Climate change could shift the geographical distribution of biocrusts in the Qaidam Basin

Abstract Biocrusts are widespread in global drylands and play vital roles in regulating soil properties and enhancing terrestrial ecosystem multifunctionality. However, their spatial distribution patterns and cover at regional scales are poorly understood, particularly in non‐hotspot regions such as the isolated Qaidam Basin, which is characterized by an arid to hyper‐arid climate, alpine desert ecosystem, and limited accessibility. This gap poses significant challenges for understanding biocrust dynamics, their contributions to ecosystem functioning and their conservation strategies. We surveyed 108 sites across the Qaidam Basin (~275,000 km 2 ) using a near‐grid sampling design to assess biocrust presence and cover, and we then combined the survey data with environmental factors to model biocrust distribution and project climate‐driven shifts at a 90 m resolution using a Random Forest model. Our results showed that biocrusts currently cover 12.4% of the Qaidam Basin on average, with cyanobacterial, lichen and moss‐dominated biocrusts occupying 2.0%–5.5%, primarily along the eastern and southern edges. Biocrust cover is primarily driven by precipitation and vegetation patterns. By the year 2050, climate change is projected to cause a small net decline in biocrust cover (1.0%–2.0%) but to drive a major distribution shift. The basin periphery is likely to experience a widespread biocrust degradation due to warming and drying, with coverage reduced by 8.2%–8.7%, while biocrust cover in the central‐eastern zones is projected to increase by 14.1%–15.4% due to increased precipitation. Synthesis and applications . Our high‐resolution biocrust maps establish a baseline for biocrust monitoring, management and assessment in the Qaidam Basin. The results underscore the importance of considering spatial heterogeneity in biocrust distributional shifts under climate change and implementing adaptive protection and restoration strategies. We recommend prioritizing the conservation of areas projected to experience biocrust decline by expanding existing reserve boundaries, while promoting recovery in regions with favourable future conditions through targeted inoculation techniques. Our study provides key insights for the evaluation and conservation of biocrusts across global dryland ecosystems.