Plot data Mc Nemar: To enable comparisons with the 1961 and 2004 survey results, the Lambert Conformal Conic projection from the 2004 survey was used to precisely georeference and trim the RGB image across a 1-m2 grid, generating a total of 3,458 1-m2 grid cells. For each grid cell moss, lichen, or algae/cyanobacteria cover was extracted as one of the four cover classes: Heavy (>40%), Patchy (10–40%), Scattered (less than 10%), and None (0%) for the survey years 1962, 2004 and 2018. Ground truthing: To test the overall accuracy of cover classifications and ensure consistency with 2004 survey methodologies, a ground-truthing approach was performed. Photographs were taken of individual cells along eight transects, running west to east across the plot at 0.5, 1.5, 15.5, 16.5, 28.5, 29.5, 116.5 and 117.5 m distance from the NW corner. Each grid cell could be identified individually with an x/y coordinate in the centre and was surrounded by a rectangular frame parallel to the outer edge of the plot. A total of 174 photographs were taken and archived with Antarctica New Zealand. For each photographed grid cell, the presence of each functional group of vegetation and their cover class was assessed visually. Orthomosaic image: Aerial images were obtained using a DJI Matrice 600 Pro hex-rotor remotely piloted aircraft system equipped with a Canon EOS 5Ds camera (image size: 8688×5792 pixels, focal length: 50 mm, pixel size: 4.14 μm) on November 28, 2018. The flight altitude was 30 m above ground level, and a total of 10 ground-control points were included to provide accurate geo-referencing. An orthomosaic photo and accompanying DEM was generated with the acquired aerial images using Agisoft PhotoScan (now known as Metashape by Agisoft LLC, https://www.agisoft.com/) RELATED PUBLICATION: https://doi.org/10.1029/2022EF002823 GET DATA: https://doi.org/10.7488/ds/3417

The New Zealand Terrestrial Antarctic Biocomplexity Survey (nzTABS) is the largest and most comprehensive interdisciplinary landscape-scale study of terrestrial biology ever undertaken in Antarctica, incorporating fieldwork of 1500+ person days in 6 of the Dry Valleys (total area of 6500 km2), strategic sampling of over 1200 sites designed to encompass the landscape heterogeneities in the ecosystem, and a range of high-resolution remote sensing data. All samples were collected during the month of January in each sampling year. Initially a 220 km2 study area, consisting of Miers, Marshall, and Garwood Valleys as well as Shangri-La, was divided into more than 600 geographically and geologically distinct ice-free sectors (hereinafter “tiles”) using remote-sensing data and published soil maps. Tile boundaries were delineated where the combination of geographical and geological variables changed, and on-the-ground assessments were carried out in November 2008 to confirm the reliability of delineations. 554 tiles were chosen for sampling to encompass the entire range of geographical and geological heterogeneity. Sampling of soils and biological communities was carried out over two successive austral summers (January 2009 and January 2010). Surveys were conducted for vegetation (i.e., mosses, lichens, algal and cyanobacterial mats), lithic microbial communities, and invertebrates at each sampling site (verified by GPS to be inside its respective tile), followed by collection of bulk soil samples for additional analyses, including molecular analyses of bacteria (total and cyanobacteria-only) and fungi. In addition, a number of key variables were derived from satellite imagery, including surface soil temperature, a topographically derived ‘wetness index’, and distance to the coast. After quality control, data for 490 samples were included in the analysis. These data represent geochemistry and geomorphology to population genetics and microbial ecology parameters. Further details are provided at https://doi.org/10.1038/s42003-018-0274-5. Please cite the data with the following citation: Lee, C.K., Laughlin, D.C., Bottos, E.M. et al. Biotic interactions are an unexpected yet critical control on the complexity of an abiotically driven polar ecosystem. Commun Biol 2, 62 (2019). https://doi.org/10.1038/s42003-018-0274-5