Abstract Detail

Population Genetics

Mohn, Rebekah [1], Yatskievych, George A. [2], Swift, Joel [3], Edwards, Christy [4].

A population genetic analysis to test the causes of a disjunction between the Ozarks and Appalachians in tall larkspur (Delphinium exaltatum).

Delphinium exaltatum, a perennial herb that has insect pollenated flowers and gravity and water dispersed seeds, is globally considered vulnerable (G3) and is most threatened by encroachment of woody species due to fire suppression. Its distribution exhibits an over 650 km disjunction between the Ozarks in southern Missouri and the Appalachians, and the biogeographical forces that have been hypothesized to have caused this disjunction include isolation by vicariance by high waters during interglacial times in the Pleistocene, recolonization into similar habitats from a Pleisocene refugium in the coastal plain, or more recent long-distance dispersal. In this study, we investigated levels of genetic diversity and patterns of genetic structure in D. exaltatum with the goal of understanding the biogeographical forces that have caused this disjunction between the Appalachians and Ozarks. Twelve populations (five from the Missouri Ozarks and seven from the Appalachians and Eastern United States) totaling 253 samples were analyzed at ten microsatellite loci. Bayesian analyses of genetic structure split the populations into the following four clusters: 1) one containing all the Ozark populations and populations in eastern Tennessee, 2) one containing the central Appalachian populations in North Carolina, West Virginia, Virginia, and Pennsylvania, 3) one containing the only population east of the Appalachians in North Carolina, and 4) one containing one population from Ohio. Genetic analyses did not support the hypothesis that the disjunction between the Ozarks and Appalachians was the result of a vicariance. The patterns of genetic structure in D. exaltatum indicate that the species likely occupied at least two refugia during the Pleistocene and that the species has subsequently expanded its range. The disjunction occurred relatively recently, and was likely caused either by recent extirpations in some part of its range or by long-distance dispersal that allowed migration between populations in the Ozarks and Tennessee.

1 - Miami University, Department of Biology, Oxford, Ohio, 45056, USA
2 - University of Texas at Austin, Plant Resources Center, 110 Inner Campus Dr., Stop F0404, Austin, TX, 78712-1711, USA
3 - Missouri Botanical Garden, Center for Conservation and Sustainable Development, PO Box 299, St. Louis, MO, 63166, USA
4 - Missouri Botanical Garden, P.O. Box 299, St. Louis, MO, 63166, United States

Keywords:
Delphinium
Tall larkspur
Plant disjunctions
microsatellites
Ozarks.

Presentation Type: Poster
Session: P, Population Genetics Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PPG007
Abstract ID:495
Candidate for Awards:None