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Clemson University TigerPrints All Dissertations Dissertations 5-2011 AN ECOLOGICAL, GENETIC, AND REPRODUCTIVE STUDY OF BIG BLUESTEM (ANDROPOGON GERARDII) POPULATIONS IN THE CAROLINAS Robert Tompkins Clemson University, [email protected] Follow this and additional works at: https://tigerprints.clemson.edu/all_dissertations Part of the Plant Sciences Commons Recommended Citation Tompkins, Robert, "AN ECOLOGICAL, GENETIC, AND REPRODUCTIVE STUDY OF BIG BLUESTEM (ANDROPOGON GERARDII) POPULATIONS IN THE CAROLINAS" (2011). All Dissertations. 724. https://tigerprints.clemson.edu/all_dissertations/724 This Dissertation is brought to you for free and open access by the Dissertations at TigerPrints. It has been accepted for inclusion in All Dissertations by an authorized administrator of TigerPrints. For more information, please contact [email protected]. AN ECOLOGICAL, GENETIC, AND REPRODUCTIVE STUDY OF BIG BLUESTEM (ANDROPOGON GERARDII) POPULATIONS IN THE CAROLINAS ________________________________________________________________________ A Dissertation Presented to The Graduate School of Clemson University ____________________________________________________ In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Plant and Environmental Science ____________________________________________________ by Robert David Tompkins May 2011 ________________________________________________________________________ Accepted by Dr. William Stringer, Committee Chair Dr. Halina Knap Dr. Saara DeWalt Dr. Elena Mikhailova ABSTRACT AN ECOLOGICAL, GENETIC, AND REPRODUCTIVE STUDY OF BIG BLUESTEM (ANDROPOGON GERARDII) POPULATIONS IN THE CAROLINAS Andropogon gerardii (Big Bluestem) is a dominant grass of the North American tallgrass prairie and is also found in remnant populations in the eastern U.S., including North and South Carolina. This research included a systematic study of the ecology, genetics, and reproductive potential within and among A. gerardii populations in the Carolinas. Floristic composition and edaphic (soil) features were characterized for eight A. gerardii populations across various physiographic regions of North and South Carolina. A total of 362 quadrats (1 m x 1 m) were sampled during the 2006-2008 growing seasons. A total of 306 vascular plant species was identified comprising 64 families, including 99 (32%) graminoids. Andropogon gerardii had the highest Commonness Index (CI) value (5900), followed by Rubus spp. (1260). Community Coefficient (CC) values were <0.5 for all pairings between sites, indicating high dissimilarity in species composition among sites. Soil pH values varied among the sites from 4.8 to 6.9. Calcium and Mg nutrient values were also highly variable. An out- crossing reciprocity study was conducted with five A. gerardii populations. Fifteen treatments were established at four garden sites. Seed germination was low for both out- crossed (4.8%) and selfed (2.4%) pairings. However, germination was significantly higher for both out-crossed and selfed seeds from ramets from the Suther Prairie population. There were no significant differences in seed set among plants from the five populations. Protein electrophoresis was used to assess genetic variation within and among nine local A. gerardii populations from various physiographic regions of both ii North and South Carolina. Twenty-seven polymorphic loci and one monomorphic locus were resolved. Populations contained high levels of genotypic diversity. Genetic diversity was high at both the pooled species-wide level and at the mean within-population level. For the species-wide sample, percent polymorphic loci (Ps) was 96.7%, the number of alleles per polymorphic locus (APsp) was = 4.07, the mean number of alleles per locus (As) was = 3.97, and the genetic diversity (Hes) was 0.422. For within- populations, the mean Pp = 81.2%, APp, = 2.63, Ap = 2.38, and Hep = 0.340. Levels of within population (Hep) genetic diversity ranged from 0.181 for the Sumter National Forest I population to 0.462 for the Bowman Barrier population. Genetic structure among populations (Gst) was 0.175, indicating that 83% of the genetic variation is found within-populations. The level of genetic diversity for the three larger populations (He = 0.387) and for the six smaller populations (He = 0.330) was not significantly different (p = 0.5535). Nei‟s unbiased genetic identity between pairs of populations ranged from 0.6386 (populations BlackJacks Heritage Preserve and Sumter National Forest I) to 0.9692 (populations Buck Creek Serpentine Barrens and Suther Prairie). Of the population sites, the Blackjacks Heritage Preserve population had the lowest measure of genetic identity with the other population sites, while the Suther Prairie population had the highest. The Mantel test showed no significant genetic isolation by geographic distance (r = 0.065; p =0.614). Allelic richness values were high for the populations. Banding patterns were consistent with disomic inheritance. However for two loci (PGI3; UGPP1), tetrasomic patterns were indicated. iii ACKNOWLEDGEMENTS There are many individuals and agencies to thank for their contributions to making this research project possible. First of all I would like to acknowledge the following landowners and agencies for allowing me access to do research on their properties; the Suther family, Rick Harris, George Bowman, the South Carolina Department of Natural Resources, and the U.S. Forest Service. Grant support for the research was made possible by the U.S. Forest Service and Dr. Elena Mikhailova. I will always be indebted as well to individuals who provided technical support for different aspects of the research; Dr. William Bridges, Jr. for help with the statistical analysis, Dr. Patrick McMillan for help with the identification of difficult taxa, Dr. Jim Hamrick and Dr. Dorset Trapnell of the University of Georgia for help with both the analysis and comments on the isozyme study; and Keith Richardson for help in the field and traveling with me to numerous sites. In addition, I want to thank the members of my committee, Dr. Saara DeWalt, Dr. Halina Knap, and Dr. Elena Mikhailova for their support throughout this project. I would like to especially thank my advisor, Dr. William Stringer, who helped me throughout this project with many different aspects of the research and analysis, for which I will be forever grateful. Lastly, I would like to thank my family for their patience and sacrifice over the five plus years of my program in completing this study. iv TABLE OF CONTENTS Page TITLE PAGE .................................................................................................................... i ABSTRACT ..................................................................................................................... ii ACKNOWLEDGEMENTS ............................................................................................ iv TABLE OF CONTENTS ................................................................................................. v LIST OF TABLES ......................................................................................................... vii LIST OF FIGURES ........................................................................................................ ix INTRODUCTION ........................................................................................................... 1 CHAPTER 1 - BIG BLUESTEM (ANDROPOGON GERARDII VITMAN) COMMUNITIES IN THE CAROLINAS: COMPOSITION AND ECOLOGICAL FACTORS ............................................................................................. 7 Abstract .................................................................................................................. 8 Introduction ............................................................................................................ 9 Study Sites ........................................................................................................... 10 Materials and Methods ......................................................................................... 15 Results .................................................................................................................. 16 Discussion ............................................................................................................ 25 Literature Cited .................................................................................................... 30 Appendix ............................................................................................................. 35 CHAPTER 2 - AN OUT-CROSSING RECIPROCITY STUDY BETWEEN REMNANT BIG BLUESTEM (ANDROPOGON GERARDII VITMAN) POPULATIONS IN THE CAROLINAS ...................................................................... 53 Abstract ................................................................................................................ 54 Introduction .......................................................................................................... 55 Materials and Methods ......................................................................................... 57 Results .................................................................................................................. 62 Discussion ............................................................................................................ 70 Literature Cited ...................................................................................................