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 vegetation are examined. Growth rates are calculated from field and laboratory studies. MATERIALS AND METHODS
All field work was done in the Fakahatchee Strand State Preserve,
Collier County, Florida. The Fakahatchee Strand State Preserve is bounded on the north by Alligator Alley, on the south by Tamiami
Trail, the east by State Road 29 and on the west by the Golden Gates canal system. Between the months of July 1979 and February 1980, nine 10 x 10 m plots were established in the Fakahatchee Strand.
These plots were documented in accordance with procedures outlined by the project officer of the Office of Endangered Species. Data were collected according to the Species Information System of Whitson and
Massey (1978). In November of 1981 seven of the original nine plots were reexamined and additional data were collected on the entire population of Royal Palms located within the Fakahatchee Strand.
Site Selection
The original study plots were established randomly in areas which represented major habitats where the Royal Palm is found in the
Fakahatchee Strand. The mapping of the Royal Palm population and location of extremes in habitat were determined from a helicopter.
The seven plots studied were selected to represent the main body of the Royal Palm population.
4 5
Habitat Inventory
Trees were measured in the 10 x 10 m quadrat with at least two
individuals each estimating cover and then comparing estimates. Shrubs
were handled in the same manner in the 10 x 10 m plot. It was
determined that as many as 50% of the species might be omitted if
smaller quadrats were used for shrubs. Herbs were recorded within a
5 x 5 m plot (Austin et al., 1980).
Plants were recorded as extrapopulational or intrapopulational
and classified as canopy, shrub, or herbaceous. Genus and species
were noted for each plant. Unknown individuals were collected for
later identification. For this study the extrapopulational habitat
was defined as anything outside the 10 x 10 m plot. This was con
sidered more appropriate for the study of Royal Palms because the
plants are scattered over several miles of the Fakahatchee Strand.
To achieve a true "extrapopulational" vegetation analysis according to
Whitson and Massey (1978) it would have been necessary to sample
habitats where the palms did not grow.
Another alteration made in the "Species Information System" was
the definition of dominant taxa in the various strata recognized in
community types. In a subtropical habitat it is rare to find even as much as 20% cover for a plant species. Therefore the 50% cover level
designated by 1Vhitson and Massey (1978) was inappropriate for this
study. To give a better representation of community types the most
dominant taxa in each stratum was used to define the community.
Abiotic factors such as topography, geology and soil were noted 6
but no specific analysis was attempted. Rainfall was measured with a Universal Rain Gauge (Belford Instrument Company #6506) for the three-year period from the start of the original study to the present.
The extremes in water level were measured at each plot with respect to ground level and the elevation of each palm.
Species Information
In the original study the location of each palm was mapped on a grid system within the 10 x 10m plot. The palm's height was determined visually; substrate, phenological information, and associated vegetation were noted. All palms were recorded according to height, defined as the distance from the base of the trunk to the crown. One and a half meter size class intervals were established starting from
0.03 meters to 1.5 meters. Individuals under 0.03 meters (0.1 feet) were noted as grass stage seedlings.
For this study a random survey of the entire Royal Palm population was done. The general health of the population as well as phenological data and an estimate of heights were determined for 500 trees. In the seven study plots, the palms of the original study were located.
Associated vegetation and water conditions were examined. The heights, phenological data and elevation of each individual were determined.
The Fakahatchee Strand was logged for cypress during the late
1940s and early 1950s. Information concerning dates of logging, the logging methods and sequence of logging was collected from local residents and former employees of the logging company, Lee Tidewater
Cypress Company. To establish a growth rate for the Royal Palm, 7
heights of palms in the plots, as well as along roads and logging
tramways were determined. Trees under two meters were measured
directly with a tape measure. For trees over two meters the height
was determined by triangulation using a 5~" Lietz transit. An
estimate of minimum possible growth rate was determined by correlating
the earliest time of establishment according to logging dates for
specific sections and the present heights of the palms, measured by
the transit.
To obtain data that would indicate an optimum height above the
ground for seedling establishment (epiphytic growth), the height or
elevation of the initial point of growth of adult, and seedling palms
was measured by using the 5~" Lietz transit. All measurements were
made from a benchmark that was established at a central point on
Janes Scenic Drive. Elevation of palms in the established plots, as well as palms outside the plots were recorded.
Seedling germination, survival and growth were observed in green
house studies and in the plots. Approximately 100 newly fallen seeds were collected from the Fakahatchee Strand. Half were planted in flats containing vermiculite, ~ inch below the surface. The other half were planted on top of the vermiculite. Both treatments were placed on an open table inside a greenhouse. Automatic watering in the greenhouse kept the vermiculite moist at all times. Percent germination and germination time were noted. Twenty seedlings, approximately one year old, were collected from the outer edge of two of the study plots. These were potted individually in vermiculite and placed in the greenhouse. Growth rate was estimated from these 8 seedlings, the mapped seedlings in the plots, and information from horticulturally grown plants. Seedling survival was documented as a function of the time interval between the original study and the present study .
Data were analyzed statistically according to methods outlined by Sokal and Rohlf (1969). Standard deviation and coefficient of variation were the parameters by which the data were described. RESULTS
Study Sites
The sites selected for this study represent the variation of vegetation and relief in which Roystonea elata is found (Figure 2).
I. Site one: is located west of Royal Palm Park, a county park bisected by Janes Scenic Drive. The area is a mixture of two community types: low hammock, typified by Quercus laurifolia,
Roystonea elata, and Blechnum serrulatum; and mixed swamp, represented by Acer rubrum, Fraxinus caroliniana, Chrysobalanus icaco, and
Blechnum serrulatum. The substrate consists of water-logged muck over Tamiami limestone.
The 10 x 10 m plot established at this site is an example of a low hammock community bordered by sloughs and tramways. A tramway consists of an underlying strata of soft limestone covered by a layer of top soil 2-4 feet thick. They were constructed as a road bed for a narrow gage railroad. This plot is seasonally inundated, with the greatest rainfall during the summer. The plot is usual1y dry during the winter. Most of the original palms in this area are no longer present as a result of extensive logging during Phase I of the logging sequence. (Figure 1)
The first study documented 28 grass stage seedlings and two epiphytic juveniles (0.9 m and 1.0 m) in the plot (Austin et al., 1980).
9 .Figure 1: Sequence of logging in the Fakahatchee Strand State Preserve. Phase 1: 1947-1948 Phase 2: 1948-1950 Phase 3: 1950-1951 Phase 4-7: 1952 l l
:• 2 • • • • • • • • • • c: 6 • (fJ • • • •: Golden ...... • • Gates 3 : 2 • • • I ) 6 ..,
N T Figure 2: Location of study plots and the boundary of the main population of Royal Palms in the Fakahatchee Strand.
e - Study Plots Boundary of the main concentration of Royal Palm Population 13 14
When restudied it was found that 27 of the original seedlings had died. One epiphytic seedling survived (#4), as had the two juveniles
(#2 and #3). All epiphytes were on decaying logs or in detritus at the bases of trees (See Tables 2, 3 & 4 for heights and elevation).
Eleven new seedlings had become established in the plot. One (#2a) was an epiphyte at the base of an oak tree. Ten were in a clump at ground level.
II. Site two is located 20 m southwest of plot one, adjacent to the Royal Palm Park. This 10 x 10 m plot is representative of a mixed swamp bordering low hammock. Acer rubrum dominates the canopy,
Fraxinus caroliniana the subcanopy and Blechnum serrulatum the herbaceous layer. There is a three-inch drop in elevation from plot one to plot two which could account for the difference in vegetation.
The substrate consists of water-logged muck over Tamiami limestone.
The area is seasonally inundated.
Sixty-two ground level, grass stage seedlings and one juvenile
(0.1 m) Roystonea were observed during the first study (Austin et al.,
1980). In the subsequent study, only the juvenile (#11) was found.
No new seedlings were observed.
Plots one and two shared a common seed source, a mature tree
19.96 m tall (#5) south between the two plots. To further sample the area, a 20 x 40 m plot was established; it included plots one and two. In this sample area five additional individuals were documented. All five survived the interval between studies. Three were epiphytic on a cypress stump (#7, #8 and #9) and two were on 15
cypress logs (#6 and #10). Tables 2, 3, and 4 show heights and
elevations. The growth rate for individuals in and around plots
one and two varied from 0.033 to 0.370 meters per year (Table 5).
III. Site three is located 96 m south of Royal Palm Park and
176.3 m west of Janes Scenic Drive. The 10 x 10m plot established
at this site is to determine the effects of old logging tramways on
Royal Palms. One-third of the plot is on the tramway, two-thirds off
the tramway. The section of the plot on the tramway is dominated by
low hammock, represented by Roystonea elata, Myrsine floridana and
Thelypteris interrupta. The approximately two-thirds of the plot off
the tramway is a typical mixed swamp association of Fraxinus
caroliniana, Salix caroliniana, Persea borbonea and Blechnum
serrulatum.
Three adults were found in the plot (#44, #45 and #46) and 19
grass stage seedlings. Three adult trees bordered the plot (#47,
#48 and #49). All individuals except #44 and #47 were presently or
formerly epiphytic. Seedling recruitment was greatest on the one-
half to two-thirds of the plot which was at the margin of the
tramway (Austin et al., 1980). More data were not obtained from
this site because it was destroyed by a local land owner before the
second study.
IV. Site four is located northwest of West Lake, a small lime-
stone sinkhole lake 0.5 kilometers west of Janes Scenic Drive, south of tramway #I-18. Vegetation is characterized by plants of low hammock association, Roystonea elata, Celtis laevigata, Myricianthes 16
fragrans and ferns, bordering a high hammock, represented by Persea
borbonia, Myrsine floridana, Sabal palmetto and Psychotria. The
association grades into swamp and the swamp fringe (Popash and Cut-
grass) of West Lake. The substrate consists of an organic humus
layer 6-12 inches thick on top of limestone. Although no plot was
established, a general survey was made. This area was an example
of a ridge system with associated high hammock vegetation, and is
the highest area examined. The ridge sloped from east to west 1.16
to 5.20%. This area is free from standing water all year. Thirty-
one individuals of heights of 0.1 m to 18.5 m were noted. Trees
in this hammock are more closely spaced than at any other plot.
Because of this, leaf litter is very heavy, often in piles 0.6 -
1 meter deep. Seedling recruitment was very low, in fact no seedlings were found in the hammock. Recruitment was observed at the margins
of the ridge but in low numbers.
V. Site five is located on the southeast corner of Royal Palm
Hammock, adjacent to the south side of tram bi-14, 30 meters east of
Janes Scenic Drive. Vegetation is representative of a low hammock
tending toward a bay head. Dominant species are Quercus laurifolia,
Fraxinus caroliniana, Myrsine floridana and Blechnum serrulatum.
Typically the margin tends toward swamp aRd the center toward hammock. Substrate is primarily muck over limestone.
No 10 x 10 m plot was established at this site during the original study. The site was surveyed and 54 adult individuals of heights of 0.1 to 16.5 m and 72 grass stage seedlings were documented 17
(Austin et al., 1980). When the site was restudied, the status of the
adult trees had not changed and none of the original seedlings could
be found. Fifteen new grass stage seedlings had become established
along the hammock fringe.
VI. Site six is northeast of Royal Palm Hammock on tramway
#III-2, 152.5 meters north of East Main. The vegetation at this
site is low disturbed hammock with mixed swamp adjoining. Represented
at this site are Roystonea elata, Myrsine guianensis, Psychotria sp.,
Ardisia escallonioides and several species of Nephrolepis. The
substrate consists of 20-25 em of organic litter over limestone and
sand. During high water this plot is dry.
This site was placed directly on a tramway and was established
for comparison with plot seven which is adjacent but off the tramway.
The original study documented three adults (#37, #38 and #39) and no
seedlings (Austin et al., 1980). The adults in a subsequent study had
grown an average of 0.278 m per year (See Table 5). Again no seedlings were found in this plot (See Tables 2, 3 and 4 for heights and elevations) .
VII. Site seven is located 15.25 m north and 4 m west of site six. The vegetation in this plot is mixed swamp, with a minimum of disturbed species. The predominant species at this plot are
Roystonea elata, Citrus paradisi, Psychotria nervosa and Thelypteris.
The substrate is muck over Tamiami limestone. During high water this plot has 7-10 centimeters of standing water.
The first study documented four adult palms (#40, #41, #42 and 18
TABLE 1: Location of Royal Palms surveyed for heights and elevations.
TREE It LOCATION TREE II · LOCATION
1 24 Outside Plot 1 1a 25 2 26 Janes Scenic 2a Plot 1 27 Drive, South of 3 28 Royal Palm 4 29 Hammock 5 30 6 31 7 32 East Main 8 20 x 40 m Plot 33 9 at Plots 1 & 2 34 10 35 Woody's Tram 11 Plot 2 36 12 37 13 38 Plot 6 14 39 15a Janes Scenic 40 16 Drive, South of 41 Plot 7 17 Royal Palm 42 18 Hammock 43 19 44 20 45 Plot 3 21 46 22 47 23 Janes Scenic Drive, 48 Outside Plot 3 North of Royal Palm 49 Hammock 19
TABLE 2: Heights of Roystonea elata determined June 1982 by 5~' Lietz transit.
TREE II HEIGHT (m) TREE II HEIGHT (m)
1 2.86 24 13.87 1a 0.18 25 17.62 2 1.55 26 17.40 2a 0.10 27 20.09 3 1.42 28 16.92 4 0.15 29 18.81 5 19.96 30 15.33 6 0.50 31 25.97 7 2.64 32 16.06 8 3.41 33 13.75 9 1.12 34 25.39 10 0.42 35 10.36 11 0.40 36 9.45 12 16.07 37 10.06 13 14.76 38 9.22 14 13.11 39 4.09 15 13.70 40 6.27 15a 12.56 41 10.67 16 15.75 42 10.97 17 20.33 43 3.86 18 18.07 44 12.60 19 13.75 45 9.00 20 19.60 46 1.60 21 20.00 47 12.62 22 17.54 48 0.30 23 21.93 49 1. 90 20
TABLE 3: Elevation of Roystonea elata above nearest tramway as ---- determined by 5~" Lietz transit.
ELEVATION ABOVE ELEVATION ABOVE TREE II TRAMWAY (M) TREE II TRAMWAY (M)
1 0.200 24 0.010 1a 0.200 25 0.080 2 0.050 26 0.003 2a 0.170 27 0.390 3 0.020 28 0.200 4 0.060 29 0.060 5 0.560 30 0.220 6 n.d. 31 0.120 7 0.050 32 0.810 8 0.009 33 0.760 9 0.160 34 0.730 10 n.d. 35 0.000 11 0.080 36 0.000 12 0.260 37 0.000 13 0-. 180 38 0.000 14 0.130 39 0.000 15 0.160 40 0.130 15a 0.100 41 n.d. 16 0.560 42 n.d. 17 0.150 43 0.670 18 0.570 44 0.000 19 0.120 45 n.d. 20 0.370 46 n.d. 21 0.200 47 0.000 22 0.080 48 n.d. 23 0.070 49 n.d. 21
TABLE 4: Elevation of Roystonea elat~ above ground level as determined by 5~" Lietz transit.
ELEVATION ABOVE ELEVATION ABOVE TREE IF GROUND (M) TREE tl GROUND (M)
1 0.17 24 0.74 1a 0.18 25 n.d. 2 0.42 26 n.d. 2a 0.20 27 0.61 3 0.36 28 0.56 4 0.31 29 0.57 5 0.93 30 0.69 6 n.d. 31 0.59 7 0.33 32 0.69 8 0.38 33 0.63 9 0.53 34 0.53 10 n.d. 35 0.00 11 0.30 36 0.00 12 0.60 37 0.00 13 0.81 38 0.00 14 0. 71 39 0.00 15 0.59 40 0.73 15a 0.56 41 0.54 16 0.48 42 0.85 17 0.53 43 0.48 18 0.55 44 0.00 19 0.59 45 0.40 20 0.66 46 0.40 21 0.71 47 0.00 22 0.49 48 0.25 23 0.75 49 0.20 22
#43) and no seedlings. During the subsequent study two of these adults could be measured accurately (See Tables 2, 3 and 4 for heights and elevations). Tree #40 had a growth rate of 0.32 m per year and ~ 43 a growth rate of 0 . 21 m per year (See Table 5).
Plot six had a total numbe~ of 53 species documented as intra populational and extrapopulational. Plot seven had 41 species. The greater number of species in plot six was predominantly in the herbaceous layer. The difference in elevation between plot six and plot seven was 0.13 m. The lower elevation in plot seven and the standing water for part of the year is believed to account for the difference in vegetation.
The data remaining in tables 2, 3 and 4, not recorded with reference to specific plots, were collected at points along Janes
Scenic Drive, East Main, and Woody's Tram. These data were collected during the general survey and used to supplement data from the plots as well as recorded for future studies. (See Table 1 for locations)
Size Classes
The Royal Palm population in the Fakahatchee Strand is estimated at 3,500 individuals. This figure was determined from counts on the ground and from a helicopter. The general survey of the population was made in the greatest concentration of trees (Figure 2) . Heights of 518 trees were documented. Two hundred and forty-two or 46.72% of the 518 trees were grass stage seedlings, forty-six or 8.88% of the individuals surveyed were 0.03- 1.5 meters and four or 0.008% of the trees were 1.5- 1.8 meters tall. Heavy herbaceous and shrubby 23 cover made accurate counts of seedlings and juveniles up to 1.8 meters tall in the general survey impossible, therefore they were excluded from Figure 3 and Table 6.
A composite of numbers of trees in each of the remaining size classes is shown in Table 6. Figure 3 is a representation of the data in Table 6. The graph shows a decrease in the number of individuals as height increases. This is a smooth curve if an increase in numbers between 13.5 - 18.0 meters is excluded. The increase in the number of individuals at 13.5 - 18.0 meters coincides with the period of logging approximately 30 years ago. The phases of logging account for the span in size (Figure 1).
Growth Rate
Although the growth rate for seedlings germinated in the green house was 3 em per year, the mean growth rate for seedlings was taken to be 4.2 em per year. This was the rate for seedlings monitored in the field. The lower rate of growth in the greenhouse was con sidered a function of the planting and transplanting processes. The transplanted seedlings from two study plots had a very high rate of mortality due to the transplanting process; therefore they were not used to determine growth rates.
Much of the initial growth in a palm seedling is lateral rather than vertical. This increase in diameter establishes a base from which internodal growth proceeds. This is part of the reason for what appears to be slow growth in a seedling during its first years. The growth rate for seedlings is lower than Bannister's 24
TABLE 5: Measured heights and growth rates obtained from numbered trees in the study plots and from seedlings raised horticulturally in West Palm Beach, Florida. Tree numbers 1-11 were measured for a three-year period, numbers 38-43 for a 2.42 year period and numbers S-1 through S-18 for a 3.5 year period.
ORIGINAL NEW CHANGE IN RATE TREE II HEIGHT (m) HEIGHT (m) HEIGHT M/YEAR
2a Seedling 0.100 0.100 0.033 4 Seedling 0.150 0.150 0.050 11 0.100 0.400 0.300 0.100 6 0.400 0.500 0.100 0.033 10 0.300 0.420 0.120 0.040 3 0.900 1.420 0.520 0.173 9 1.000 1.110 0.110 0.037 2 1.000 1.550 0.550 0.183 1 2.000 2.860 0.860 0.287 7 2.200 2.640 0.440 0.147 8 2.300 3.410 1.110 0.370 43 3.350 3.860 0.510 0.211 39 3.660 4.090 0.430 0.178 40 5.490 6.270 0.780 0.322 38 8.530 9.220 0.910 0.377 s- 1 Seedling 0.100 0.100 0.029 s- 2 Seedling 0.090 0.090 0.026 s- 3 Seedling 0.200 0.200 0.057 s- 4 Seedling 0.170 0.170 0.049 s- 5 Seedling 0.170 0.170 0.049 s- 6 Seedling 0.170 0.170 0.049 s- 7 Seedling 0.240 0.240 0.069 s- 8 Seedling 0.200 0.200 0.057 s- 9 Seedling 0.180 0.180 0.051 S-10 Seedling 0.150 0.150 0.043 S-11 Seedling 0.240 0.240 0.069 S-12 Seedling 0.170 0.170 0.049 S-13 Seedling 0.130 0.130 0.037 S-14 Seedling 0.110 0.110 0.031 S-15 Seedling 0.130 0.130 0.037 S-16 Seedling 0.100 0.100 0.029 S-17 Seedling 0.110 0.110 0.031 S-18 Seedling 0.100 0.100 0.029
x=O .101 25
TABLE 6: Roystonea elata: Composite of size classes in the Fakahatchee Strand State Preserve.
SIZE CLASS NUMBER OF PERCENT OF (METERS) INDIVIDUALS POPULATION
30.0 1 0.5
24.0- 27.0 3 1.5
21.0 - 24.0 2 1.0
18.0 - 21.0 9 4.0
16.5 - 18.0 20 8.5
15.0 - 16.5 32 14.0
13.5 - 15.0 18 8.0
12.0 - 13.5 10 4.0
10.5 - 12.0 11 5.0
9.0 - 10.5 10 4.0
7.5- 9.0 15 7.0
6.0- 7.5 13 6.0
4.5 - 6.0 20 8.5
3.0 - 4.5 26 12.0
2.0 - 3.0 36 16.0
TOTALS 226 100.0% Figure 3: Height versus numbers of palms for 1.5 and 3.0 meter size class intervals. (Based on data in Table 6) .... Distinguishes post-logging and prelogging period. 27
-C'.l c z (!) (!) C'.l 0 ...J - w cr 0.. • • 00 .... • I "' • "" • - - -.-• I E"" • • t.n • I .: • - (!) - z (!) I -"" (!) = 0 ...J C'.l .... Vl 0 - 0.. II 1 I I
-~ 28
(1970) rate for Euterpe (6 em per year). This comparison is for reference only as Euterpe is a tall, slim, rainforest species and
Roystonea is a larger tree (greater in diameter) and not subject to the rainforest habitat. The seedlings considered here were monitored from germination through their first year of growth.
The mean growth rate for young trees (palms monitored from their first year of growth until sexual maturity) was 10.5 em per year
(Table 5, x=0.101 meters per year). This figure was an average from several sources, including a wide range of age classes. The horti culturally grown plants were placed in this catagory because the rates for these palms reflect a combination of seedling and juvenile growth.
In an effort to determine if growth rates differed according to substrate, growth rate values were calculated for palms (located in the plots) according to where they were growing. The seedlings monitored from ground level exhibited the lowest growth rate (4.2 em per year). Only seedlings, which have a lower rate of growth, were observed at ground level. The rate for a 3.5 year period, (from the time of germination) for the horticulturally grown seedlings, ranged from 2.6 em to 6.9 em per year. This averaged 4.4 em per year for the
18 individuals (#S-1 - S-18, Table 5). Individuals whose heights, at the beginning of the study, were 0.1 - 2.3 meters had growth rates of 3.3- 3.7 em per year. This range in values is probably due to the age of the palm when the height monitoring was started, the substrate on which the palm was growing, and seedling variation.
Figure 4 suggests that growth rate increases with age. Therefore 29 older trees grow faster than younger trees and seedlings (which exhibit lateral growth initially). Epiphytic palms and those that dropped on trams have a better chance of establishment and subsequent germination than seedlings which have landed on marginal habitat such as tramway edges, slough and hammock margins. There does not appear to be any significant difference in growth rate between epiphytic individuals on stumps, logs, knees or tree bases. A slightly higher rate was noted for cypress stump epiphytes but this could be attributed to their greater size at the onset of the study. Individuals monitored on stumps were a meter or better in height when the study started. A calculation of growth rate (meter per year) per meter of initial height showed no significant difference . • Adult trees exhibited the greatest growth rate. The growth curve in Figure 4 increases rapidly from 0 to 9 meters and levels off there- after. Nine meters is the average height of a sexually mature individ- ual. It appears that the growth rate levels off at this period in the tree's life history. The outside limit of the curve (0.5 meters per year) was an estimate of growth rate for the trees which survived logging or were assumed to have established themselves on tramways immediately after logging. By knowing the age of the tramways and phases in which the Fakahatchee was logged, the age of a tree was estimated. This age estimate was then compared to the height of trees on or near the tramway to determine a rate. As the maximum possible age of the tree was used, the growth rate estimate isa .minimum value.
Although this figure is a crude estimate of the growth rate, it was 30
considered valid for the purposes of this study.
An approximate growth rate for Roystonea elata was determined by
several different methods. The phases of logging were correlated
with heights of trees located in each phase. This resulted in an
approximation of minimum possible growth rate for trees in a given
logging phase. These figures were for general reference since the
exact time of establishment for any given tree was not known.
Secondly, a yearly growth rate was determined from a comparison of heights measured during the first study and heights determined in this
study. These were taken during a 2.42-3.00 year period for 15 trees ranging from seedlings (0.025 m) to 8.53 meters (See Table 5). Lastly a study was made of 18 seedlings germinated from seed 3.5 years ago.
An average growth rate of 0.044 m per year was determined from these horticulturally raised juveniles (Table 5).
The growth curve on Figure 4 is a composite of growth rates for each size class from the three sources (seedling, juvenile, adult).
This curve indicates an increase in growth rate as height increases.
A maximum rate of 0.50 m per year is noted as the outside limit of the curve. This was the minimum possible growth rate for trees on logging tramways as indicated in Phase I.
Elevation of seedling establishment was found to be a function of location, maximum elevation of water at the time the fruit was dropped, and the time of year the fruit drop took place. There was no signifi cant statistical correlation of elevations between locations or size classes of established seedlings. Figure 4: Growth curve for Roystonea elata. (Based on data in Table 4). 32
0
..
0... •
~
-::! a;.. -.5 <0 ....c-o ~ c:
~
II') ... =-
------·~------~----r-----+-----~-----r--~~0 <0 Ill 'It M " N 0 6 0 6 0 33
Seedlings
For the two scheduled plantings of fifty seeds each, successful
germination was 4% at the 1.3 em depth and 2% at ground surface.
Germination time varied between 17 and 22 days. The low rates of germination were attributed to a nonshaded light regiment. The two plantings were repeated, but under low light conditions. Successful germination under low light at 1.3 em depth was 62% and under low light at ground surface was 48%. Germination time was the same.
Seedling growth rate was determined from two sources. Trans planted seedlings were monitored for 6 months. The 30% of the seedings that survived transplanting indicated a growth rate of
3 em/year (extrapolated for one year) . The growth rate for the mapped seedlings in the study plots was estimated at 4.2 em/year, averaged for the three year time span in which they were monitored.
The average growth rate for the 18 horticulturally raised individuals was 4.4 em per year.
Phenology
Phenology data for a three year time period is illustrated in figure five. Figure 5: Approximate flowering, fruiting and vegetative phases of Roystonea elata. Black indicates month in which phenological phase is present. 35
a;, 'CD =- c: 'CD ·- = ed a;, -a;, 31: 'CD - -:::::1 -a;, = ~ ~ - ==- DISCUSSION
The Royal Palms in the Fakahatchee Strand were documented in the
1920's by J. K. Small (1937), although he cited no accurate count for
that time period. One of the first large scale disturbances to the palm population was in the early 1930's when large numbers of palms were removed to landscape the Hialeah Race Track in Hialeah, Florida
(Tebeau, 1966). The population remained relatively undisturbed for a number of years until logging was started in the mid-1940's.
During the years of logging, palms were cut down to make way for trams and skids by which millions of board feet of cypress were removed
(personal communication Swanson, 1979). The number of adult palms killed is unknown. In addition, the cutting methods used in this kind of logging destroyed seedlings and juveniles. Mel Finn (1966) cites Beard, et al. 1948, estimating that approximately 10,000 palms survived the logging.
Logging
The initial phases of logging involved surveying and clearing an area for a dragline to be located. The dragline's job was to construct a tramway or road bed from which to operate a narrow gage railroad. The underlying strata of the area was primarily limestone
(Tamiami Formation). Over the rock was a layer of top soil 0.6- 1.2
36 37 meters thick, consisting of light loam mixed with decaying vegetation.
There was usually sufficient soil for the dragline to construct a road bed before striking rock (Prestridge, 1947). Rarely did the logging company haul in fill. During the initial construction of tramways, cypress trees were first girdled. Once the tracks were completed, the logging was then started, trees were felled, cut into 32 foot lengths and skidded to the side of the tramway.
Today the logging tramways are still visible although overgrown with dense vegetation. The drainage canals created by the dragline when the road beds were layed are intact and are 4-5 feet deep during periods of high water. These canals act to separate the tramways from the surrounding swamp. The old skidder trails have been eroded away or obscured by vegetation.
The logging activity in the Fakahatchee Strand had a number of significant effects. Removal of the once-extensive cypress forest allowed expansion of a mosaic of plant communities, primarily mixed swamp and disturbed low hammock. The tramways which were consider ably higher than the surrounding swamp created additional habitat for hammock species, specifically the Royal Palm. The tramways also acted to slow the flow of water southward, first by blocking sheet flow and second by delaying water in the adjacent ditches and canals.
Very often these ditches and canals hold water after the surrounding swamp has begun to dry up.
Vegetation
The prelogging vegetation of the Fakahatchee Strand region was 38
described by Davis (1943) as mixed swamp. More specifically it was a cypress dominated swamp with mixed hardwoods (Acer rubrum, Salix caroliniana, Quercus laurifolia and Fraxinus caroliniana) with inter spersed low hammock (Myrica cerifera, Persea borbonia, Magnolia virginiana, Morus rubra, Ficus aurea). After the cypress were removed, the maple, oak, willow, and other swamp hardwoods dominated.
The mixed swamp forest which dominates the Fakahatchee Strand today is a mixture of many tree and shrub species. The elevation throughout the strand varies from areas which are inundated during most of the year to areas which are seldom flooded. Most of the region is seasonally inundated. In these inundated areas called mixed swamp, hardwood species such as sweet bay (Magnolia virginiana), strangler fig (Ficus sp.), red maple (Acer rubrum), cabbage palm
(Sabal palmetto) and wax myrtle (Myrica cerifera) are abundant. The deeper areas are dominated by popash (Fraxinus caroliniana), pond apple (Annona glabra), willow (Salix caroliniana), and cypress
(Taxodium distichum). Growing among the tree species are shrubs and herbs such as buttonbush (Cephalanthus occidentalis), dogwood
(Cornus foemina), lizards tail (Saururus cernuus), and a variety of grasses and sedges. The hammocks of the Fakahatchee Strand grow on relatively high ground and adjacent to seasonally flooded areas.
Hammocks contain hardwoods, palms and a variety of southern temperate and tropical species. Of the different hammock types the high tropical hammock is the least abundant. When present, it is typified by gumbo limbo (Bursera simaruba), laurel oak (Quercus laurifolia), 39
dahoon (Ilex cassine), Myrsine floridana, and wild coffee (Psycotria
sulzneri). Royal palms are found in association with all the high
hammock. Often palms are abundant enough to warrant Davis' (1943)
designation of Royal Palm Hammocks. Low hammocks are more abundant
in the Fakahatchee Strand and constitute the major habitat where
Royal Palms are found. These hammocks are located adjacent to
swamps, or in wet prairie and marsh. An abundance of higher hammock
trees, bays and ferns change the character of a swamp to a low hammock.
Concomitant with the establishment of such trees is a slightly higher
elevation.
The tramways were colonized primarily by low hammock species. At
present, because of both human and animal use, the vegetation of the
tramways is more properly termed disturbed low hammock. Tropical fruit
trees (guava, citrus, avocado), a remnant of logging days, and road
side weeds and shrubs grow beside characteristic low hammock species.
Royal Palms are abundant.
Plots one and five were the most favorable sites for palm estab
lishment and growth. The remnant logs, stumps, and knees of the logged
cypress community as well as the adjacent tramways provided proper
substrate for palm seeds. Water levels were moderate, and periods of
standing water were short. Maples and oaks of the low hammock vegeta
tion, which become established on high ground, provided substrate for
seed establishment and shade for germinating seedlings. Both plots had a low number of species (29 for plot one) and high number of
seedlings. Seedling survival was greatest in plot 5. 40
Plot two was very similar to plot one but had longer periods of
standing water and higher water levels . This plot had 33 species.
Seedling survival was very low.
Plot three had an even greater number of species (38). This
higher species richness was a function of the combined low hammock/
mixed swamp nature of the plot. Seedling recruitment was greatest on
the 2/3 of the plot off the tramway. Although there were numerous
seedlings at the edge of the tramway, few seedlings could be located
on the tramway itself. This was a well traveled area (animals and man),
making seedling establishment difficult.
Plot four had the greatest number of adult trees but low seedling
survival. This site is located along a high rock ridge, which since
logging, has been completely covered by Royal Palms. Litter was too
dense for seedling establishment anywhere except the margins of the
site.
Plot six had the highest number of species (53). Most of these
species were herbaceous which do not appear to hinder palm establish ment. This was not a well-traveled tramway and had a number of young
trees, less than 9 meters tall. As the number of reproductively mature trees increase, the number of palms in this site as well as
other untraveled tramways, will increase. These tramways could
become as densely populated as the high hammock sites.
Plot seven, adjacent to plot six, had no seedlings reported
during the three year study period. This plot was a typical mixed
swamp and as such, too wet for seedling establishment. 41
Seedling~
In the Fakahatchee Strand, Royal Palms start to drop their f ruits in May (Figure 5) . This corresponds to the beginning of the rainy season and with the increase in water levels. The fruit falls to the ground, or drops into the slough or adjoining ditch. Ripe Royal
Palm fruits can float in the field and laboratory for several weeks with no harm to viability. This ability to float presumably explains the epiphytic nature of many of the Royal Palms observed in the
Fakahatchee Strand. Small (1937) noted the proximity of palms to water courses and suggested the possibility of fruits floating or being forced up rivers by storms or hurricanes.
Palms are epiphytic on logs, cypress stumps, cypress knees and the edges of tramways. Since the seeds become established during periods of high water, the surviving seedling palms stand above the water. As they grow larger these palms establish a root system that maintains the trunk of the palm at the elevation where it was originally established.
After logging, the abandoned tramways proved to be an ideal habitat for the Royal Palm. Aside from the tramways, colonization was highest in the areas that had been most heavily logged. These areas correspond to places in the present day slough system that show mod erate water levels (Figure 2). The mixed swamps north of the main boundary of the Royal Palm population were in considerably deeper slough and not therefore conducive to palm growth.
Roystonea seeds germinate quickly but subsequent growth is slow. 42
I found the maximum germination rate to be 62 percent in 17-22 days.
This compares to Sento's (1971) rate of 50 percent germination in 8 days (the smallest number of days from planting to germination). It is not known how long seeds retain viability under unfavorable condi tions, since favorable conditions were maintained in this study.
Rotting fruits and seeds were observed in this study during periods of prolonged emersion in water.
Seeds commonly germinate under complete canopy cover and therefore do not appear to require direct light for germination and subsequent growth. This is consistent with conditions found in the Fakahatchee
Strand. In the greenhouse, germination was significantly greater under low light conditions. It is not unusual to see young Royal Palms grow ing in, full shade at the bases of large oak trees.
Roystonea seems to be sensitive to the environmental factors of rain and temperature. Fruit drop begins with the start of the rainy season and the onset of high humidity and warm temperatures. Sento
(1971) found the optimum temperature for seed germination to be 30°C.
In the study plots germination was successful during the summer months while seeds dropped in plot 5 during December showed little or no viability.
Planting depth from 0 to 1.3 em does not seem to be a factor in germination. Sento (1971) found clay loam to be the most satisfactory planting medium for Roystonea seeds. The use of vermiculite in this study was also successful. Seeds in the field are observed to germi nate on the surface, or just below layers of leaf litter. The seeds 43 found on the ground surface are often in clumps and are probably a product of animal dispersal. Raccoons and oppossums are known to ingest the fruits, and elsewhere birds spread them (Leek, 1969).
Growth
As a Royal Palm increases in height there is an increase in the number of fronds. Palms one meter tall have two fronds. This increases to as many as twenty-three fronds on a palm at canopy level.
Bannister (1970) suggests that higher light intensities produce a change in growth and metabolism. This is consistent with the data on the increase in growth rate up to reproductive age and/or canopy height.
(Figure 4)
The low hammock habitat in which Roystonea is found is variable in canopy composition and height. The average canopy height is typically below 12 meters. Using an escalating growth rate from the three size classes previously outlined (seedling, juveniles and adult) it would take 25 years to reach reproductive size, and 31 years to reach the canopy. Many of the palms surveyed in the phase I region of logging are now well above canopy level.
The maximum attainable height for Roystonea elata has not been determined. Small (1937) documents sightings of Royal Palms, 27.5 and
36.5 meters tall, by early naturalists such as Thomas Nuttall, J. G.
Cooper, and William Bartram. There is one palm in the Fakahatchee
Strand which is approximately 30 meters tall. There is no evidence that growth ceases at a certain point in the tree's lifetime although limiting factors do exist. Most notably these factors are wind, storms, 44
and cold. A 30 meter Royal Palm towers over the surrounding vegeta
tion. In very high winds the trees have been known to break at mid
trunk and in storms they are susceptible to lightning strikes. Cold
is a factor which effects all size classes. A drop in temperature to
near or below freezing will cause damage to the meristem. Dent Smith
(1964) documents cold damage in cultivated Royal Palms. Severe damage
usually results in the death of the tree although in some cases
recovery does occur, as many as eight months later. The winter of
1979 damaged six Royal Palms (13.5 - 15 meter size class) along Janes
Scenic Drive. Only two survived. Damage occurred most significantly
to juveniles up to 6 meters tall located in the sloughs. Temperatures
were lowest in these areas.
Population Trends
The size classes illustrated in figure 3 show several trends in
the present Royal Palm population. Fruit drop and subsequent seed
germination are very high. Large numbers of germinated seeds were
observed in all three years of the study. The decrease in the number
of individuals in size classes from 2.0 to 7.5 meters is due to natural mortality. As the curve depicting the number of individuals descends,
the population stabilizes at sizes between 9.0 13.5 meters. This
size range is reproductively active and in the years to come will be
the foundation of the population.
The rise in the curve from 13.5 to 18.0 meters coincides with the
intense period of logging illustrated in figure 1. The dramatic rise
in numbers of individuals is due to the colonization of new habitat 45
opened by logging. Tramways and mounds of soil and vegetation were
available in stages as areas were abandoned and the loggers moved to a new area. Royal Palm seedlings compete well with weedy species and over a period of several years can outlast surrounding herbaceous vegetation. This competitive ability has allowed the palms to be good colonizers in a habitat that is more easily invaded by disturbed species.
The decrease in numbers of individuals from 18-30 meters is due to logging mortality. A lower number of trees in the 21 -27 meter range is a result of the logging process, particularly clear cutting.
Size classes increase from 1.5 to 3.0 meters on the graph because of low numbers of trees in 1.5 m intervals. The three meter intervals are more accurate graphically and also illustrate more clearly the gap in numbers of individuals between the 16.5 - 18.0 meter and 18.0- 21.0 meter intervals. These gaps are due to destruction of seedlings and juvenile trees during the initial phases of logging. If the Fakahat chee Strand had not been logged, the curve, ideally, would have been smooth and descending to a level slightly lower than the 9.0 - 13.5 meter size classes illustrated in figure 3.
Habitat Preference
The elevation of seedling establishment, both above the ground and above the nearest tramway (Tables 3 and 4), was analyzed statis tically to determine variation in the data and to possibly correlate certain environmental conditions and palm size classes. Elevation, above the ground, of seed establishment and subsequent germination 46
were a function of the time of the year at which fruits dropped and the maximum level of water during that particular year. (Fruit drop and germination occurs potentially all year long.) There was no· correlation between plots or substrate (cypress stumps, cypress knees, mounds and tree bases) with respect to seedling establishment. Also, there was no correlation between the elevations of establishment of individuals of the same age; as different plots had different water levels. Further statistical analysis was not attempted because of the wide ranging values.
Water levels can fluctuate dramatically from one year to the next.
This accounts for the wide range of palm elevations, even in the same plot. This can also explain higher rates of mortality of germinated seedlings in a wet year which follows a dry year. Seedlings which become established at or near ground level will die if immersed the following year. This was observed specifically in plots 1 and 5.
Seeds floated to locations which were equal or higher than the nearest tramway (as compared to the established bench mark). This implies a preference for high ground which is contrary to the Royal Palm's reputation as a "swampy" plant. The Fakahatchee Strand has long been referred to as a Cypress-Palm swamp instead of a cypress dominated mixed swamp. According to Beard (1944), a palm swamp is a transition from the forest of a seasonal swamp to herbaceous vegetation marked by a zone of scrubby woodland in which palms are dominant. The areas where these palms grow are not transitional with respect to the swamp, but are pockets of high ground scattered within the swamp. At no time 47
has an adult tree been observed living in the water, and there is no
colonization of areas of great seasonal inundation. High water levels appear to only benefit seed establishment.
Concluding Remarks
The present population appears to have stab~ized in response to the ecological conditions found in the Fakahatchee Strand today.
Temperature extremes will always have an adverse effect on the popu lation, but it is something which cannot be controlled. Factors which we can influence are water levels and development. Water has been a critical factor in the overall health of the Fakahatchee Strand. In
1973 the Gulf America Corporation dug drainage canals on the western edge of the Fakahatchee Strand as part of their Golden Gates housing project. The water levels in the prairie and adjacent strand were lowered as much as 0.6 m and seasonal flooding was eliminated
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