Advancing studies on global biocrusts distribution

Abstract. Biological soil crusts (biocrusts hereafter) cover a substantial proportion of dryland ecosystem and play crucial roles in ecological processes such as biogeochemical cycles, water distribution and soil erosion. Consequently, studying the spatial distribution of biocrusts holds great significance for drylands, which is still lacking, especially in a global scale. This study aimed to stimulate global-scale investigations of biocrusts distribution by introducing three major approaches: spectral characterization indices, dynamic vegetation models, and geospatial models, while discussing their applicability. Then, we summarized present understandings of biocrusts distribution. Finally, to further advance this field, we proposed several potential research topics and aspects, including building standardized database of biocrusts, enhancing non-vascular vegetation dynamic models, integrating multi-sensor monitoring, making full use of machine learning, and focusing on regional research co-development. This work is supposed to significantly contribute to mapping biocrusts distribution, and thereby to advance our understandings of dryland ecosystem management and restoration.