Optimizing production of nursery-based biological soil crusts for restoration of arid land soils Raw sequence reads. Optimizing production of nursery-based biological soil crusts for restoration of arid land soils

In order to optimize production, we followed growth dynamics of biocrusts from cold (Great Basin) and hot desert (Chihuahuan) sites. Peak biomass was attained between 3 and 7 weeks in cold desert biocrusts, and at 12 weeks in those from hot deserts. We also re-used the resultant biocrust inoculum to seed successive incubations, tracking both biomass production and cyanobacterial 16S rRNA community structure. Hot desert biocrusts showed little to no viability upon reinoculation, while cold desert biocrusts continued to grow, but at the expense of progressive shifts in species composition. This all leads us to discourage the reuse of nursery-grown inoculum. Surprisingly, growth was highly variable among replicates, and overall yields were low, a fact that we attribute to the demonstrable presence of virulent and stochastically distributed but hitherto unknown cyanobacterial pathogens. We provide recommendations to avoid pathogen incidence in the process.