The Antarctic Ecosystem Inventory: A classification, descriptions and maps of Antarctica’s ice-free terrestrial ecosystems

Background: Antarctica, one of the least understood natural areas on Earth, is threatened by human disturbance and climate-related changes, underscoring the imperative for biodiversity inventories to inform conservation. Antarctic ecosystems support species and genetic components of biodiversity, ecosystem services and planetary stability. Here we present Antarctica’s first comprehensive ecosystem classification and maps of ice-free land, which hosts most of the continent’s documented terrestrial and freshwater biodiversity. We shaped a tiered approach using latent variables in a factor analysis to partitioned continental-scale abiotic variation, then biotic variation represented in spatial models, and finally recognised regional-scale variation among biogeographic units. This produced a spatially explicit classification with five environment types (tier 1), 31 habitats (tier 2) and 309 regional ecosystems (tier 3) mapped at 100 m resolution and aligned with ‘level 4’ of the IUCN global ecosystem typology. This first comprehensive ecosystem inventory will support the Antarctic Treaty’s Environmental Protocol with foundational data for identifying protected areas and tracking risks to Antarctic ecosystems. It’s tiered structure and workflow accommodate data scarcity and facilitate efficient updates which promoting robustness as knowledge builds.Summary of data submissionsThe Antarctic Ecosystem Inventory includes a hierarchical classification and maps for ice-free lands of Antarctica developed using methods described by Tóth et al. (in review). The purposes of the inventory are to support i) policy and management planning for biodiversity conservation under the Montreal Protocol of the Antarctic Treaty; and ii) the advance of ecological knowledge of Antarctic ecosystems and component biota.The classification includes three tiers.1) Major environmental units (Tier 1) represent major variations in environmental, climatic, and topographic conditions across the continent. Includes a folder containing the rasters of the predictor variable used to define the Tier 1 units (Abiotic Variables) and a raster of the level of confidence of the assigned classification. Folder: TIER 1 Major Environmental Units Files: Tier1_MEUs.tif (Geotiff); Tier1_MEUs.tif.vat.dbf (Values Attribute Table), Conf1.tif (Geotiff)SubFolder: Abiotic VariablesFiles: 10 Geotiffs (elevation_bm.tif, slope_bm.tif, rugosity_bm.tif, mean_wind_bm.tif, sum_rad.tif, MeanTemp_1415_bm.tif, Total_DD_1415_minus5_bm.tif, Total_Precip_1415_bm.tif, Melt_sum.tif and mean_cloud_bm.tif) and supporting files2) Habitat complexes (Tier 2) represent locally significant variations in the combined habitat suitability for a range of vertebrate, invertebrate, plant and other taxa. Includes a raster of the level of confidence of the assigned classificationFolder: TIER 2 Habitat ComplexesFiles: Tier2_HCs.tif (Geotiff); Tier2_HCs.tif.vat.dbf (Values Attribute Table), Conf2.tif (Geotiff)3) Bioregional ecosystem types (Tier 3) represent regional variants of Habitat complexes occurring in different Antarctic Conservation Biogeographic Regions (ACBRs), consistent with Level 4 units in the IUCN Global Ecosystem Typology (Keith et al., 2022). This level of classification serves as a proxy for regional turnover (gamma diversity) of biota.Folder: TIER 3 Bioregional ecosystem typesTóth, A.B., Terauds. A., Chown S.L., Hughes K.A., Convey P., Hodgson D.A., Cowan D.A., Gibson, J., Leihy. R.I., Murray N.J., Robinson, S.A., Shaw, J.D., Stark J.S., Stevens M.I., van den Hoff, J., Wasley J. and Keith, D.A. (2025). The Antarctic Ecosystem Inventory: A classification, descriptions and map of Antarctica’s ice-free lands. Scientific Data.