DOI: 10.25919/nkjf-f088
title: 9 arcsecond gridded HCAS 2.1 (2001-2018) base model estimation of habitat condition for terrestrial biodiversity, 18-year trend and 2010-2015 epoch change for continental Australia

description: This data collection comprises, for continental Australia, 9-arcsecond gridded HCAS version 2.1 (2001-2018) base model (v2.1) estimation of habitat condition for terrestrial biodiversity, an 18-year condition trend derived from annual epochs, two 10-year epochs ending 2010 and 2015 respectively, the epoch change for 2010-2015, and a series of ancillary datasets to support their use. This HCAS version 2.1 (v2.1) product suite comprises 19 datasets of which 17 are 9 arcsecond raster datasets covering continental Australia. All raster datasets are in GeoTIFF format (*.tif) at 0.0025° resolution (approx. 250 m grids), GDA 1994 datum. The HCAS v2.1 base model dataset describes natural habitat condition for native biodiversity applicable to the assessment period, 2001 to 2018, with scores ranging from 0.0 (habitat completely removed) to 1.0 (habitat in reference condition), being the ‘best’ estimate possible using the current HCAS implementation. The over-arching framework for the method was published in an internationally peer-reviewed scientific journal by Harwood et al. (2016) and has since been incrementally improved through two trial implementations (HCAS 2.0 beta – Williams et al. 2020, and this version HCAS 2.1 – Williams et al. 2021.). The 19 datasets in this collection: A. HCAS results – the base model and two 10-yr epochs (3 datasets): 1. HCAS v2.1 (2001-2018) base model. Developed using 18 years of remote sensing data to provide the HCAS ‘best estimate’ of habitat condition for that period. 2. HCAS v2.1 (2001-2010) epoch. HCAS ‘derived estimate’ of habitat condition for that 10-year period. 3. HCAS v2.1 (2006-2015) epoch. HCAS ‘derived estimate’ of habitat condition for that 10-year period. B. Trend and epoch condition change (6 datasets): 1. HCAS v2.1 (2001-2018) condition trend, standard error and masked significant trend for the 18-year assessment period. 2. HCAS v2.1 (E2010-E2015) change in habitat condition between the derived estimates of habitat condition for the two 10-year epochs, standard error of the difference in their interannual means, and masked significant change in habitat condition between epochs. C. Partial measures of uncertainty for aspects of the base modelling framework (4 datasets): 1. HCAS v2.1 (2001-2018) Standard error of the interannual mean over 18 years of annual fluctuations in estimated departures of remote sensing characteristics of a test site of interest from those of environmentally similar reference sites. 2. HCAS v2.1 (2001-2018) Distance in kilometres from a test site to any nearest reference site. 3. HCAS v2.1 (2001-2018) Predicted environmental distance from a test site to any most environmentally similar reference site within 200km. 4. HCAS v2.1 (2001-2018) A relative index of certainty that integrates how ‘nearby’ and how relevant were the 20 reference sites that were used as benchmarks to estimate each pixel’s condition. D. Masks to support appropriate use and interpretation of HCAS products (3 datasets): 1. HCAS v2.1 mask used in developing the product suite 2. HCAS v2.1 mask plus lakes mask – additional surface water areas from consideration when using the product suite or applying area-based summary statistics 3. HCAS v2.1 mask plus lakes plus plantations mask – to additionally exclude surface water areas and plantations from consideration when using the product suite or applying area-based summary statistics E. Reference sites used in developing HCAS v2.1 product suite (3 datasets): 1. HCAS v2.1 inferred reference condition sites (method as detailed in Williams et al. 2020 for HCAS v2.1) 2. HCAS v2.1 reference condition sites – training sample 3. HCAS v2.1 reference condition sites – benchmark sample