Seedbank studies of Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) conclude that seed banks are transient, with little seed carry-over. Germination studies of mountain big sagebrush (Artemisia tridentata ssp. vaseyana) in a laboratory setting have shown evidence of seed dormancy.  These studies suggest dormancy in sagebrush may be subspecies-specific, but there is a lack of empirical field research verifying these conclusions. 

            Our objective was to investigate seed dormancy of both subspecies by tracking added seeds and sampling for seeds in situ.  We chose six sites in eastern Oregon, southern Idaho, northwestern Utah and eastern Nevada.  Ninety-eight nylon bags, each containing 100 seeds, were placed at each site during November 2006.  Seeds were placed on the soil surface in the open, on the soil surface beneath litter, and 3 cm below the soil surface to determine whether dormancy is affected by continued darkness or environmental conditions.  Subsets of seeds were evaluated to determine viability in late spring and autumn of 2007. 

            Bags were collected in April 2007 and intact seeds were tested for viability.  Initial viability of test seeds was 81% (vaseyana) and 92% (wyomingensis).  At the spring sampling, preliminary results across all sites indicated that both subspecies retained 30-35% viability of seeds that were in the open and under litter.  Viability of buried seeds was approximately 41% and 53% for ssp. vaseyana and ssp. wyomingensis, respectively.  This compares to approximately 48% and 90% viability of cold-stored ssp. vaseyana and ssp. wyomingensis control seeds, respectively.