CrustThick: a biocrust thickness dataset (review version)

<i>Geographic coordinates in this review version have been generalized to integer degrees to protect sensitive site locations. Precise coordinates will be released upon publication.</i><b>Motivation: </b>As a self-organising principle and land-atmosphere interface, biological soil crusts (biocrusts) are fundamental components of dryland ecosystems, regulating hydrological processes, stabilising soil surfaces, and enhancing nutrient accumulation. Despite their ecological importance, the physical structure of biocrusts—particularly thickness—remains poorly quantified due to a lack of thickness data, which substantially limits our ability to conduct cross-regional comparisons and incorporate this key characteristic into ecosystem models. This is particularly true in the context of global change. Therefore, this study compiled the first dataset of biocrust thickness.<b>Main Types of Variables Included:</b> Geographic information, biocrust type, cover and thickness, habitat, sampling year and source.<b>Spatial Location and Grain:</b> Northern China drylands; point-based records from transect surveys and fixed-site observations.<b>Time Period and Grain:</b> 2004–2024; single-event or short-term surveys.<b>Major Taxa and Level of Measurement:</b> Cyanobacteria, moss and lichen crusts (mm-scale thickness); partial records also include habitat vegetation cover (herbaceous, shrub).<b>Software Format: </b>`.csv` files with metadata.