Assessing the implementation of crustivoltaics in <i>trans</i> for the restoration of biological crust cover in remote sites

ABSTRACT While biocrust restoration has gained relevance to combat increasing dryland soil degradation during the last decade, its scalability and ecological effectiveness remain limited because of the difficulty in producing large amounts of well-adapted, site-specific biocrust inoculum. Crustivoltaics, an approach where existing, local photovoltaic plants are used as large-scale microbial nurseries to produce biocrust inoculum, has been developed to overcome these barriers. Still, many degraded sites are in remote areas devoid of local solar farms. Here, we tested if crustivoltaics could be operated in a “ trans ” mode to generate compositionally appropriate inoculum for edaphically distinct or geographically distant sites. We assessed whether a facility in the Sonoran Desert built on sandy soils could be used to produce high-quality inoculum for a Chihuahuan Desert restoration target with gypsic soils, the sites having compositionally distinct native biocrusts. We transplanted target soils over native host soils, monitoring biocrust recovery for 16 months. Biocrusts developed on the transplanted soils grew at rates similar to those on native soil controls (0.70 ± 0.16 mg Chl a m −2 month −1 ), but only when left uninoculated. Their resulting microbial communities, however, did not faithfully resemble those native to the distant site. Instead, new biocrusts were compositionally intermediate between native and host sites, as a result of environmental filtering and community reshaping. Our study shows that while trans-crustivoltaics is possible in terms of the quantity of inoculum produced, it may be suboptimal in terms of quality if edaphic matching is not considered. IMPORTANCE Increasing anthropogenic stress and climate change in dryland ecosystems have led to reduced soil fertility and increased dust emissions, which can affect human health. Because biological soil crusts help stabilize soils and maintain ecosystem function, they can be used to restore degraded dryland soils, where using solar power infrastructure as microbial nurseries to grow biocrust (crustivoltaics) is a promising strategy to scale up restoration. However, such infrastructure is not always available near degraded sites. In this study, we explore a trans-crustivoltaics approach, in which a solar facility is used to grow biocrust transplanted from a distant site to be restored. If successful, trans-crustivoltaics could expand the reach of biocrust restoration efforts.