The Biodiversity Habitat Index (BHI) has been developed by CSIRO (Australia’s national science agency), working in partnership with GEO BON, GBIF, Map of Life and the PREDICTS project. This indicator is intended to add value to existing assessments of the “rate of loss [and degradation and fragmentation] of all natural habitats, including forests”, under Aichi Target 5, by translating the observed spatial distribution of habitat loss and degradation into expected impacts on retention of terrestrial biodiversity.

This assessment is performed using a fine-scaled grid covering the entire terrestrial surface of the planet. For each cell in this grid an estimate is derived of the proportion of habitat remaining across all cells that are ecologically similar to this cell of interest. Ecological similarity between cells is predicted as a function of abiotic environmental surfaces (describing climate, terrain, and soils) scaled using generalised dissimilarity modelling to reflect observed patterns of spatial turnover in species composition, based on best-available occurrence records for plants, vertebrates and invertebrates globally. The BHI for any given spatial reporting unit (e.g. IPBES region, country) is then derived as a weighted geometric mean of the scores obtained for all cells within that unit, with the contribution of each cell weighted according to its ecological uniqueness. This aggregate score therefore indicates the proportional retention of habitat across finely-mapped environments supporting relatively distinct assemblages of species within a given reporting unit.

While results for the BHI were initially generated for forest biomes only, using data on forest loss from the Global Forest Change dataset, this coverage has now been expanded to cover all terrestrial biomes across the planet. This has been achieved through use of CSIRO’s statistically downscaled land-use dataset.