Full description
Citation: Valavi R, Levick SR, Lehmann EA, Liu N, Giljohann KM, Williams KJ, Collings S, Johnson S, Botha EJ, Munroe SEM, Van Niel TG, Newnham G, Paget M, Malley C, Carlile P, Gunawardana D, Lyon P, Richards AE, Tetreault Campbell S and Ferrier S (2025) HCAS 3.3 (1988-2024) base model estimate of habitat condition (90m grid), National Connectivity Index 2.0 (NCI) and annual time series for continental Australia. Data collection 65549. CSIRO, Canberra, Australia. DOI: https://data.csiro.au/collection/csiro:65549.The data collection utilises Geoscience Australia’s archive of Landsat Earth observation imagery over 37 years from 1988 to 2024, and comprises for continental Australia:
• the 90 m gridded (Australian Albers projection, EPSG 3577, Geographic Datum of Australia 1994) HCAS v3.3 base model (1988-2024) estimation of habitat condition for terrestrial biodiversity
• Annual epochs of habitat condition derived from 3-, 5- and 10-year rolling averages of remotely sensed ecosystem characteristics (condition variables) from 1990, 1992 and 1997 to 2024, respectively
• model-based uncertainty quantification as 95% confidence interval limit estimates of Habitat Condition for the long-term epoch (1988-2024) and selected short-term epochs, applying the method developed by Lehmann et al. (2025)
• classification of long- and short-term epochs of Habitat Condition into six modification levels based on experts’ best estimate of condition (Giljohann et al., 2024) for each category of the Vegetation Assets, States and Transitions (VAST) narrative framework (Thackway and Lesslie, 2006; 2008)
• National Connectivity Index (NCI) v2.0 (Giljohann et al., 2022) for the long-term epochs and short-term epochs using the corresponding HCAS v3.3 epoch
• long- and short-term epochs of Connectivity-adjusted Condition (NCIC) derived from the geometric mean of corresponding NCI and HCAS epochs
• several other datasets to support use and interpretation of the long- and short-term epochs of HCAS and NCI products, and related derivatives, including reference sites and the input remotely sensed ecosystem characteristics (i.e. Condition Variables).
HCAS v3.3 (production version 3) was derived using 'ClassicHCAS' software version 0.2.0 and 'HCAS-workflow' software version 1.2.1. The NCI and NCIC are developed by DCCEEW and included in the data collection along with other derivative products, for end user convenience. The NCI has been updated using HCAS v3.3 epochs.
Raster datasets (*.tif) are Cloud Optimised GeoTIFFs at 90 m grid resolution, GDA 1994 (Australian Albers, EPSG:3577).
HCAS v3.3 Habitat Condition indices vary continuously from a theoretical minimum of 0.0 (ecosystem integrity removed) to a maximum of 1.0 (ecosystem integrity in reference condition). NCI also ranges continuously from 0.0 (unconnected removed habitat) to a maximum of 1.0 (fully connected intact habitat), as does the NCIC: from 0.0 (landscape ecosystem integrity functionally extinguished) to a maximum of 1.0 (landscape ecosystem integrity functionally intact and in reference condition). Both the HCAS and NCIC represent the contribution that a given site (grid cell) makes to effective area of ecosystem integrity remaining within a spatial reporting unit, as a proportion of the contribution made by a site in reference condition.
Data extent is defined by any data pixel intersecting a coastline polygon as defined by the land fraction dataset (Liu 2024). The data and no-data extent of each grid layer encompasses the area within the Australian Continental Exclusive Economic Zone (EEZ) (Alcock et al., 2020), excluding territories of Cocos, Christmas, Norfolk, Macquarie, Heard, and McDonald Islands, as well as Antarctica (Liu and Newnham, 2024).
Data are described in "Habitat Condition Assessment System (HCAS) version 3.3: A guide to the 90-metre data collection. Technical report EP2025-2979" (available from CSIRO's publication repository, see related links).
Lineage: The HCAS v3.3 product suite was developed at 90 m grid resolution in Australian Albers projection (GDA 1994) using a combination of:
• 14 annualised time series of remotely sensed ecosystem characteristic variables, 1988 to 2024 (Levick et al., 2025), sourced from the Digital Earth Australia Surface Reflectance NBART Landsat Analysis Ready Data Collection 3 (Commonwealth of Australia, 2021) Derivative Products version 4.0.0 (Geoscience Australia, 2024; Lymburner, 2024)
• 58 environmental covariates selected from more than 120 'non-anthropogenic' candidates largely sourced from the Terrestrial Ecosystem Research Network (TERN) compilation (Malone et al., 2025; Searle, 2023) with additional custom variables developed by Liu et al. (2025)
• spatially inferred reference sites as training data (Giljohann et al., 2025b), sampled to represent the most intact remaining examples of Australia’s varied ecosystems and their environments (Valavi et al., 2025a)
• spatially inferred reference sites as benchmark data (Giljohann et al., 2025b), sampled to represent both remotely sensed ecosystem characteristic variables and their environments from among the most intact remaining examples of Australia’s ecosystems, with an emphasis on individual water bodies and protected area properties (Valavi et al., 2025a).
The HCAS v3.3 reference ecosystem model (REM) was developed using a generalised additive model (GAM) with 488,619 reference sites as training data, 46 environmental covariates (selected from 58), and 14 remotely sensed ecosystem characteristic variables summarised over 37 years (1988 to 2024). The REM was used in the HCAS v3.4 base model with the 1988 to 2024 long-term epoch and 590,342 benchmark reference sites. Short-term epochs for each of the 14 remotely sensed ecosystem characteristic variables were derived as 3-, 5- or 10-year antecedent rolling averages (the target year is the end year) utilising the time series (1988 to 2024). These processing steps are detailed in Valavi et al. (2025a).
Model-based uncertainty estimates were derived from more than 100 bootstrap runs applied to the sample of training and benchmark reference sites to derive 95% confidence interval limits (upper 97.5th percentile condition estimate and lower 2.5th percentile condition estimate and the 95% confidence interval width) for each 90x90m pixel of the long-term epoch (1988-2024), and selected 3-, 5-, and 10-year epochs.
All data products were derived using a 90m spatial grid in Australian Albers (GDA94 / Australian Albers).
The "Habitat Condition Assessment System (HCAS) version 3.3: A guide to the 90-metre data collection", accompanying this data collection (see related links), outlines how the HCAS v3.3 differs from the HCAS v3.1 (Valavi et al. 2025; Williams et al. 2025), and includes a general discussion of limitations of particular note, and a data quality statement.
This data collection also includes an update to the National Connectivity Index version 2.0 (NCI v2) base model using the corresponding HCAS v3.3 inputs. The NCI v2.0 method (Giljohann et al. 2022) has not changed, only the input condition data.
Technical reports provide details about the inputs, processing methods, outputs and uncertainty quantification, applied in developing HCAS version 3 series. For the latest publications see: https://research.csiro.au/biodiversity-knowledge/projects/hcas/. Contact us at [email protected] or [email protected].
Available: 2025-09-29
Data time period: 1988-01-01 to 2024-12-31
Subjects
95% confidence interval |
Accounting, Auditing and Accountability |
BCDEV |
BS10 |
BSI |
BSrange |
Commerce, Management, Tourism and Services |
Connectivity-adjusted Condition |
Conservation and Biodiversity |
EDEV |
Engineering |
Environmental Sciences |
Ecological Applications |
Environmental Assessment and Monitoring |
Environmental Management |
Environmental Management |
Geomatic Engineering |
HCAS |
Habitat Condition Assessment System |
Landsat |
Landsat derivative products Collection 4 |
Landscape Ecology |
NBR |
NCI |
NCIC |
NDMI |
NDWI |
NPV10 |
NPVrange |
National Connectivity Index |
PV10 |
PVrange |
Photogrammetry and Remote Sensing |
SDEV |
Sustainability Accounting and Reporting |
VAST |
biodiversity |
climate |
ecosystem condition |
ecosystem integrity |
epoch |
fractional cover |
geomad |
geomedian |
kNDVI |
landform |
limitation assessment |
lithology |
reference condition |
reference site |
remote sensing |
satellite |
soil |
spectral indices |
surface water |
terrestrial |
uncertainty quantification |
vegetation-assets-states-and-transitions |
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Identifiers
- URL : data.csiro.au/collection/csiro:65549
- Handle : 102.100.100/710206
- DOI : 10.25919/ZHFQ-1X80
