Moss biocrusts buffer the negative effects of karst rocky desertification on soil properties and soil microbial richness

Background and aims Karst rocky desertification (KRD), a land degradation form which is widespread but unique to karst ecosystems, has become an ecological disaster in southwest China. Biocrusts play crucial roles in many ecological processes of the degraded ecosystems. However, little is known about the effects of biocrusts on soil properties and soil microbial communities in the progression of KRD. Methods We sampled soil beneath moss biocrusts and bare soil in four grades of KRD (none, light, moderate, and severe) to compare soil nutrients, soil microbial diversity, community composition, structure, and networks across the range of KRD progression. Results Moss biocrusts had a positive effect on all soil nutrients and buffered the negative effects of KRD progression compared to bare soil. Moss biocrusts significantly increased soil microbial richness but had little contribution to diversity and community composition. Both soil bacterial and fungal communities were significantly correlated with total and available phosphorus, total potassium, soil temperature, slope, and altitude. Soil bacterial and fungal communities showed different sensitivities and strategies in face of environmental degradation in KRD-affected ecosystems. Conclusions Moss biocrust restoration could be used as a supplementary method in promoting ecological restoration in areas undergoing KRD due to their positive effects on soil nutrients and soil microbial richness. Our findings filled a knowledge gap pertaining to the microbial ecology of biocrust in regions experiencing KRD.