UN1VEF.SITY OF HAWAl'1 LIBRARY POPULATION STRUCTURE OF THE HAWAIIAN TREE FERN CIBOTIUM CHAMISSOI ACROSS INTACT AND DEGRADED FORESTS 0' AHU, HAWAI'I A THESIS SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI'I IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS IN GEOGRAPHY (ECOLOGY, EVOLUTION AND CONSERVATION BIOLOGY) DECEMBER 2007 By Naomi N. Arcand Thesis Committee: Lyndon Wester, Chairperson Stacy Jorgensen Tamara Ticktin We certify that we have read this thesis and that, in our opinion, it is satisfactory in scope and quality as a thesis for the degree of Master of Arts in Geography. HAWN CB5 .H3 no. ~yy 3 THESIS COMMITTEE ii ACKNOWLEDGEMENTS I would like to thank the American Association of University Women for funding this research project and the Army Natural Resources staff for their invaluable hours of staff time, site access, and field support. I would like to express much gratitude to my advisor, Lyndon Wester for his advice, support, and patience throughout my graduate program at University of Hawai'i-Miinoa. I also have much gratitude to Tamara Ticktin and Stacy Jorgensen for their guidance in thesis design, data analysis, and revisions. Thanks to the Ecology, Evolution, and Conservation Biology Program for loaning research equipment. I would like to acknowledge Kay Lynch, the hapu 'u horticulturalist extraordinaire, for her time and efforts to grow Cibotium, and also for her feedback and endless positive support for native fern research and awareness in Hawai'i. I thank the following staff and management agencies for supporting and facilitating access to research sites: Talbert Takahama, Reuben Mateo, Betsy Gagne, and the Hawai'i Natural Area Reserve Commission; Martha Yent and Kahana State Park; Ray Baker, Nellie Sugii, Alvin Yoshinaga, and Lyon Arboretum; Earl Pawn and the Department of Forestry and Wildlife Honolulu Watershed Forest Reserve; Joel Lau and Roy Kam at Hawai'i Natural Heritage Program; and Clyde Imada at the Bishop Museum. I could not have completed my project without the help of numerous field assistants, including Jane Beachy, Aaron Shiels, Tom Ranker, Kay Lynch, Lara Reynolds, John Delay, Aurora Kagawa, Maggie Sporck, JeffMikulina, Kapua Kawelo, Joby Rohrer, Steph Joe, Leann Obra, Dominic Souza, Will Weaver, Vince Costello, Julia Gustine, Where's George?, Susan Ching, Dan Sailer, and Charlotte Yamane. I also thank the following people for their assistance and III invaluable input: Jane Beachy, Dieter Mueller-Dombois, LawTen Sack, Matt McGranaghan, Ev Wingert, Dave Olsen, Tom Giambelluca, Ross Sutherland, Scott Lynch, Colleen Moore, Susan Beatty, Dan Palmer, Travis Idol, Dave Palumbo, Matt Keir, Matt Burt, Steve Mosher, Seth Cato, Krista Winger, Lasha Salbosa, Daniel Toibero, Bob Kinzie, Frank Howarth, Lloyd Loope, Mach Fukada, Pat Conant, Mark Wright, Peter Follett, Paul Banko, Jan TenBruggencate, Jeff Mikulina, and Nathan Yuen. Finally, thanks to my parents Renee and Dennis Arcand for their continuous support and encouragement to complete this project. IV TABLE OF CONTENTS Acknowledgements ....................................................... iii List of Tables ............................................................. v iii List of Figures ............................................................ ix Chapter I: Introduction. .. 10 Problem ......................................................... 12 Purpose .......................................................... 15 Background ...................................................... 16 Ecological Role of Tree Ferns ........................... 16 The Genus Cibotium . .. 19 Framing Research in Restoration ......................... 24 Disciplinary Framework .......................................... 27 Significance ..................................................... 28 Research Questions .............................................. 29 Chapter 2: Methods ....................................................... 31 Locating Study Sites ............................................. 31 Individual Site Descriptions . .. 34 Kahanahiiiki and Pahole . .. 34 Three Points ............................................ 37 'Ohikilolo . .. 38 Kahuku ................................................. 39 Kahana ................................................. 41 'Aiea Ridge ............................................. 42 v Lyon Arboretum ........................................ 43 Plot Measurements ............................................... 44 Cibotium Distribution and Habitat ................................ 47 Outplanting Trial.. ................... , ........................... 47 Statistical Analyses .............................................. 49 Chapter 3: Results ......................................................... 52 Population Structure and Morphological Variation ................. 52 All Measured C. chamissoi .............................. 52 Paired FencedlUnfenced Plots ........................... 53 All Unfenced Plots ...................................... 62 C. chamissoi Environmental Recruitment Correlations ............. 64 All Measured C. chamissoi . .. 64 All Unfenced Plots. .. 68 Variance in C. chamissoi Recruitment and Abundance ............. 72 Presence of Epiphytes ............................................ 77 Cibotium Distribution Observations and Habitat Parameters ........ 79 Outplanting Trial. ................................................ 81 Chapter 4: Discussion ..................................................... 82 Effects of Ungulate Predation ..................................... 82 Effects of Weed Control.. ........................................ 84 Effects of Environmental Conditions. .. .. 85 Morphological Variation ......................................... 90 Epiphytes. .. .. .. 92 VI Cibotium Distribution. .. 93 Outplanting Trial. .. 94 Future Research .................................................. 95 Conservation Implications ........................................ 97 Appendix I: Field Data Sheets ............................................. 99 Appendix II: Outplanting Trial: Individual C. chamissoi Data ............... 103 Appendix Ill: Results of Soil Analyses: Paired Plots ........................ 104 Appendix IV: Results of Soil Analyses: All Unfenced Plots ................. 105 References. .. 106 VII LIST OF TABLES 1. Measured Cibotium growth rates ....................................... 22 2. Summary description of research plots ................................. 34 3. All plots: average size class morphology .................. , ....... ." .... 53 4. ANOV A results: fenced/unfenced immature C. chamissoi relative abundance ...................................... 56 5. ANOVA results: weed control and morphological variation ............. 58 6. Two-way ANOV A results: fencing/weed control and trunk length ....... 59 7. Mean differences in morphology: fenced and unfenced plots ............ 61 8. Correlates: All Unfenced C. chamissoi . ................................ 69 9. Correlates: All Unfenced Plots ......................................... 71 10. Principal components analysis total variance ........................... 73 II. Varimax rotation of three factor solution for variance: pattern/structure for coefficients. .. 75 12. Pearson correlates: multiple regression model variables ................ 76 13. Multiple regression results ............................... ' ............ 76 14. MUltiple regression model predictor variables .......................... 77 V111 LIST OF FIGURES Figure Page 1. Location of research plots: O'ahu, Hawai'i ............................ 33 2. Kahanahaiki and Pahole plot locations ................................. 35 3. Three Points plot locations ............................................ 37 4. 'Ohikilolo plot locations .............................................. 39 5. Kahuku plot location ................................................. 40 6.. Kahana plot location .................................................. 41 7. 'Aiea Ridge plot location ............................................. 43 8. Lyon Arboretum plot location ......................................... 44 9. Population structure and abundance: fenced and unfenced .............. 54 10. Population structure by percentage: fenced and unfenced ............... 55 II. Average population structure and abundance: fenced and unfenced ................................................. 56 12. Two-way ANOVA: mean trunk length by fencing and weeding ........ 59 13. Population structure and abundance: all unfenced ...................... 63 14. Population structure by percentage: all unfenced. .. 64 15. Correlation between trunk length and rainfall: all C. chamissoi ..................................................... 65 16. Correlation between understory cover (excluding C. chamissot) and size class ............................... 67 17. Correlation between invasive understory cover and trunk length ........ 68 IX LIST OF FIGURES (CONTINUED) Figure 18. Principal components analysis screeplot .............................. 74 19. Correlation between presence of epiphytes and basal trunk circumference. .. 78 20. Correlation between presence of epiphytes and trunk length ............ 79 21. Observations of Cibotium on O'ahu ................................... 80 x CHAPTER 1. LNTRODUCTION The fern forest has an inimitable charm and a distinctive beauty. In architecture and atmosphere, it is unique ... Her radiantfern groves will long remain among Hawaii's noblest