HCAS 3.0 (1988-2022) base model estimate of habitat condition (250m grid), National Connectivity Index (NCI) 2.0, 3-year average annually rolling epochs of HCAS and NCI from 1990 to 2022, trends and other derivatives for continental Australia

Please cite as follows: Valavi R, Williams KJ, Liu N, Levick S, Giljohann KM, Johnson S, Botha EJ, Munroe SEM, Lehmann EA, Collings S, Searle R, Van Niel TG, Newnham G, Paget M, Joehnk K, Hosack GR, Harwood TD, Malley C, Gunawardana D, Sivanandam P, Carlile P, Richards AE, Tetreault Campbell S, Schmidt RK and Ferrier S (2024) HCAS 3.0 (1988-2022) base model estimate of habitat condition (250m grid), National Connectivity Index (NCI) 2.0, 3-year average annually rolling epochs of HCAS and NCI from 1990 to 2022, trends and other derivatives for continental Australia. Data Collection 62484. CSIRO, Canberra, Australia. Landing page: https://data.csiro.au/collection/csiro:62484. \n \nThis data collection comprises, for continental Australia, the 250m gridded Habitat Condition Assessment System (HCAS) version 3.0 (1988-2022) base model (HCAS v3.0) estimation of habitat condition for terrestrial biodiversity, updated National Connectivity Index (NCI) v2.0 using the HCAS v3.0 base model, 3-year antecedent average rolling short-term epochs of HCAS, NCI, connectivity-adjusted condition (NCIC) and Ecosystem Site Condition (ESC) from 1990 to 2022, trends and other derivatives for continental Australia. The HCAS v3.0 short-term epochs are derived from the base model, and the NCI, NCIC and ESC short-term epochs use the corresponding HCAS v3.0 epochs as an input (production version 3-2). Several other datasets support use and interpretation of the base model, epochs and trends. \n\nSpatial raster datasets are provided in GeoTIFF format (*.tif) at 250m grid resolution, Geographic Datum of Australia (GDA) 1994 (Australian Albers, EPSG:3577). The original data, in a grid of 0.0025 degrees of latitude and longitude (EPSG:4283, GDA 1994), was projected to Australian Albers. Continuous data were bilinearly resampled resulting in some smoothing across pixels. Therefore, the unprojected data (EPSG:4283) are also provided as an option available to users. All GeoTIFFs are provided as Cloud Optimised GeoTIFFs (COGs). COGs are regular GeoTIFF files with an internal organisation to enable HTTP GET range requests to ask for just the needed parts of a file. In most cases, a corresponding *.png map image is also provided for quick views. \n\nThe HCAS v3.0 base model and epoch datasets are Habitat Condition indices that vary continuously from a theoretical minimum of 0.0 (ecosystem integrity removed) to a maximum of 1.0 (ecosystem integrity in reference condition). The same definition applies to Ecosystem Site Condition (ESC). The 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 (ecosystem integrity functionally extinguished) to a maximum of 1.0 (ecosystem integrity functionally connected and in reference condition). \n\nThe data extent of the curated projected collection is defined by any data pixel that intersected a coastline polygon using the land fraction dataset developed by Liu (2024) and the extent of National Land use data (ABARES, 2024b). The data and no-data extent of each grid layer encompasses the area within the Australian Continental Exclusive Economic Zone (EEZ), excluding territories of Cocos, Christmas, Norfolk, Macquarie, Heard, and McDonald Islands, as well as Antarctica (Liu and Newnham, 2024). \n\nThis HCAS v3.0 product suite substantially improves on and extends the former HCAS series 2 outputs. HCAS v3.0 uses 14 remotely sensed ecosystem characteristics derived from the Digital Earth Australia Surface Reflectance NBART Landsat Analysis Ready Data Collection 3 derivative products (Commonwealth of Australia, 2021). HCAS v3.1 supersedes HCAS v3.0. \n\nData descriptions are summarised in the accompanying "Habitat Condition Assessment System version 3.0: A guide to the 250-metre data collection" documentation, which can be downloaded separately from CSIRO's publication repository (see related links).\nLineage: The HCAS v3.0 product suite was developed at 0.0025° grid resolution (9 arcsecond, unprojected spatial reference system EPSG:4283, approximately 250m) using a combination of:\na) Fourteen annualised time series of remotely sensed ecosystem characteristic variables, 1988 to 2022, sourced from the Digital Earth Australia Surface Reflectance NBART Landsat Analysis Ready Data Collection 3 derivative products (Commonwealth of Australia, 2021);\nb) 56 environmental covariates selected from more than 120 'non-anthropogenic' candidates;\nc) Spatially inferred reference sites as training data sampled to represent the most intact remaining examples of Australia’s varied ecosystems and their environments;\nd) Spatially inferred reference sites as benchmark data sampled to represent both remotely sensed ecosystem characteristic variables and their environments from among the most intact remaining examples of Australia’s ecosystems.\n\nThe HCAS v3.0 reference ecosystem model was developed using a generalised additive model (GAM) with 257,307 reference training sites, 56 environmental covariates, and 14 remotely sensed ecosystem characteristic variables summarised over 35 years (1988 to 2022). The base model was developed using the 1988–2022 long-term epoch and 433,575 reference benchmark sites. Short-term epochs for each of the 14 remotely sensed ecosystem characteristic variables were derived as 3-year antecedent rolling averages (the target year and the two prior years), 1990 to 2022 (33 epochs). \n\nAll data products were derived using a 0.0025° grid (EPSG:4283, GDA94). Datasets were subsequently projected to a 250 x 250 m geographic grid in Australian Albers (EPSG:3577, GDA94) using bilinear resampling for continuous data and neighbourhood mode or nearest for ordinal or categorical data, respectively. \n\nThe "Habitat Condition Assessment System version 3.0: A guide to the 250-metre data collection" documentation, accompanying this data collection (see related links), outlines how the HCAS v3.0 differs from the HCAS v2.3 (Harwood et al., 2023; Williams et al., 2023a). \n\nThis data collection also includes an update to the National Connectivity Index version 2.0 method (NCI v2) base model and time series using the corresponding HCAS v3.0 inputs. The NCI method has not changed, only the input condition data. \n\nTechnical reports (forthcoming, mid-2025) provide details about the inputs, processing methods, outputs and uncertainty quantification, applied in developing HCAS version series 3. For the latest publications see: https://research.csiro.au/biodiversity-knowledge/projects/hcas/.

引用格式如下：Valavi R、Williams KJ、Liu N等（2024）。澳大利亚大陆生境状况评估系统3.0（HCAS 3.0，1988-2022）基础模型生境状况估算结果（250米格网）、国家连通性指数2.0（NCI 2.0）、1990-2022年HCAS与NCI的3年滚动年均值序列、澳大利亚大陆生境状况趋势及其他衍生数据集。数据集编号62484。澳大利亚联邦科学与工业研究组织（CSIRO），堪培拉，澳大利亚。数据访问页面：https://data.csiro.au/collection/csiro:62484。

本数据集面向澳大利亚大陆，包含以下内容：250米格网化的陆地生物多样性生境状况评估系统3.0（HCAS 3.0，1988-2022）基础模型生境状况估算结果、基于HCAS 3.0基础模型更新的国家连通性指数2.0（NCI 2.0）、1990-2022年HCAS、NCI、连通性校正生境状况（NCIC）与生态系统站点状况（ESC）的3年前期滚动短时序列，以及澳大利亚大陆生境状况趋势与其他衍生数据集。其中HCAS 3.0短时序列由基础模型衍生而来，NCI、NCIC及ESC的短时序列以对应HCAS 3.0序列作为输入（生产版本3-2）。另有多款辅助数据集可用于本数据集基础模型、序列与趋势结果的应用与解读。

空间栅格数据集以GeoTIFF格式（*.tif）提供，格网分辨率为250米，采用澳大利亚大地基准1994（GDA 1994）的澳大利亚阿尔伯斯投影（EPSG:3577）。原始数据采用0.0025度经纬度格网（EPSG:4283，GDA 1994），后被投影至澳大利亚阿尔伯斯坐标系。连续型数据通过双线性重采样处理，会在像素间产生一定程度的平滑效果。因此，我们同时为用户提供未投影的原始数据（EPSG:4283）作为可选方案。所有GeoTIFF文件均采用优化云存储GeoTIFF（COGs）格式：该格式为标准化GeoTIFF文件，内部结构支持HTTP范围请求，仅下载文件所需的部分内容。多数情况下，数据集还附带对应的*.png预览地图，方便快速查看。

HCAS 3.0基础模型与序列数据集为连续型生境状况指数，理论取值范围为0.0（生态系统完整性完全丧失）至1.0（生态系统完整性处于参考状态）。生态系统站点状况（ESC）采用相同的取值定义。国家连通性指数（NCI）的取值范围同样为0.0（连通性丧失的退化生境）至1.0（完全连通的原生完整生境）；连通性校正生境状况（NCIC）则为0.0（生态系统完整性功能上完全丧失）至1.0（生态系统完整性功能上连通且处于参考状态）。

经整理的投影数据集范围由以下两部分确定：一是基于Liu（2024）开发的陆面占比数据集，与海岸线多边形相交的所有数据像素；二是国家土地利用数据集（澳大利亚农业与资源经济科学局，2024b）的覆盖范围。每个栅格图层的有效数据与无数据范围均涵盖澳大利亚大陆专属经济区（EEZ）内的区域，但不包括科科斯群岛、圣诞岛、诺福克岛、麦夸里岛、赫德岛和麦克唐纳群岛以及南极洲的领地（Liu与Newnham，2024）。

本HCAS 3.0产品套件在原有HCAS 2系列数据集的基础上实现了大幅改进与扩展。HCAS 3.0采用了14项遥感生态系统特征变量，这些变量源自澳大利亚数字地球地表反射率NBART Landsat预分析数据集合3衍生产品（澳大利亚联邦政府，2021）。HCAS 3.1版本已取代HCAS 3.0。

数据集的详细说明已汇总至配套文档《生境状况评估系统3.0：250米格网数据集指南》，该文档可从CSIRO的出版物仓库单独下载（详见相关链接）。

数据溯源：HCAS 3.0产品套件以0.0025°格网分辨率（9角秒，未投影空间参考系统EPSG:4283，近似250米）开发，所用数据源包括：
a）1988-2022年共14项年度化遥感生态系统特征变量时间序列，源自澳大利亚数字地球地表反射率NBART Landsat预分析数据集合3衍生产品（澳大利亚联邦政府，2021）；
b）从120余项“非人为干扰”候选变量中筛选出的56项环境协变量；
c）空间推断的参考站点作为训练数据，采样自澳大利亚各类生态系统及其生境中保存最完好的样本；
d）空间推断的参考站点作为基准数据，采样自澳大利亚生态系统中保存最完好的样本，涵盖遥感生态系统特征变量及其生境环境。

HCAS 3.0参考生态系统模型采用广义加性模型（GAM）构建，共使用257307个参考训练站点、56项环境协变量以及1988-2022年35年间汇总的14项遥感生态系统特征变量。基础模型基于1988-2022年长时间序列与433575个参考基准站点开发。14项遥感生态系统特征变量的短时序列以1990-2022年的3年滚动前期均值（目标年份及前两个年份）衍生得到，共包含33个序列。

所有数据产品均以0.0025°格网（EPSG:4283，GDA94）为基础生成。后续将数据集投影至250×250米的澳大利亚阿尔伯斯地理格网（EPSG:3577，GDA94）：其中连续型数据采用双线性重采样，有序分类或分类数据则分别采用邻域众数采样或最近邻采样。

本数据集配套的《生境状况评估系统3.0：250米格网数据集指南》文档（详见相关链接），详细说明了HCAS 3.0与HCAS 2.3版本（Harwood等，2023；Williams等，2023a）之间的差异。

本数据集还包含对国家连通性指数2.0（NCI 2.0）方法的更新：基于对应HCAS 3.0输入数据，更新了NCI 2.0的基础模型与时间序列。NCI的计算方法未发生改变，仅更新了输入的生境状况数据。

关于HCAS 3系列开发过程中所用的输入数据、处理方法、产出结果与不确定性量化的详细信息，将在2025年中期发布的技术报告中说明。最新研究成果可访问：https://research.csiro.au/biodiversity-knowledge/projects/hcas/。