.0 (DAWE 2020g). In the case of NVIS v6.0, any one of the MVGs listed as ‘remnant native vegetation’ in Figure 2.
    ‘Removed’ is the area within the ‘present’ extent of MVSs in NVIS v4.1 (DSEWPaC 2012) or the MVG in NVIS v6.0 (DAWE 2020j): Cleared, non-native vegetation, buildings.
    ‘Regrowth/modified’ is the area within the ‘present’ extent of MVSs in NVIS v4.1 (DSEWPaC 2012) or MVG in NVIS v6.0  (DAWE 2020j): Regrowth, modified native vegetation.
    ‘Not applicable’ comprises Sea and estuaries, and Unknown/no data.

2. NVIS is an aggregation of each jurisdiction’s mapping of native vegetation extent, and the timestamps of these source datasets are highly variable.

In 2016, Australia had 134 million ha of forest covering 17% of the total land area, including nearly 2 million ha of plantation and other non-native forest types, making up 3% of the world’s forests (Table 1.2 in MPIGA & NFISC 2018). Most forests occur along the northern, eastern, south-eastern and south-western coasts of Australia, generally where average rainfall exceeds 500 millimetres per year; however, they can also be found in drier parts of the country. The National Greenhouse Accounts additionally identify 65 million ha of sparse woody vegetation that does not meet the strict definition of a forest used for international reporting (DISER 2021d) (see Carbon).

A comprehensive third edition of the source book on Australia’s native vegetation was published in 2017 (Keith 2017). This fully updated edition presents the latest insights on the patterns and processes that shaped the vegetation of Australia, and provides detailed ecological portraits for each major vegetation type.

Vegetation condition

The condition of native vegetation is assessed in terms of its integrity or capacity to continue providing habitat to support Australia’s unique biodiversity. This is consistent with Australia’s former Native Vegetation Framework (COAG Standing Council on Environment and Water 2012), in which condition is defined as ‘the capacity of a native vegetation community to support the full range of native species that might be expected to use a stand of vegetation of a particular type under natural circumstances’. Areas of high ecological integrity are also well placed to provide valuable ecosystem services such as pollination, water purification and nutrient cycling.

Removed or degraded habitats directly and indirectly cause long-term and cumulative declines in local and regional biodiversity due to, for example, fragmentation, edge effects and invasion by non-native species (Haddad et al. 2015, Neldner 2018, Sonter et al. 2018, Kearney et al. 2019) (see Introduced and invasive species) (see the Biodiversity chapter).

Native vegetation supports a wide range of land uses, such as grazing, honey production, wood product extraction, infrastructure networks and a wide range of recreational opportunities (see Land use). These land uses, while providing social and economic benefits, result in reduced capacity of habitats to support the biodiversity originally found there.

The cumulative impact of multiple pressures over many decades across regions and landscapes, and especially in intensive land-use zones, exacerbates fragmentation and further contributes to reductions in the quality of remnant native vegetation as habitat for Australia’s unique flora and fauna (see the Biodiversity chapter). Of the 18 ecosystems identified by Bergstrom et al. (2021) to be at risk of collapse – potentially irreversible change to ecosystem structure, function and composition – 10 are terrestrial (see the Biodiversity chapter). An understanding of the drivers and pressures associated with ecosystem collapse is needed to determine threat status using the International Union for Conservation of Nature (IUCN) Red List of Ecosystems (Keith et al. 2013, Bland et al. 2017, Bland et al. 2018). The IUCN aims to use this framework to assess the risk of collapse for all the world’s ecosystems by 2025 (Sato & Lindenmayer 2018).

As we enter a period of unprecedented environmental change, we can expect many ecosystems to undergo sudden, unpredictable and often irreversible transitions to new states, despite how well adapted the Australian biota is to climate variability (Harris et al. 2018) (see Climate change). Already, in one unprecedented event in the summer of 2019–20, bushfires burned more than 8 million hectares of native vegetation across 11 bioregions, and 17 major vegetation types were severely burned (Godfree et al. 2021). The massive scale of the impacts in general, and particularly on fire-sensitive ecosystems such as the Gondwana rainforests, may leave some ecosystems susceptible to collapse and exacerbate biodiversity decline (Ward et al. 2020, Godfree et al. 2021). To monitor and track outcomes, multiple indicators will be needed to capture the different dimensions of ecosystem type, extent, condition and risk of collapse (Nicholson et al. 2021). Approaches that integrate observations with models and future scenarios will be fundamental to ensuring those indicators are well founded (Nicholson et al. 2019) and support the broader community in planning their future (Pereira et al. 2020).

Habitat modification

Condition is quantified by measuring the similarity of a current ecosystem to a historical reference state with high ecological integrity or one that is minimally impacted by people (UNCEEA 2021). The condition of habitat for biodiversity is generally inversely related to the degree to which the land has been modified for agricultural production, resource extraction, urbanisation and related uses (see Land use). Habitats can also be degraded by altered disturbance regimes such as fires outside the normal range of intensity and fire return intervals (Gosper et al. 2019, Tran et al. 2020, Gallagher et al. 2021).

The intensity of land use by people has been used as a proxy for levels of habitat modification and thereby related to ecosystem intactness or integrity (Watson & Venter 2019). For example, the human footprint (a quantitative analysis of human influence; Scott 2020), which uses mapped information such as the built environment, population density, land use and infrastructure networks, showed that by 2009, 75% of the globe was experiencing measurable human pressures (Venter et al. 2016a, Venter et al. 2016b). Beyer et al. (2020) used the human footprint data to assess ecoregion intactness as a measure of habitat quality for biodiversity. They found that most ecoregions in eastern Australia appear to be transitioning to highly degraded states. Williams et al. (2020b) and Williams et al. (2020a) updated the map of the human footprint and reported that by 2013 58.4% of Earth’s surface was highly modified, although Australia was one of the few regions they considered relatively intact (Figure 4). In a related global analysis incorporating landscape connectivity, Grantham et al. (2020) reported that only 40% of the world’s forests remained intact. On a scale of 1 to 10 (lowest to highest integrity), Australia’s remaining native forests scored 7.22 for landscape integrity in 2019 (Grantham et al. 2020). This analysis did not account for the original extent of native forests in Australia, which would have reduced the score.

Figure 4 Human footprint map for Australia, 2013

Within Australia, most states and territories have developed field protocols for benchmarking and measuring habitat condition to support regulation of native vegetation clearing and management (e.g. Parkes et al. 2003, Michaels 2006, Eyre et al. 2015). Those field protocols typically comprise 2 components of condition: a local site-level score and a landscape-level score to account for the effects of fragmentation on the site. New South Wales and Victoria have separately developed methods to map condition spatially, incorporating both local and landscape contexts (Newell et al. 2006, DSE 2007, Love et al. 2020). Queensland is also developing a mapping methodology to accompany their BioCondition field protocol (Eyre et al. 2018).

In New South Wales in 2013, only 33% of the original habitat effectiveness (based on an analysis of ecological carrying capacity) remained to support native species (DPIE 2020d) (Figure 5). Fragmentation had reduced the site-level score of habitat effectiveness by 25% (Love et al. 2020). In 2018, the New South Wales Government reported that only 15% of remnant native vegetation was in close-to-natural (i.e. benchmark) condition (NSW EPA 2019). Following the extensive bushfires of 2019–20, the New South Wales Department of Planning, Industry and Environment (DPIE 2020b) reported ecological carrying capacity in the fireground was reduced by 39% compared with 2013. That assessment reflected the immediate post-fire effects, with expected improvements in future assessments where there is regeneration and regrowth (DPIE 2020b).

Figure 5 Ecological carrying capacity of terrestrial habitat in (a) New South Wales in 2013, and (b) for part of the Brigalow Belt South (BBS) bioregion, adjacent to the Sydney Basin (SYB) bioregion

Notes:

  1. Bioregion codes are defined in Thackway & Cresswell (1995) and DoE (2016).
  2. This indicator of ecological carrying capacity uses connectivity to account for fragmentation.

Sources: Adapted from DPIE (2020d), based on data from Love et al. (2020); map projection: Geographic GDA94 (ICSM n.d.)


National monitoring

The development of a national monitoring system to measure changes in the condition of representative native vegetation communities across Australia by 2016 was a target under Australia’s former national Native Vegetation Framework (COAG Standing Council on Environment and Water 2012:46). In the Land chapter of the 2016 state of the environment (SoE) report, Metcalfe & Bui (2017:111) reported the steps being taken by the CSIRO (Harwood et al. 2016) in developing a remote-sensing approach to consistently monitor habitat condition nationally. The Habitat Condition Assessment System (HCAS) has since evolved (Williams et al. 2020c, Williams et al. 2021b) and provides, for the first time, an independent basis for national reporting on site-level habitat condition that is not closely coupled to land-use mapping (see case study: Assessing condition of habitat consistently and nationally).

This national analysis of site-level habitat condition identifies the most intensively used regions – those associated with the major agricultural areas – for example, the ‘southern volcanic plain’ and ‘south-eastern coastal plain’ bioregions adjacent to Melbourne, the southern and agricultural parts of South Australia, and the Avon Wheatbelt in Western Australia (Figure 6) (see Agriculture).

Figure 6 Bioregional patterns of mean native vegetation condition used to define 3 land-use intensity zones, 2001–18

ELZ = extensive land-use zone; HCAS = Habitat Condition Assessment System; IBRA = Interim Biogeographic Regionalisation for Australia; ILZ = intensive land-use zone; RNZ = relatively natural zone

Notes:

  1. Derived from HCAS v2.1 (see case study: Assessing condition of habitat consistently and nationally). The inset map shows 3 land-use intensity zones delineated by the thick black boundaries on the main map. The ILZ is where the mean HCAS scores are ≤0.7. The ELZ is where the mean HCAS scores are >0.7 and ≤0.8. The RNZ is where the mean HCAS scores are >0.8.
  2. The legend shows the continuous HCAS v2.1 score grouped into 0.1 classes and relates these to the Vegetation Assets, States and Transitions (VAST) framework narrative (Thackway & Lesslie 2006) to guide interpretation, labelled as ‘residual’, ‘modified’, ‘transformed’, ‘replaced’ or ‘removed’.

Sources: HCAS v2.1 (2001–18) from Williams et al. (2021b); VAST framework from Thackway & Cresswell (1995); IBRA 7 bioregions from DoE (2016); map projection: Australian Albers GDA94 (ICSM n.d.)

All remaining native vegetation (Figure 2) has been ‘modified’ to some extent across its range (represented by HCAS scores below 0.8) and some to a very high degree (HCAS scores below 0.6) as of 2018 (Figure 7). In cleared areas, native vegetation has been substantially ‘replaced’ or ‘removed’ (lowest mean HCAS score of 0.2; Figure 7). The most intact vegetation groups (highest mean HCAS scores approaching 0.9; Figure 7) are those that dominate Australia’s remote arid interior, including Acacia Open Woodlands, Acacia Shrublands and Hummock Grasslands. However, even these systems are vulnerable to collapse due to invasion by transformer weeds such as buffel grass, which is altering fire regimes, compounded by heatwaves (Bergstrom et al. 2021) (see Introduced and invasive species). This assessment uses HCAS as of 2018 (Williams et al. 2021b), before landscape-level impacts of catastrophic fires in the summer of 2019–20 (Godfree et al. 2021). In future analyses, the additional effects of fragmentation will also be incorporated (see case study: Assessing condition of habitat consistently and nationally).

Figure 7 Variability in terrestrial habitat condition in Australia’s MVGs

HCAS = Habitat Condition Assessment System; MVG = major vegetation group; NVIS = National Vegetation Information System; VAST = Vegetation Assets, States and Transitions

Notes:

  1. The box and whisker plots show the distribution of habitat condition scores between 0.0 and 1.0 for 5 summary statistics: minimum to first quartile (left whisker), first quartile to third quartile (box), median (line inside the box), and third quartile to maximum (right whisker). All MVGs have at least one 250-metre pixel with a minimum value of 0.0 and at least one other with a maximum value of 1.0, so whiskers cover the full range.
  2. Interpretation of scores follows the VAST framework narrative (Thackway & Lesslie 2006) shown in Figure 6 (residual, modified, transformed, replaced, removed).
  3. NVIS v6.0 pre-1750 MVGs not shown: Mangroves; Inland Aquatic – freshwater, salt lakes, lagoons, Unclassified native vegetation; Unclassified forest; Unknown/no data. HCAS v2.1 condition scores do not apply to these MVGs.
  4. Excluded from analysis: commercial plantation forestry – defined by MPIGA & NFISC (2018); inland water bodies and salt lakes – defined by ‘AHGFWaterbodyLargest’ polygon in BOM (2012); and the Water Observations from Space dataset over the period 2001–14 indicating >80 water presence (GA 2015). These areas did not contribute to the HCAS v2.1 summary statistics for each MVG.
  5. The following MVGs are not native vegetation: Regrowth, modified native vegetation; Cleared, non-native vegetation, buildings.

Sources: HCAS v2.1 (2001–18), described in Williams et al. (2021b); NVIS v6.0 pre-1750 MVGs from DAWE (2020g)

Figure 8 illustrates the relative degree of modification of Australia’s pre-1750 native vegetation across the continent as assessed by HCAS and equated with the Vegetation Assets, States and Transitions (VAST) narrative framework (see Figure 3 for extent). Only around 40% of the formerly extensive Eucalypt Woodlands appear relatively intact at the site level (VAST ‘residual’ class, HCAS (Metcalfe & Bui 2017), there are significant departures (e.g. lower than expected modification of Callitris Forests and Woodlands, Acacia Forests and Woodlands, Tussock Grasslands, and Acacia Open Woodlands). These departures are in part due to data currency and to a reliance of the VAST framework implementation (Lesslie et al. 2010) on pressures projected from land-use mapping that may not yet be fully realised. The differences may also be due to how the VAST framework is quantitively related to the HCAS scores. More work needs to be done to comprehensively assess and map the extent and condition of Australia’s native vegetation, its states and transitions, and potential for recovery. The framework developed by Richards et al. (2020) provides a starting point for organising data and expert knowledge for this effort.

Figure 8 Extent of modification of MVGs

HCAS = Habitat Condition Assessment System; MVG = major vegetation group; NVIS = National Vegetation Information System

Notes:

  1. Assessed using HCAS v2.1 (see case study: Assessing condition of habitat consistently and nationally). Condition scores are aggregated in 5 classes of 0.2 increments for comparison with Figure LAN30 in the 2016 state of the environment report (Metcalfe & Bui 2017), and related to the Vegetation Assets, States and Transitions (VAST) framework narrative (Thackway & Lesslie 2006) to guide interpretation: residual, modified, transformed, replaced, removed.
  2. NVIS v6.0 pre-1750 MVGs not shown: Mangroves; Inland Aquatic – freshwater, salt lakes, lagoons; Unclassified native vegetation; Unclassified forest; Unknown/no data. HCAS v2.1 condition scores do not apply to these MVGs.
  3. Excluded from analysis: commercial plantation forestry – defined by MPIGA & NFISC (2018); inland water bodies and salt lakes – defined by ‘AHGFWaterbodyLargest’ polygon in BOM (2012); and the Water Observations from Space dataset over the period 2001–14 indicating >80 water presence (GA 2015). These areas did not contribute to the HCAS v2.1 summary statistics for each MVG.

Sources: HCAS v2.1 (2001–18) described in Williams et al. (2021b); NVIS v6.0 pre-1750 MVGs from DAWE (2020h)

Case Study Assessing condition of habitat consistently and nationally

The CSIRO and the Australian Government Department of Agriculture, Water and the Environment (DAWE) have been collaborating on the development of the national Habitat Condition Assessment System (HCAS) since 2015. HCAS was developed to address the need for nationally consistent, landscape-wide, site-level estimates of habitat condition to inform the conservation of Australia’s wildlife and natural heritage (DAWE 2020b, DAWE 2021d, DAWE 2021b). The remote-sensing approach developed by CSIRO aims to predict the quality of (mainly terrestrial) habitats in terms of the ‘capacity of a location to provide the structures and functions necessary for the persistence of all species naturally expected to occur there, as if it were in an intact reference state’. The purpose of HCAS is to distinguish natural variations in ecosystem responses to periodic disturbance from those attributed to land-use and management practices. Therefore, several years may be needed to confirm whether the trend after a disturbance is declining, steady or improving.

The resulting HCAS dataset predicts site-level habitat condition for terrestrial biodiversity, with scores ranging from 0.0 (habitat completely removed) to 1.0 (habitat in reference condition). HCAS version 2.1 is a cumulative assessment of site-level habitat condition over 18 years to 2018, as depicted by the MODIS (Moderate Resolution Imaging Spectroradiometer) satellite’s optical sensor (Harwood et al. 2021b, Williams et al. 2021b) (Figure 9). HCAS on its own does not directly consider fragmentation (although such information can be derived from HCAS) and therefore potentially underestimates the loss of regional ecological integrity, especially in the intensive land-use zone.

As a site-level estimate of condition, HCAS is intended as an input to other analyses, such as connectivity, to also account for the landscape consequences of fragmentation on ecosystem integrity. When these 2 dimensions of habitat condition are combined, they provide a means to consistently assess the quality of habitat, in terms of its capacity to retain biodiversity (Ferrier & Drielsma 2010). The integrated result can be used to support strategic prioritisation for natural resource management and, with repeated assessments over time, provide trends and trajectories of change.

Comparisons with state agency mapping for Victoria (Newell et al. 2006, DSE 2007) and New South Wales (Love et al. 2020) indicate that, while trends are similar, HCAS version 2.1 presents a more optimistic view of habitat condition in the more intensively used regions. For example, the HCAS version 2.1 mean value for New South Wales is 0.63 (Williams et al. 2021b) compared with 0.44 estimated by Love et al. (2020), who used Landsat data and estimated the likely effects of land use on understorey and groundcover intactness. In part, this difference may relate to the limited ability of satellites to comprehensively observe the structure, function and compositional characteristics of Australia’s ecosystems, and especially of the understorey. However, satellite monitoring is expected to rapidly accelerate over the next few years with the introduction of new sensor systems, enabling more comprehensive assessment of changes in ecosystem condition (see case study: Digital Earth Australia: new technologies and partnerships to map Australia’s land).

Figure 9 A national perspective on habitat condition for terrestrial biodiversity, showing the continuous site-level score in 5 classes that approximate the VAST narrative framework

HCAS = Habitat Condition Assessment System; VAST = Vegetation Assets, States and Transitions

Notes:

  1. HCAS estimates departure from reference (intact ecosystems) as depicted by the MODIS (Moderate Resolution Imaging Spectroradiometer) satellite remote sensing of vegetation cover for 250 × 250-metre pixels. HCAS scores less than 0.4 potentially represent places where some dominant structuring plant species indigenous to the locality may still be present but the land is largely under some form of cultivation. At lower scores (<0.2) the indigenous species have most likely been replaced by some form of intensive land use.
  2. Excluded: water bodies, salt lakes.

Sources: Williams et al. (2021b), Harwood et al. (2021b); map projection: Australian Albers GDA94 (ICSM n.d.)

Assessment Native vegetation extent and condition
2021
2021 Assessment graphic showing the environment is in poor condition, resulting in diminished environmental values, and the situation is deteriorating.
Adequate confidence

Ongoing clearing of native vegetation and intensification of land use in remnant areas continue to degrade environmental values.
Related to United Nations Sustainable Development Goal targets 15.1, 15.2, 15.4

Assessment Native vegetation extent and condition in intensive land-use zone
2021
2021 Assessment graphic showing the environment is in very poor condition, resulting in heavily degraded environmental values, and the situation is deteriorating.
Adequate confidence
2016
Assessment graphic from 2011 or 2016 showing the environment was in very poor condition, resulting in heavily degraded environmental values, and the situation was deteriorating.
2011
Assessment graphic from 2011 or 2016 showing the environment was in poor condition, resulting in diminished environmental values, and the situation was deteriorating.

Many native ecosystems have been extensively cleared and at least 50% of remaining habitats are highly degraded. There are local areas of restoration and regrowth.

Assessment Native vegetation extent and condition in extensive land-use zone
2021
2021 Assessment graphic showing the environment is in poor condition, resulting in diminished environmental values, and the situation is deteriorating.
Adequate confidence

Some clearing of native ecosystems and more extensive grazing pressures have reduced the overall quality. Land-use intensification and conversion, as well as increasingly frequent and intense fires, contribute to degradation.

Assessment Native vegetation extent and condition in relatively natural zone
2021
2021 Assessment graphic showing the environment is in good condition, resulting in stable environmental values, but the situation is deteriorating.
Adequate confidence
2016
Assessment graphic from 2011 or 2016 showing the environment was in good condition, resulting in stable environmental values, but the situation was deteriorating.
2011
Assessment graphic from 2011 or 2016 showing the environment was in good condition, resulting in stable environmental values, but the situation was deteriorating.

Many of the native ecosystems remain intact, but are vulnerable to potential impacts of ongoing small-scale land-use change, invasive species pressures and extreme climate events.