Transplant Survivorship of Bryophyte Soil Crusts in the Mojave Desert

Patches of the dominant biological soil crust moss (Syntrichia caninervis) in the Mojave Desert were subjected to transplant experiments to test the survivability of crustal transplantation due to source or destination microhabitat. After a period of 27 months, all the reciprocally transplanted and replanted sections had survived. However, percent cover of the reciprocally transplanted patches declined 20–50% relative to initial cover compared to a decline in cover of 36–52% for the replanted patches. Similarly, shoot density declined an average of 26% in the transplants and replants. Shoot mortality was essentially negligible through the first 21 months of the study and then declining across all treatments to approximately 5–10 dead shoots/cm2. However, this shoot death was also observed in equivalent densities in the host patches, indicative of a community-wide decline in plant health that was probably related to a regional rainfall deficit over this period. A tendency existed for plants moved from a shaded site to have reduced shoot density in the new site, and plants moved into exposed sites lost significantly more cover than plants moved into shaded sites. These seemingly conflicting trends result from one of the transplant treatments, the shaded to exposed, exhibiting a greater loss in shoot density and decline in cover than its reciprocal transplant, exposed to shaded. For soil restoration of disturbed bryophyte crusts, we recommend using as source material both the exposed and the shaded portions of the crust but avoiding moving Syntrichia from a shaded site into an exposed site.