Climate and soil texture collaboratively shape important components of biocrust soil carbon cycling globally

Purpose Biocrusts play an important role in regulating the carbon (C) cycle of terrestrial ecosystems. However, there have been few systematic assessments of the important components of the soil C cycling under biocrust cover. Materials and methods Hence, we conducted a meta-analysis of soil organic C (SOC), microbial biomass C (MBC), and soil respiration ( R s ) under biocrust cover using 437 independent observations from 89 studies throughout the world over the past 40 years (1980–2020) to systematically assess the effects of biocrusts on key components of C cycling in terrestrial ecosystems. Results and discussion Our results showed that biocrust cover increased SOC, MBC, and R s by 98%, 176%, and 35%, respectively, compared to uncrusted soil. The effects of biocrust on important components of soil C cycling depended on biocrust type, climatic condition, and soil texture. The positive effects of moss crusts on SOC (129%), R s (45%), and MBC (197%) were all stronger than those of cyanobacterial crusts (33%–131%). Elevation, annual potential evapotranspiration, and soil particle composition were identified as the main drivers of variation in SOC, MBC, and R s under biocrust cover. Conclusion Our study systematically assessed the effects of biocrust cover on important components of soil C cycling in terrestrial ecosystems globally, which is important for accurately predicting the contribution of biocrusts to the terrestrial ecosystem C balance in future climate change.