Facilitating restoration of degraded biological soil crusts using mixed culture inoculation

• Published in: Journal of arid environments 2023-01, Vol.208, p.104876, Article 104876
• Main Authors: Reeve, Sharon, Palmer, Brianne, Cobb, Polina, Pietrasiak, Nicole, Lipson, David A.
• Format: Article
• Language: English
• Subjects: Biological soil crust; Coastal sage scrub; Microbial inoculation; Restoration
• ISSN: 0140-1963; 1095-922X
• DOI: 10.1016/j.jaridenv.2022.104876

In arid and semiarid ecosystems, the biological soil crust (biocrust) community is ecologically critical and it is advantageous to restore damaged biocrust. Coastal sage scrub (CSS) is a unique and imperiled valuable habitat. At present, studies of biocrust restoration in CSS habitat do not exist. This study examined the feasibility of isolating and culturing a mix of endemic CSS cyanobacteria and green algae to inoculate native CSS soil, thereby facilitating recovery of disturbed biocrust. To gauge whether inoculation increases soil function, we measured culture growth, chlorophyll a, extractable polysaccharides, and stability. Growth of biocrust organisms and increases in functionality were compared among three inoculation treatments (mixed culture, ground biocrust, and uninoculated control) with either autoclaved or non-autoclaved native soil to determine the extent that native crust organisms can regrow without inoculation. A novel genus and species of cyanobacteria was isolated and classified as Trichotorquatus maritimus. The mixed culture included a green alga, possibly Chlamydomonas callunae. Mixed inoculum added to non-autoclaved native soil significantly improved the soil functions. After two months, the mixed inoculum increased chlorophyll levels, soil stability, and increased extractable polysaccharides. It may be possible in the future to restore biocrust in CSS using mixed culture inoculation. •Biological soil crust inoculum from the coastal sage scrub can be used to restore soil function.•Biological soil crust inoculum performs better when it is a mixed culture of algae and cyanobacteria.•The isolation of new Cyanobacteria species (Trichotorquatus maritimus) from coastal sage scrub soils.