AN ECOLOGICAL STUDY OF THE FLORIDA ROYAL PALM, ROYSTONEA ELATA (BARTRAM) F. HARPER by Julie L. Jones A Thesis Submitted to the Faculty of the College of Science in Partial Fulfillment of the Requirements for the Degree of Master of Science Florida Atlantic University Boca Raton, Florida April 1983 AN ECOLOGICAL STUDY OF THE FLORIDA ROYAL PALM, ROYSTONEA ELATA (BARTRAM) F. HARPER by Julie L. Jone s This thesis was prepared under the direction of the candidate's thesis advisor, Dr. Daniel F. Austin, Department of Biology. It was submitted to the faculty of the College of Science and was accepted in partial fulfillment of the requirements for the degree of Master of Science. SUPERVISORY COMMITTEE: bThesis. &.J~ Advisor ' ced Studies ii ACKNOWLEDGEMENTS I would like to thank Dr. Daniel Austin, my major professor, f or giving me help and encouragement throughout this project. I am grate­ ful to Dr. Manley Boss and Dr. Thomas Sturrock for their advice and assistance. Geri Jones deserves a special thanks for the stressful, last minute typing job that completed this thesis. The field work was done with the help of Dan Austin and his wife Sandy, Clif Nauman, and Brad Bennet. The assistance that Brad lent in the field was exceptional and very much appreciated. I would like to thank my mother who has always encouraged me and Jess Howard who kept after me to finish. The preliminary work for this project was funded by the Department of the Interior's Office of Endangered Species, under Contract Number 14-16-004-78-105. The hydrological work in the Fakahatchee Strand was funded by the Department of Natural Resources. Special thanks goes to Captain K. C. Alvarez of the Department of Natural Resources for helping me obtain funding and for giving me unlimited access to the Fakahatchee Strand State Preserve and its personnel. iii ABSTRACT Author: Julie L. Jones Title: An Ecological Study of the Florida Royal Palm, Roystonea elata (Bartram) F. Harper Institution: Florida Atlantic University Degree: Master of Science Year: 1983 The object of this study was to determine habitat preference (seedlings) and adults) and the population status of the Florida Royal Palm (Roystonea elata (Bartram) F. Harper], in the Fakahatchee Strand State Preserve. Associated species, seedling establishment and germination, growth rates, size class ratios and elevation of establishment (epiphytic nature) were examined. The palm showed a preference for high ground as indicated by the increasing colonization of elevated logging tramways. Seeds germinated under low light conditions in 17-22 days. Seedlings had an escalating growth rate from 4.2 em/year for seedlings to approximately 50 em/year for adults. Each size class was well repre- sented in the Fakahatchee Strand, suggesting that reproduction was not being hindered by changes in water level, cold and area urbanization. Elevation of seedling establishment was a function of water level during that particular year and did not correlate year to yea~. These data indicate a stabilization of the Royal Palm population in the Fakahatchee Strand. iv TABLE OF CONTENTS Page ABSTRACT • . • • • • . • • • • . • • • • • . • • . • • . • • • • • • • . • • • • . • • • • • • • • • • • • . i v LIST OF TABLES • . • • • • . • • • • • • . • . • • • . • • . • • • . • • • • • . • • • • • • • • • . vi LIST OF FIGURES • • • • • . • • • • • . • • • • • • • . • • • • • • • • . • • • • • • • • • • • • • • • vii INTRODUCTION • . • • • • • • • . • . • . • • . • • • . • • . • • . • • . • • • • . • • • • • • • • • 1 MATERIALS AND METHODS • • • • • • • • • • • • • • • • . • • • • • • • • • • . • • • • • • • • • • 4 Site Selection • • • . • • • • • • • • • • • . • . • • • . • • • . • . • . • • . • • • • . 4 Habitat Inventory . • • • • • • • • • • • • . • • • • • . • • • . • • . • • • • • • . • • • • • . 5 Species Information • • • • • • . • . • • . • • . • • . • • • • • • • • • . • • • • • . • • • 6 RESULTS 9 Study Sites • • • • • • . • • • • • • • • • • . • • • . • • • • • • • • • • • . • • • • • • • • • • • • 9 Size Class . • • • • • • • • • • • • • • • • • • • • • • • • • • . • • • • • • • • • • • • • • • • • 22 Growth Rate • • • • • • • • • • • • • • • • • • • • • • • . • • • • • • • . • • • • • • • . • . 23 Seedlings • • • • . • • • . • . • • • • . • • . • . • • • • • . • • • • . • • • • . • • • • • . • 33 Phenology • • • • • • • • • • . • • • • • • . • • . • • • • • • • . • . • • • • • • • • • . • • • • • • 33 DISCUSS ION • • • • • • • • • • • • • • • . • . • . • • • • • . • • . • • • . • • • . • • • • • . • • • . 36 Logging • • • • • • • • • • . • • • • • • • • • . • • • • . • • . • • • • • • • • • • • • • . • • • • • • • 36 Vegetation • • • • • . • • • • • • • . • • • . • • • • • • • • • • • • • • • . • • • • • • • • • • . • • 37 Seedlings . • • • . • • • • • • . • • • • • • • . • • • • • • • • • . • • • • . • • • • • • • • • • • • • 41 Growth • • • • • • • • • • • • • • • • • • . • . • • • • • • • • • • . • • • . • . • • • . • . • • . • • . 43 Population Trends • • • • • • • . • • • • • • • • • • • • • • . • • • • • • • . • • • • • • • . 44 Habitat Preference . • . • . • • • • • • . • • . • • . • . • . • . • • • . • • • • • • • • 45 Cone lud ing Remarks • • • • • • • • • • • • • • • • . • • • • • • • • • • • • • • • • • • • • • • 4 7 BIBLIOGRAPHY 48 v LIST OF TABLES Page Table 1. Location of Royal Palms surveyed for heights and elevations ................................. 18 Table 2. Heights of Roystonea elata determ~ned June, 1982 by 5~" Lietz transit ........................... 19 Table 3. Elevation of Roystonea elata above nearest tramway as determined by 5~" Lietz transit ...•.......... 20 Table 4. Elevation of Roystonea elata above ground level as determined by 5~" Lietz transit ................ 21 Table 5. Measured heights and growt~ rates obtained from numbered trees in the study plots and from seedlings raised horticulturally in West Palm Beach, Florida ................................. 24 Table 6. Roystonea elata: Composite of size classes in the Fakahatchee Strand State Preserve .............. 25 vi LIST OF FIGURES Page Figure 1. Sequence of logging in the Fakahatchee Strand State Preserve .............................. 11 Figure 2. Location of study plots and the boundary of the main population of Royal Palms in the Fakahatchee Strand .......................... 13 Figure 3. Height versus numbers of palms for 1.5 and 3.0 meter size class intervals .................. 27 Figure 4. Growth curve for Roystonea elata .............. 32 Figure 5. Approximate flowering, fruiting and vegetative phases of Roystonea elata ................... 35 vii INTRODUCTION Roystonea elata (Bartram) F. Harper, the Florida Royal Palm, is a slender lofty tree of the low hammock regions of southern Florida. Early this century J. K. Small (1937) described great stands of Royal Palms with heights in excess of 100 feet. Stress from logging, an altered hydroperiod, and encroachment of land developers has left the present native population confined to Everglades National Park, Collier Seminole State Park, and the Fakahatchee Strand State Preserve. The estimated population is approximately 5,000 individuals. During the past ten years emphasis has shifted from purely taxonomic studies of palms to investigations which are more ecological. Read (1974), Vandermeer et al. (1974), Moore (1973, 1977), Banner (1970), and Brown (1976), all of whom have carried out ecological work on palms, suggest the need for more intensive studies on the palm's natural environment. An investigation of the natural environ­ ment is particularly pertinent for the Royal Palm because of it's rare (Ward, 1979) and threatened status (Austin, 1980). Small (1937) documented the presence of the Royal Palm in Florida from the first published description of the palm by Bartram to a fanciful account related by Cook of an "undevistated Florida, canopied by thousands of Royal Palms, with their huge pendent clusters 1 2 of grape-like purple fruits feeding great numbers of wild turkeys~ deer and other game." Small wrote of four main areas of growth of the native palm; I. Royal Palm Hammock in Dade County, which contained rela­ tively few palms; II. the Cape Sable Region, extending from Taylor River to the Cape, which had numerous small colonies; III. the Ten Thousand Islands where the palms were numerous; and IV. the Big Cypress Swamp. He wrote "the fourth area is the hotbed of the Royal Palm; here the growth may be recorded by the thousands. The palms are particularly abundant in the vicinity of Palm Creek and the Facka­ hatchee and Fackaunahatchee". In 1978 the Fish and Wildlife Service commissioned a study of the Royal Palm as a part of a larger project studying the status of endangered plant species in southern Florida. The entire Royal Palm population of southern Florida was under consideration~ This study was undertaken to answer questions which arose during the Fish and Wildlife Service study. Today the Fakahatchee Strand region is still the "hotbed" of the Royal Palm population and as such was chosen as the principal region of investigation for this study. Bailey (1935) did the first comprehensive taxonomic study of Royal Palms. The taxonomic status of Roystonea elata was established by Harper (1946). Since then several authors have discussed Roystonea (Allen 1952, Moore 1977) but no one has examined the Florida popula­ tion specifically. This study examines the status of the Royal Palm population. Numbers of palms, size classes, seedling establishment, elevation 3 of establishment, and associated