Restoration of degraded loess surfaces by cyanobacterial biocrusts: strategies for enhancing their development

Abstract

Loess landscapes are highly susceptible to erosion by wind and water, presenting serious environmental and public health challenges. In these degraded environments, complex microbial communities of biocrusts stabilize the substrate and play a crucial ecological role, particularly where the growth of vascular plants is limited. Cyanobacteria, as key biocrust-forming organisms, have shown considerable potential in dryland restoration efforts. However, their effectiveness is often constrained by the harsh conditions typical of arid and semi-arid regions. This study aimed to evaluate the potential of loess-derived cyanobacterial strains ( Nostoc sp. L5 and Nostoc sp . L6) to promote biocrust formation and to investigate strategies for enhancing biocrust development by examining the effects of watering regimes and the application of the algal-based biostimulant FerWay. Biocrust development was assessed through visual monitoring and quantified by measuring chlorophyll a and total carbohydrate contents. Both strains successfully established biocrusts under examined watering conditions, with higher watering frequency consistently promoting greater chlorophyll a and carbohydrate accumulation. The application of FerWay showed a strain- and moisture-dependent effect, significantly enhancing biomass in Nostoc sp. L6 under high watering frequency. These findings emphasize the need for strain-specific and environmentally tailored strategies in biocrust restoration and highlight the potential of loess-derived cyanobacterial strains for sustainable land rehabilitation.