rare plant

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.

Date Recorded: 
Wednesday, September 11, 2019

Daniella DeRose, Chicago Botanic Garden

Chicago Botanic Garden’s Plants of Concern (POC) program is a collaboration between citizen scientists, natural resource managers, and researchers to collect data on rare plant populations in northeastern Illinois. The primary goal is to identify best conservation practices, while creating awareness and providing education on why conservation matters. POC engages citizen scientists, collects census data on rare plant populations—including identifying invasive species, threats, and evidence of management—and provides data to land managers. Data generated by POC inform the Illinois rare species listing process and are used by land managers to understand population trends and prioritize activities. Program monitors also serve as ecological site stewards. POC has monitored 292 species and 2453 populations, trained 953 volunteers, and worked with 135 landowners as of December 2018. POC trains its citizen scientists to collect standardized data. Partners include volunteer groups, government agencies, private landowners, and researchers.

POC is learning how management impacts rare species. Hill’s thistle, Cirsium hillii, is a habitat specialist threatened by habitat loss and lack of management. Although monitoring and management data suggested that burning and brush removal increase population size, in-depth study revealed a discrepancy between census size and effective population size. POC founder Susanne Masi led level 2 monitoring efforts looking at demography of C. hillii. CBG scientist Jeremie Fant & MS students Abigail White and Nora Gavin-Smyth found that most populations are highly clonal. Self-incompatibility, low flowering rates, and lack of compatible mates lead to low/no seed set, but genetic augmentation (introduced pollen) is able to reduce mate limitation. Based on these results, POC modified its monitoring protocol for C. hillii, introducing a minimum size for identifying individuals. CBG scientist Jacob Zeldin developed new micropropagation techniques that allow for the rapid and controlled cloning of individual C. hillii genotypes year-round with minimal space and materials. Land managers are now interested in using genetic augmentation for this species, sharing genetic material between sites.

Date Recorded: 
Thursday, May 2, 2019