Kristen Hasenstab-Lehman, C. Matt Guilliams, Santa Barbara Botanic Gardens
Dithyrea maritima (Davidson), or beach spectaclepod, is a dune specialist endemic to coastal dunes from central California, United States, to northwestern Baja California, Mexico. Individuals of this perennial herb spread by rhizomes, forming a diffuse colony of ramets, each terminating in rosette of 1 to several fleshy leaves, and a two-chambered fruit (silicle). It is listed on the California Native Plant Society Rare and Endangered Plant Inventory on list 1B.1 and was listed as Threatened under the California Endangered Species Act. Studied occurrences of the self-incompatible D. maritima have low seed set, though manual outcrosses boost seed production. Knowledge of the distribution of genotypes on the landscape is be a critical first step toward any number of recovery actions. In this study, we sample from approximately 30 individuals from each of eleven samplinglocations spanning the range of the taxon from Morro Bay, CA, USA to San Quintín, Baja CA, MX. We used double digestion RADseq to prepare libraries for high-throughput sequencing, assemble the dataset in ipyrad producing 5092 SNPs, and analyze population genomics of the species. We place the observed population genomic patterns into the context of regional biogeography, and conclude with recommendations for managing the species.
Wednesday, September 11, 2019
Island rush-rose (Crocanthemum greenei) is a federally threatened shrub that is endemic to the Channel Islands.
Conservation seed collections support species’ survival by acting as an insurance policy in the face of extinction. They can also provide resources for research, restoration and reintroduction. A high-quality conservation seed collection has both depth and breadth – capturing genetic diversity within and geographic diversity among populations. Collecting and storing seeds by maternal line (i.e., seeds from a single individual plant represent one maternal line) provides depth to conservation collections. Previous research has suggested that collecting from 50 maternal lines throughout the geographic extent of a given population increases the odds of capturing the majority of the genetic diversity within that population. Capturing the maximum amount of genetic diversity possible from each population increases the integrity of a conservation collection. Further, keeping maternal lines separate ensures that each line can be equally represented in restoration and reintroduction efforts. Separating seeds by maternal line also creates opportunities for future research, especially when questions center on genetic differences within and between populations. When bulk collections are made, there is only a small chance that each maternal line will be represented when a subsample of the collection is removed for use and valuable information is lost. Although collecting by maternal lines makes seed collection and cleaning more complicated, the amount of information that is retained increases the value of the collection and makes the effort worthwhile.
In the fall of 2017, Dr. Heather Schneider from the Santa Barbara Botanic Garden attended the Kew Millennium Seed Bank Partnership’s three-week Seed Conservation Techniques Training Course. The course brought together conservationists from all over the world to improve conservation seed banking practices used by MSB partners. The course covered a variety of topics from seed biology to field work to processing and storage. At the end of the course, students were encouraged to create an action plan for improving their own seed bank techniques at home. Dr. Schneider will discuss some lessons learned and changes implemented at the Santa Barbara Botanic Garden resulting from this course.