Population Genetics of Neviusia cliftonii (Shasta Snow-Wreath): Patterns of Diversity in a Rare Endemic

• Published in: Western North American naturalist Vol. 72; no. 4; pp. 457 - 472
• Main Authors: DeWoody, Jennifer, Lindstrand, Len, Hipkins, Valerie D., Nelson, Julie Kierstead
• Format: Journal Article
• Language: English
• Published: Provo Brigham Young University 01-12-2012; Western North American Naturalist
• Subjects: Alleles; asexual reproduction; Biological diversity; Botanical research; Classification; Ecological genetics; Flowers & plants; gene frequency; Genetic aspects; Genetic diversity; Genetic loci; Genetic research; Genetic variation; genotype; isozymes; lakes; loci; multivariate analysis; Neviusia; Plant populations; Plants; Population biology; Population ecology; Population genetics; Population size; Rosaceae; shrubs; Studies; variance; Watersheds; California; United States; Shasta County California
• ISSN: 1527-0904; 1944-8341
• DOI: 10.3398/064.072.0405

Neviusia cliftonii (Rosaceae), the Shasta snow-wreath, is an endemic shrub found in the vicinity of Shasta Lake, Shasta County, California. First described 20 years ago, the species is of conservation concern due to its restricted range, a low number of known populations, and the potential impacts on or threats to many of these populations. To assess the genetic structure of N. cliftonii, 21 of the 23 known populations were sampled for isozyme analysis. Genetic and multivariate analyses were used to assess levels of genet (genotypic) diversity, allelic variation, and population differentiation. When assessed at 17 loci, a total of 48 multilocus genotypes were identified in the collection of 410 samples, indicating N. cliftonii is capable of significant vegetative reproduction. Five populations were composed of a single genet each, with an average of 3.14 genets per population and a maximum of 15 genets in a single population, Allelic diversity was low, with a maximum of 3 alleles observed at one locus. Populations were differentiated, with 85% of the allele frequency variance distributed among populations. Multivariate analysis identified 3 clusters of genetically similar populations: one cluster composed of 15 populations, a second cluster composed of 5 populations, and one population being distinct. Individuals from the distinct population displayed unique alleles at 2 loci (AAT-1 and AAT-2). The distribution of populations among clusters did not correspond to geographic (watershed) or substrate classifications, indicating that additional, unmeasured factors may influence the genetic structure of this species.