WIREGRASS AND OTHER HERBACEOUS SPECIES’ RESPONSE TO HERBICIDE AND FIRE TREATMENTS by ALLYSON S. READ (Under the Direction of SARA H. SCHWEITZER) ABSTRACT The longleaf pine (Pinus palustris) ecosystem was once dominant within the Atlantic Coastal Plain of the southeastern United States, but it is now reduced to a fraction of its original area. Today, there is a resurgence of interest in the restoration of the longleaf pine-wiregrass (Aristida stricta Michx. and A. beyrichiana Trin. & Rupr.) ecosystem. My objective was to examine the effects of the herbicides, hexazinone (Velpar L) and imazapyr (Chopper), with and without fire, on the regeneration of wiregrass and associated herbaceous plant species typical of the understory of longleaf pine savannas. I hypothesized that treatments would differ in their effect on groundcover vegetation, that the combination of fire and herbicide would better control competition from hardwood species and promote regeneration of wiregrass and associated herbaceous vegetation. Longleaf pine seedling survival and Quercus species frequency of occurrence was greater in hexazinone treatments. Species diversity did not differ among treatments in October 2006. INDEX WORDS: longleaf pine, Pinus palustris, wiregrass, Aristida stricta, A. beyrichiana, hexazinone, imazapyr, sandhill. WIREGRASS AND OTHER HERBACEOUS SPECIES’ RESPONSE TO HERBICIDE AND FIRE TREATMENTS by ALLYSON S. READ B.A., The University of Georgia, 1981 A Thesis Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment of the Requirements for the Degree MASTER OF SCIENCE ATHENS, GEORGIA 2007 © 2007 Allyson S. Read All Rights Reserved WIREGRASS AND OTHER HERBACEOUS SP ECIES’ RESPONSE TO HERBICIDE AND FIRE TREATMENTS by ALLYSON S. READ Major Professor: Sara H. Schweitzer Committee: Karl V. Miller Ronald L. Hendrick Electronic Version Approved: Maureen Grasso Dean of the Graduate School The University of Georgia August 2007 iv ACKNOWLEDGMENTS It has been such a pleasure and reward to work with Dr. Sara Schweitzer on this project. She was always there with a bright smile and great advice. I am grateful to the Georgia Department of Natural Resources, Wildlife Resources Division and the BASF Corporation for funding for this research. This project has been difficult at times, sampling in the hottest place in Georgia in the heat of the summer, but rewarding in the many people I met along the way and all of the wildlife encounters while out in the woods. Nathan Klaus, Haven Barnhill, Alan Isler, and I. B. Parnell and other personnel of the GA DNR, WRD were very helpful with the many questions I had about details and history of Yuchi WMA, and plant species ranking. I am grateful to Don Wardlaw with BASF for outreach support. The East Central Region DNR area managers and supervisor did a wonderful job burning the plots on a dry, windy day in the sandhills. Mike Murphy was invaluable as a research professional helping me with everything from sampling to grants, and organizing all the tedious paper work that needed to be done before we left and when we returned from trips to the field site. I also want to acknowledge the gracious help of the technicians for their positive attitudes and excellent help while assisting in the field: Jason Keenan, Daniel Van Dijk, Jamie Manangan, Mandy McElroy, Lora Loke, Danny Gammon, and Beth Wright of the Warnell School of Forestry and Natural Resources, University of Georgia. My committee members, Karl Miller and Ron Hendrick, were very helpful with advice when things didn’t always go right and in the writing of this paper. And last, but not least, I want to thank my family for supporting me in accomplishing my goal of becoming a wildlife biologist. v TABLE OF CONTENTS Page ACKNOWLEDGMENTS ............................................................................................................. iv LIST OF TABLES........................................................................................................................ vii LIST OF FIGURES ..................................................................................................................... viii CHAPTER 1 Introduction....................................................................................................................1 References .................................................................................................................5 2 Experimental restoration of wiregrass communities......................................................9 Introduction .............................................................................................................10 Study Area...............................................................................................................11 Methods and materials.............................................................................................12 Results .....................................................................................................................14 Discussion ...............................................................................................................17 Acknowledgments ...................................................................................................20 References ...............................................................................................................21 3 Conclusion ...................................................................................................................34 References ...............................................................................................................36 vi APPENDICES ...............................................................................................................................37 A. List of plant species and their ranking as developed with N. A. Klaus, L. Kruse, and M. Moffett of the Georgia Department of Natural Resources, Wildlife Resources Division, estimated seasonally relative to six treatments at Yuchi WMA, Burke County, Georgia, USA. 2 = characteristic of a healthy sandhill community; 1 = can be found on sandhills as well as other areas; 0 = neutral or disturbance prone species that should not be problematic and diminish as soon as climax species take hold; -1 = generally offsite or exotic, may be problematic; -2 = offsite and an indication that fire has been suppressed or other imbalance, may be problematic to recovery of sandhill ecosystem..............................................................................37 B. Total plant species abundance by rank relative to six treatments at Yuchi WMA, Burke County, Georgia, USA, from October 2005 through October 2006.. ...............41 vii LIST OF TABLES Page Table 1: Horizontal cover (Braun-Blanquet cover scale) of woody plant species, bare ground, and forb species measured within 1-m2 square frames at Yuchi WMA, Burke County, Georgia, USA, from October 2005 through October 2006.............................................26 Table 2: Plant height (dm) measured with a Robel pole at Yuchi WMA, Burke County, Georgia, USA, from October 2005 through October 2006............................................................27 Table 3: Vertical cover (%) of vegetation measured within the 0-0.5-m, 0.5-1.0-m, 1.0-1.5-m, and 1.5-2.0-m increments of a 2.5-m vegetation profile board at Yuchi WMA, Burke County, Georgia, USA, from October 2005 through October 2006...............................28 Table 4: Plant species diversity (H’ = Shannon-Wiener index) estimated seasonally relative to six treatments at Yuchi WMA, Burke County, Georgia, USA.............................................30 Table 5: Plant species ranking developed with the Georgia Department of Natural Resources, Wildlife Resources Division, estimated seasonally relative to six treatments at Yuchi WMA, Burke County, Georgia, USA. 2 = characteristic of a healthy sandhill community; 1 = can be found on sandhills as well as other areas; 0 = neutral or disturbance prone species that should not be problematic and diminish as soon as climax species take hold; -1 = generally offsite or exotic, may be problematic; -2 = offsite and an indication that fire has been suppressed or other imbalance, may be problematic to recovery of sandhill ecosystem...............................................................31 Table 6: Plant species evenness estimated seasonally relative to six treatments at Yuchi WMA, Burke County, Georgia, USA.. .......................................................................................32 viii LIST OF FIGURES Page Figure 1: Timeline showing dates of treatment applications and data collection at Yuchi WMA, Burke County, Georgia, USA, October 2005 through October 2006. ..........................33 1 CHAPTER 1 INTRODUCTION AND LITERATURE REVIEW The longleaf pine (Pinus palustris) ecosystem was once dominant within the Atlantic Coastal Plain of the southeastern United States, but it is now reduced to a fraction of its original area. In the early 1900s, longleaf pine was valued for naval stores and timber (Frost 1993). Later, destructive logging, intensive agricultural practices (e.g. cotton farming), and fire exclusion led to further loss of old growth pine forests (Clewell 1989; Noss 1989; Frost 1993; Landers et al. 1995). Today, there is a resurgence of interest in the restoration of the longleaf pine-wiregrass (Aristida stricta Michx. and A. beyrichiana Trin. & Rupr.) ecosystem. Longleaf pine is valued as timber for utility poles, its resistance to pine beetles