University of Central Florida STARS Retrospective Theses and Dissertations 1998 Composition and change of maritime hammock flora in east- central Florida after 20 years Donald John Spence University of Central Florida, [email protected] Part of the Biology Commons, and the Botany Commons Find similar works at: https://stars.library.ucf.edu/rtd University of Central Florida Libraries http://library.ucf.edu This Masters Thesis (Open Access) is brought to you for free and open access by STARS. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of STARS. For more information, please contact [email protected]. STARS Citation Spence, Donald John, "Composition and change of maritime hammock flora in east-central Florida after 20 years" (1998). Retrospective Theses and Dissertations. 2543. https://stars.library.ucf.edu/rtd/2543 Composition and Change of Maritime Hammock Flora in East-Central Florida After 20 Years By Donald John Spence B.S. Stetson University, 1994 THESIS Submitted in partial fulfillment of the requirements for the Master of Science degree in Biology in the graduate studies program of the College of Arts and Sciences University of Central Florida Orlando, Florida Summer Term 1998 ABSTRACT The vegetation of eight east-central Florida maritime hammocks studied in 1997 were compared to similar data collected over 20 years ago. Study sites are located in the northern half of the Indian River Lagoon system mostly within Canaveral National Seashore and Merritt Island National Wildlife Refuge. The upland hammock vegetation throughout the state generally has an oak-palm association, but here these species dominate. Results show that sabal palm, live oak, laurel oak, and pignut hickory, the four dominant tree species in 1976-77, are still dominant in 1997; however, there has been a loss in tree species richness. Most shrub species found during both studies increased in dominance over the 20 years and there was almost a complete turnover in the composition of herbs. Variability in winter freeze events has caused a unique mixture of plant species to occur here. Many of the maritime hammock's tropical plants are in the northern limit of their range, giving these hammocks a unique ecotonal character. Tropical invasive exotics have increased in frequency, density, and basal area and pose a threat to this diverse floral complex. My education would not have been possible with out the love and support of my parents, Don and Peg. This Thesis is dedicated to them. Thank you! Think Globally - Act Locally "Nothing in the world can take the place of persistence. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent." -Calvin Coolidge iii ACKNOWLEDGMENTS I thank the following people for taking time out of their day(s) to assist me with sampling, data collection, and data analysis: Eric Roth, Amoi Dort, Jason Godin, Tamara Mayer, Pat Daren, Michelle Godard, Ludi Lelis, and John Weishampel. Additional appreciation is given to Dr. Linda Walters for use of the Feller's House Field Station, to Dr. Henry 0. Whittier for access to the UCF Herbarium, Dr. Brooks Madsen in the Chemistry Department, the Biology Department for their partial funding, and to Dr. Jack Stout for the use of his data. Every site I visited was under the management of a public agency. I thank the following people and agencies for their support and assistance. John Stiner, Canaveral National Seashore; Marc Epstein, Merritt Island National Wildlife Refuge; Anne Birch, Brevard County, Office of Natural Resources Management; and Paul Schmalzer, Dynamac Corporation. And finally, but not lastly, I thank members of my committee: Dr. Walter K. Taylor, Dr. John F. Weishampel, and Dr. I. Jack Stout for their advice, support, and encouragement. iv TABLE OF CONTENTS LIST OF TABLES .................................................................... vii LIST OF FIGURES .................................................................. viii INTRODUCTION .................................................................... 1 Hammock Characterization ................................................. 4 Fire ............................................................................. 8 Soil ............................................................................. 9 Climate ........................................................................ 10 Study Objectives .............................................................. 13 METHODS Study Sites .................................................................... 14 Sampling Techniques Vegetation ............................................................ 18 Soils ................................................................... 22 Ordination ..................................................................... 24 RESULTS Regional Vegetative Dynamics ............................................. 25 Strata Comparisons Trees ........................................ ·.......................... 28 Shrubs ................................................................. 32 Herbs ................................................................... 35 Within Hammock Dynamics Trees .................................................................. 38 Shrubs ................................................................. 38 Herbs .................................................................. 45 Soil .................................................................... 45 Additional Community Components Temperate and Tropical Species .................................. 52 V Exotic Species ....................... .. ......................... .. ... 53 Comparison of Dynamics ................ ...................... ... .......... 54 DISCUSSION ......................................................................... 58 Statewide Comparisons ....... ................. ........ .... .... .............. 61 Succession .. ............. ......... ............ ......................... ... ..... 64 Exotic Species ................................................................ 68 Seed Dispersal. ............................................................... 68 CONCLUSIONS ..................................................................... 71 APPENDICES A. Species List for 1976-77 ................................................ 74 B. Species List for 1997 ........................... ......................... 77 C. Importance Values for 1976-77 ........ ... ................ ............ 80 D. Importance Values for 1997 ............................................ 82 LITERATURE CITED .............................................................. 84 vi LIST OF TABLES 1 Hammock characteristics ......... ......... .................... .................... .............. 16 2 Topographic and surrounding characteristics of hammocks .............................. 17 3 Twelve highest ranking importance values for trees ..................... .. ................ 3 0 4 Twelve highest ranking importance values for shrubs .. ................................. 3 3 5 Twelve highest ranking importance values for herbs ...................................... 3 6 6 Soil characteristics for all sites .............................. ................................. 49 7 Correlations of soil properties .... ............................................................. 50 8 Tropical and temperate species comparisons ................................................ 53 9 Hammock change in comparison to distance to ocean .................................... 57 vii LIST OF FIGURES 1 Location and types of ecotones.. 12 2 Location of the eight study sites in east-central Florida .................................... 15 3 PCQ sampling design ............................................................................ 20 4 Averaged diversity and evenness of trees for all hammocks .............................. 26 5 Averaged diversity and evenness of shrubs for all hammocks ............................ 27 6 Averaged diversity and evenness of herbs for all hammocks .............................. 29 7 Ordination of hammocks based on tree composition ........................................ 31 8 Ordination of hammocks based on shrub composition .. ................................... 34 9 Ordination of hammocks based on herb composition ..................................... 3 7 10 Comparison of tree species diversity ......................................................... 3 9 11 Comparison of tree species evenness ........................................................ .40 12 Comparison of tree species richness ......................................................... .41 13 Comparison of shrub species diversity ....................................................... 42 14 Comparison of shrub species evenness ...................................................... .43 15 Comparison of shrub species richness ....................................................... .44 16 Comparison of herbs species diversity ........................................................ 46 17 Comparison of herb species evenness ........................................................ .4 7 18 Comparison of herb species richness ......................................................... .48 19 Ordination of hammocks based on soil properties ........................................