COS 87-9
Rapid cultivation of desert mosses as a biological soil crust restoration material
Desert mosses are often overlooked as an important component of desert and biological soil crusts (biocrust) ecosystems, yet they provide key ecosystem services, including soil stabilization, water retention, carbon fixation, and house N-fixing cyanobacteria on their leaves. They respond extremely rapidly to precipitation and are able to survive long periods of no water, shifting from a dormant, and desiccation tolerant state, to active photosynthesis in a matter of seconds. With these qualities, desert mosses have the potential to be an excellent desert restoration material. Our goal was to determine the best methods to cultivate Syntricia caninervis and S. ruralis, common, and abundant species in the western deserts, collected from Hill AFB near Tooele, Utah. We washed, dried and crumbled mosses, adding about 4% total surface area of one moss species to pots containing sterile sand. In a full factorial design, pots were watered from below to the saturation point continuously for 5, 4, 3, or 2 days, and given a full nutrient suite (Knop’s solution) once at the beginning, monthly or biweekly, or not at all (n=6). Using a mixture of percent cover and modified NDVI photography, we quantified growth and turnover over four months.
Results/Conclusions
Moss biomass increased six-fold for both species in four months and grew best with monthly fertilizer. S. caninervis (the more drought-tolerant species) preferred 2-3 days of hydration, whereas S. ruralis (found in more mesic conditions), preferred 4-5 days hydration. Remarkably, we also cultivated a variety of other important biocrust organisms, including 4 genera of cyanobacteria, and 5 species of lichens. All were most common in S. caninervis pots, likely because this species grows very close to the ground surface, making it difficult to clean away all soil. The cyanobacterial community showed interesting patterns in turnover, with Microcoleous spp. (~8% maximum cover) dominating early, and Nostoc spp. (~85%) dominating after month two. We also witnessed an increase in Scytonema spp. (~8%) after month three, along with a marked increase in lichen cover (~4%). All cyanobacteria grew better in S. caninervis pots, with 3-5 days hydration and biweekly fertilizer, whereas lichens showed no water/fertilizer preferences. Our results indicate that we can target and cultivate not only desert mosses, but also many biocrust organisms of interest by optimizing growing conditions. These results have great potential for scaling-up as a desert inoculum source.