What is the NSW Habitat Intactness (HI) Index?

The NSW Habitat Intactness (HI) Index is an estimate of terrestrial habitat intactness relative to an estimated natural, unmodified and intact state. The index potentially ranges from areas where habitat remains relatively intact and unmodified (HI = 1.0), through to areas where natural habitat has been completely removed or replaced (HI = 0.0). Intact habitats provide the resources native species need to persist, as individuals and together as populations and ecosystems, and allows them to adapt to changes in their environment or respond to threats. Habitat that remains relatively intact and well-connected is expected to support a greater proportion of its original or potential diversity, thereby contributing to the integrity and resilience of ecosystems and the persistence of biodiversity.

How are the data created?

The NSW HI Index combines direct measures of remotely sensed vegetation cover with measures inferred from a range of relevant data sources. Inputs are synthesised using expert understandings of what each input provides and the quality of its data. In some instances, habitat characteristics can be directly measured, such as the loss of natural vegetation cover using remotely sensed products. In other cases, characteristics are only inferred from available proxy information. The NSW HI Index has been developed in the context of scarce, incomplete and constantly evolving data availability and the reliability of the model will vary across space, spatial scales, environments and the habitat characteristics present at any location.

What data are available?

Data are initially available annually from 2017, currently with a two-year time lag for the most recent layer due to the availability of the relative persistent green cover metric. Data for other periods may be generated as needed. The model provides a near-complete statewide estimate of habitat intactness but is limited by the data available at the time of each assessment, and its accuracy, currency and completeness.

Data details:

• Data type: raster, GeoTIFF, 32bit floating point
• CRS: EPSG:3577 - GDA94 / Australian Albers
• Pixel size: 90 x 90m
• Pixel values: 0.0 (lowest HI) to 1.0 (highest HI)
• Null value: -9999

What can the data be used for?

The NSW Habitat Intactness (HI) Index currently underpins the Biodiversity Indicator Program’s ecological condition of terrestrial habitat indicator that is reported in the NSW Biodiversity Outlook Report. The NSW HI Index is the primary spatial input to the NSW Neighbourhood Habitat Intactness (NHI) Index and the NSW Habitat Link Value (HLV) Index which currently underpin the Biodiversity Indicator Program’s ecological carrying capacity and ecological connectivity indicators respectively.

The NSW HI Index has supported state and regional biodiversity assessments including regional conservation initiatives, habitat connectivity, native vegetation management and threatened species assessments. It has also been used for assessing climate change risks and adaptation opportunities for ecosystem and species level diversity under the NSW adaptation strategy. The index has helped to inform NSW Saving our Species investment in landscape managed species. It can be used to assess ecological costs or benefits of alternative management actions in terms of biodiversity outcomes. It is expected that the NSW HI Index will continue to be developed and utilised in a broadening range of applications.