Genetic variation and its relationship to population size in reintroduced populations of pink sand verbena, Abronia umbellata subsp breviflora (Nyctaginaceae)

Genetic monitoring of reintroduced plant populations can allow assessment of the success in establishing new populations that genetically resemble native populations. We used a PCR-based method (Intersimple Sequence Repeats) to quantify genetic variation in four reintroduced populations of Abronia umbellata ssp. breviflora, an annual forb native to the Pacific Coast that is state-listed endangered in Oregon. The reintroduced populations ranged in size from 18 to 4, 111 individuals in the year they were sampled. Genetic variation was also quantified in the natural population that served as the seed source for the reintroduction efforts. A total of 77 loci (bands) was observed using two ISSR primers, providing 65 polymorphic loci. A significant, positive regression was observed between the log of population size for the five populations and genetic variation when measured as percent polymorphic loci (P), expected heterozygosity (H-e), and with a dissimilarity index (1 - S-xy) based on band sharing. Two of the reintroduced populations maintained approximately 90% of the genetic variation we observed in the source population. Based on these results, we predict that reintroduced populations of A. u. ssp. breviflora that have at least 1, 000 individuals should maintain 90% of the genetic variation of the source population.