Location: Southern Horticultural ResearchTitle: Genetic diversity of flowering dogwood in the Great Smokey Mountains National Park) Author
Submitted to: Tree Genetics and Genomes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2011
Publication Date: 2/12/2012
Citation: Hadziabdic, D., Wang, X., Wadl, P., Rinehart, T.A., Ownley, B., Trigiano, R. 2012. Genetic diversity of flowering dogwood in the Great Smokey Mountains National Park. Tree Genetics and Genomes. 8(4):855-871. DOI 10.1007/s11295-012-0471-1. Interpretive Summary: Both widespread and localized landscape disturbances due to anthropogenic expansion, invasion of non-native species or severe disease outbreaks present an opportunity to understand effects of these disturbances on genetic structure and variability within and among populations. In this study, we used microsatellite loci to evaluate genetic differentiation and population structure of flowering dogwoods in the Great Smokey Mountains National Park. By assessing genetic diversity and population dynamics of this native tree, we aimed to answer how much genetic variation exists within and among remaining populations of flowering dogwood and whether these populations are genetically structured. Our goal is to have better understanding of the current status of flowering dogwood populations in the Great Smokey Mountains National Park to assist in making effective conservation decisions.
Technical Abstract: In the past three decades, flowering dogwood (Cornus florida) populations have experienced severe declines caused by dogwood anthracnose. Mortality has ranged from 48 to 98%, raising the concern that the genetic diversity of this native tree has been reduced significantly. In this study we investigated levels of genetic diversity and population structure of flowering dogwood populations in the Great Smoky Mountains National Park (GSMNP). Understanding the factors influencing geographic distribution of genetic variation is one of the major concerns for preserving biodiversity and conservation of native populations. Eighteen microsatellite loci were used to evaluate the level and distribution of genetic variation of native flowering dogwood trees throughout the GSMNP. Significant genetic structure exists at both landscape and local levels. Two genetic clusters exist within the park separated by the main dividing ridges of the Great Smoky Mountains. The differentiation of the clusters is subtle, but statistically significant, with gene flow evident through low-elevation corridors indicating nonrandom mating that occurs between related individuals despite wide dispersal of seeds. Although high mortality rate and reduced fecundity caused by dogwood anthracnose severely affected native flowering dogwood populations throughout the entire GSMNP, this study confirmed that considerable genetic diversity of flowering dogwood still exists at the population level. It seems unlikely that recent demographic dynamics have resulted in a depletion of genetic variation.