|Abstract|| || |
Burke's goldfields (Lasthenia burkei), Sonoma sunshine (Blennosperma bakeri), and Sebastopol meadowfoam (Limnanthes vinculans) are herbaceous annual plants that inhabit vernal pool and swale habitats mainly on the Santa Rosa Plain of Sonoma County, California. All are Federally- and State-listed as endangered. The goal of our research was to determine the genetic variation between populations in order to inform conservation efforts as to the distinctiveness of populations for seed banking and ex situ conservation, and to infer possible explanations for genetic subdivisions to aid in management decisions. Using 15 microsatellite markers we genetically surveyed 21 populations of L. vinculans, genotyping 577 individuals. Our results indicate a substantial divergence and limited gene flow between Santa Rosa Plain (SRP) populations and an outlying Napa county population (mean FST = 0.180). Among SRP populations genetic variation is significantly lower (FIT = 0.052), with most (82%) of the overall SRP population variation explained by within population genetic variation. L. vinculans shows relatively high genetic diversity at all sites (average Hexp = 0.65 ± 0.19, average Hobs = 0.53 ± 0.23, average number of alleles per locus = 7.419 ± 3.748). We examined 307 L. burkei plants from 15 populations. We used 42 inter-simple-sequence-repeats (ISSR) and random amplified polymorphic DNA (RAPD) nuclear DNA markers to measure genetic characteristics. Species wide, we found that geographically separate populations of L. burkei were genetically distinct (FST = 0.22), using Analysis of Molecular Variance (AMOVA). Half of this variation (FST = 0.11) was due to the difference between Lake and Sonoma County populations; the other half was due to variation within county populations (also FST = 0.11). We were able to examine only 64 individuals of B. bakeri, scattered among five populations, due to unforeseen extraction problems resulting in the poor quality of 80% of our DNA samples. Using 27 ISSR and RAPD markers, our preliminary assessment was that regional and local patterns of genetic variation exist in this species that merit further study in 2008 and are of conservation concern. Our troubleshooting of the extraction protocols has suggested areas where we can improve our methods so as to improve DNA quality in the 2008 survey.