Biocrusts represent highly diverse communities formed by intimate associations between photoautotrophic organisms (i.e., cyanobacteria, algae, lichens, and bryophytes) and heterotrophic microorganisms inhabiting the uppermost millimeters of soil, where they form a thin, cohesive living layer. Although often overlooked, biocrusts cover nearly 12% of soils worldwide and play a pivotal role in regulating ecological processes that underpin ecosystem functioning and the provision of ecosystem services. Increasingly recognized as ecosystem engineers, biocrusts regulate the physical, chemical, and biological properties and processes of soils. Yet, their contribution to key ecosystem and Earth-system processes remains poorly quantified, and we still lack an integrated understanding of how processes operating at microbial and organismal scales scale up to influence ecosystem functioning and global change.
In this session, we invite contributions addressing the biodiversity, functioning, and ecological roles of biocrusts across spatial, temporal, and organizational scales, from microbial processes and organismal interactions to ecosystem and global processes. We welcome studies investigating biocrust effects on biogeochemical, carbon, nutrient, and water cycles; energy and surface–atmosphere exchanges; soil development, mineral weathering, erosion and dust emissions; geomorphological processes; biodiversity and species interactions; vegetation dynamics; and ecosystem stability, degradation, and restoration. We particularly encourage contributions exploring the responses, resilience, thresholds, and feedbacks of biocrusts under climate and other global changes, as well as their consequences for ecosystem functioning and large-scale environmental dynamics. Studies combining field and laboratory observations with experimental approaches, remote sensing, modelling, and other approaches to upscale biocrust processes across spatial and temporal scales are also encouraged.