ABSTRACT ROSENFELD, KRISTEN MARIE. Ecology of Bird Island, North Carolina: an uninhabited, undeveloped barrier island. (Under the direction of Thomas R. Wentworth.) Barrier islands include some of the most endangered and fragmented ecosystems on the Atlantic coast, providing critical habitat for many species, including some that are threatened and endangered. As the vast majority of these islands have been developed for human usage study and protection of the few remaining undeveloped and undisturbed islands is critical. This study was undertaken in order to characterize the vascular plant communities on Bird Island, an uninhabited, undeveloped barrier island on the border of North and South Carolina, with the objectives of a thorough survey of flora, vegetation, and environment, classification of plant communities, and multivariate analysis of vegetation and environmental data. A floristic inventory of the island and its associated marshes was conducted during the growing season (May- November) of 2002 and 2003. One hundred four 100m2 plots were inventoried for vegetation and environment using protocols developed by the Carolina Vegetation Survey. Plant communities were identified according to the National Vegetation Classification, the Classification of the Natural Communities of North Carolina, and the Carolina Vegetation Survey. Interpretation of vegetation patterns was based on multivariate analysis of vegetation and environmental data. Ninety-one vascular plant species in 35 families, including 4 exotic species, were distributed across 12 communities. Communities on Bird Island appear to be distinctive when compared to those described for other barrier islands in the region. Additionally, the vegetation survey on Bird Island revealed suitable habitat for the federally listed Seabeach amaranth (Amaranthus pumilus); an important dune-building annual of the North American Atlantic coast. Surveys of the late 1980s and early 1990s documented small populations of Seabeach amaranth on Bird Island, but our work found no indication of a population in either 2002 or 2003. Seabeach amaranth’s existence range-wide is threatened by habitat loss and fragmentation, herbivory, and anthropogenic disturbances such as beach driving, hardening, and raking. Published work on this species has been limited, but observations of natural, experimental, and restored populations have indicated relationships between distance from the ocean and both survivorship and reproduction. To quantify this relationship, 314 plants were transplanted at varying distances from the ocean. Plants were monitored monthly from June until December 2003. We found that distance from the ocean had a significant effect on survivorship, size, and reproduction; however, presence of webworms and ghost crabs did not have significant effects on size or reproduction. Distance from the ocean combined with complex factors such as over wash and soil salinity appear to be important indicators of success for both natural and restored populations of this species, and landscape position should be incorporated into future conservation and restoration efforts for A. pumilus in the Carolinas and elsewhere. Overall, we found that the vegetation of Bird Island is mostly intact, with few exotic, invasive species present. Bird Island’s protected status and limited presence of invasive species make it suitable habitat for continued protection and further restoration of rare, threatened, or endangered species, such as Seabeach amaranth. Atlantic barrier islands in general provide distinct community types combined with a small species pool, a combination that may provide a model for examination of larger ecological questions. ECOLOGY OF BIRD ISLAND, NORTH CAROLINA: AN UNINHABITED, UNDEVELOPED BARRIER ISLAND By KRISTEN MARIE ROSENFELD A thesis submitted to the Graduate Faculty of North Carolina State University in partial fulfillment of the requirements for the Degree of Master of Science BOTANY Raleigh, North Carolina 2004 APPROVED BY: Dr. Heather M. Cheshire Dr. Robert K. Peet Dr. John B. Taggart Dr. Qui Yun (Jenny) Xiang Dr. Thomas R. Wentworth Chair of Advisory Committee DEDICATION This is dedicated to my husband, David, and my parents, Bob & June Kostelnik. Their love, patience, participation, and support have allowed me to believe and achieve. ii BIOGRAPHY I grew up in the varied environments of the San Francisco Bay area of California and the foothills of North Carolina. Both these places, while vastly different, shaped my appreciation and love for the outdoors, particularly the coast. This connection to nature manifested itself early on as something that influenced my hobbies and extra curricular interests, but not as a career. The years following my undergraduate experience at Appalachian State University were spent in a rewarding career in business. I enjoyed these years in business and learned a great deal, but I knew that eventually I wanted to pursue further education in a natural sciences field that I was passionate about and one that would “make a difference”. I left my career and spent some time soul searching, taking classes, and discovering a hidden passion for teaching. During this time, I encountered the plant ecology work of Dr. Thomas R. Wentworth, a dedicated teacher. I knew this was the sort of work that would allow me to combine my interests in a meaningful way. My time in the graduate program at North Carolina State University has allowed me to deepen my commitment to a career in ecology, conservation, and education. I plan to complete my Master of Science in Botany in August 2004 and continue at NCSU in pursuit of my Ph.D. iii ACKNOWLEDGMENTS I thank my advisory committee of Drs. Heather Cheshire, Bob Peet, John Taggart, and Jenny Xiang for their guidance and active participation throughout the course of my study. I particularly thank the chair of my committee, Dr. Tom Wentworth. He has been a role model, inspiration, teacher, mentor, cheerleader, and friend without whom this work would not have been possible. I also thank Dr. Gerald Van Dyke whose confidence in my ability to get accepted and to succeed in graduate school inspired my application in the first place. Lastly, I thank Ellen Damschen and Dale Suiter for their professional advice and more importantly, their personal friendship. I cannot imagine having made it down this road without them. iv TABLE OF CONTENTS Page LIST OF TABLES................................................................................................ vii LIST OF FIGURES ............................................................................................. viii PREFACE................................................................................................................1 VASCULAR PLANT COMMUNITIES OF A CAROLINA BARRIER ISLAND...........................................................................3 Abstract........................................................................................................3 Introduction..................................................................................................4 Methods........................................................................................................6 Study Site.........................................................................................6 Sampling Methods...........................................................................7 Data Analysis...................................................................................9 Results and Discussion..............................................................................11 Flora ...............................................................................................11 Comparative Community Classification and Description .............13 Diversity.........................................................................................21 Environmental Interpretation.........................................................22 Conclusions................................................................................................23 Species List................................................................................................25 Acknowledgments......................................................................................29 References..................................................................................................30 THE EFFECT OF DISTANCE FROM THE OCEAN ON SURVIVORSHIP, SIZE, AND REPRODUCTION OF THE THREATENED BEACH PLANT, SEABEACH AMARANTH (AMARANTHUS PUMILUS RAFINESQUE)...............................44 Abstract......................................................................................................44 Introduction................................................................................................44 Methods......................................................................................................48 Study Species.................................................................................48 Study Site.......................................................................................49 Planting and Monitoring................................................................50 Data Analysis.................................................................................51 Results ........................................................................................................53 Survivorship...................................................................................53 Plant Size.......................................................................................53