Report SFRC-87/03 

0 Id F ield Succession 

in Everglades 

National Park 

I rnsiliir~i~ir NNII DII...YI*I 01 

I*' Irn.,O. 

3 1199 01 124 6579 

Everglades National Park, South Florida Research Center, P.O. Box 279, Homestead, Florida 33030 
OLD FIELD SUCCESSION 

IN 

EVERGLADES NATIONAL PARK 

National Park Service 

South Florida Research Center 

Everglades National Park 

Homestead, Florida 33030 

' L 0 jgsg 

F. I. U. URBAN &i REG. DOCS. LIBRARY 
KIUUSS, Pamela. 1987. Old Field Succession in Everglades National Park. 

South Florida Research Center Report. ~~~~-87/03. 
TABLE OF CONTENTS 

LIST OF FIGURES ................................................ ii 

LIST OF TABLES ........................................................ iii 

ABSTRACT .............................................................. iv 

INTRODUCTION .......................................................... 1 

MATEKIALS AND METHODS ................................................. 4 

Study Area .......................................................... 4 

Study Plots ......................................................... 4 

Vegetational Analyses .............................................. 7 

rnSULTS ............................................................... 12 

Study Plots ......................................................... 12 

Study Plot 1 ................................................. 12 

Study Plot 2 ........................................................ 14 

Study Plot 3 ........................................................ 14 

Study Plot 4 ........................................................ 15 

Study Plot 5 ........................................................ 15 

Study Plot 6 ........................................................ 16 

Study Plot 7 ........................................................ 16 

Study Plot 8 ........................................................ 16 

Study Plot 9 ........................................................ 17 

Study Plot 10 ................................................. 18 

Study Plot 11 .................................................. 18 

Study Plot 12 ....................................................... 18 

Study Plot 13 ....................................................... 19 

Study Plot 14 ....................................................... 19 

Study Plot 15 ....................................................... 20 

Study Plot 16 ....................................................... 20 

Study Plot 17 ....................................................... 21 

Study Plot 18 ....................................................... 21 

Study Plot 19 ................................................ 21 

Study Plot 20 ....................................................... 22 

Study Plot 21 ....................................................... 23 

Species Composition ................................................. 23 

Study Plot Similarities ............................................. 24 

Canopy Cover and Vegetation Size Class .............................. 30 

Abundance. Diversity and Evenness ................................ 30 

Canopy height and Litter Cover ................................... 38 

Hydrology ........................................................... 38 

Community Structure. Agricultural History. 

Soil Type and Hydrology ........................................... 41 

The Effects of Exotic Species ................................. 41 

DISCUSSION ............................................................ 50 

CONCLUSIONS ........................................................... 57 

ACKNOWLEDGEMENTS ............................................... 58 

LITERATURE CITED ...................................................... 59 

APPENDIX 1 ............................................................ 63 
LIST OF FIGURES 

Figure Page 

1. Map showing location of the study area........................... 5 

2. Map showing location of the 21 study plots...... ................. 6 

3. Orientation and locations .of subsamples within 

each study plot.................... ............................ 8 

4. The number of species that occurred in one or 

more study plots............................... ................ 25 

5. Dendrogram showing clusters of study plots 

generated by cluster analyses based on 

Sorensen's Coefficient of Similarity ........................... 29 

6A. Mean and range of percent cover for each 

vegetation size class in study plots 1-6.......................31 

6B. Mean and range of percent cover for each 

vegetation size class in study plots 7-12......................32 

6C. Mean and range of percent cover for each 

vegetation size class in study plots 13-18.....................33 

6D. Mean and range of percent cover for each 

vegetation size class in study plots 19-21.....................34 

7. The relationship between canopy presence or 

absence and number of species .................................. 43 

8. Linear regression of percentage of exotic 

species against total number of species ........................ 46 

9. Linear regression of percentage of exotic 

individuals against total number of species .................... 47 

10. Linear regression of percentage of exotic 

individuals against species evenness...........................48 

11. Linear regression of percentage of exotic 

individuals against species diversity .......................... 49 
LIST OF TABLES 

Table Page 

1 . Size class sampling areas and designations ....................... 9 

2 . Summary of species richness and historical and 

physical characteristics of each study plot .................... 13 

3 . Species which occured in more than 50% of all 

study plots .................................................... 26 

4 . Study plot similarities based on the Sorensen 

Coefficient of Similarity ...................................... 27 

5 . Total numbers of individual plants in each study plot ............ 35 

6 . Diversity. evenness and percent exotics in each 

study plot ...................................................... 37 

7 . Mean tree height and percentage litter cover data 

for each study plot ............................................ 39 

8 . Summary of hydrological data during the seven month 

wet season from April to October during 1978 and 1979 .......... 40 

9 . Kesults of Mann-Whitney U tests comparing study plots ............ 42 

10 . Sumary of linear regression analyses ............................ 44 

iii 
ABSTKACT 

A characterization of successional vegetation patterns on abandoned 

farmland i11 the Hole-in-the-Donut area of Everglades National Park was 

performed. Vegetative community composition and structure was examined in 

detail in 21 study plots located throughout the study site. Successional 

assemblages are described qualitatively and quantitatively. Distinct 

community types are defined using methods that emphasize site-to-site 

comaprisons. The relationship between vegetation and substrate, farming 

history, hydroperiod, and spatial arrangement was examined. Results were 

used to summarize and predict trends of old field succession on abandoned 

farmland in southern Florida. Post-farming vegetation patterns do not 

resemble prefarming conditions. Successional forest, frequently dominated 

by exotic species, is a relatively new community in southern Florida. It 

is likely a fiual stage in secondary succession on abandoned farmland. 
INTRODUCTION 

The effects of man and management decisions on ecological 

change in southern Florida are well documented (Carter, 19'74; 

McCluney, 1969). These ecological changes become more apparent with 

every passing decade. With local land use ordinances (Metropolitan 

Dade County Master Plan, 1979; East Everglades Planning Study, 1980) 

that lead to land use changes in agricultural areas, there is a 

growing importance to understand succession on abandoned farmland. 

The results of this research together with the findings of other 

studies begin to answer questions about successional trends on oldfields in southern Florida. 

The mechanisms and processes related to old-field succession 

have been the subject of detailed regional studies in the 

southeastern United States (Oosting, 1942; Keever, 1950; McCormick 

and Buell, 1957; Odum, 1960). In southern Florida, Davis (1943) 

discussed the potential utilization of Everglades for farmland. 

Egler (1952), in his paper on the management of the southeastern 

Everglades discussed and predicted trends of secondary succession on 

abandoned farmland. Robertson (1953, 1955) qualitatively described 

early sera1 stages on abandoned Tarmland in Everglades National Park. 

Alexander and Crook (1973) discussed a successional scheme based on a 

study of long term qualitative changes of old fields in the Hole-inthe-Donut (Donut) area of Everglades National Park. Hilsenbeck 

(1976) quantitatively studied early stages of old-field succession in 
the Donut and also provided data on the relative effects of 

management techniques on initial successional assemblages. Meador 

(1977) investigated the role of mycorrhizae in influencing succession 

in the Donut. Loope and Dunevitz (1981) reevaluated vegetation 

changes in areas that Hilsen%eck (1976) studied as well as reporting 

on succession following selected management in the Donut. They also 

discussed the establishment of exotic trees on abandoned farmland. 

Ewe1 -- et al. (1982) provided a detailed ecological study of Schinus 

terebinthifolius, the most abundant exotic tree in the Donut. 

~lthiu~h there is scientific literature describing the major 

communities that occur in southern Florida (Harshberger, 1914; 

Harper, 1927; Davis, 1943; Craighead, 1971), mature abandoned 

farmland yegetation has not been thoroughly described. Robertson 

(1953, 1955) , Alexander and Crook (1973) , Hilsenbeck (1976) , Meador 

(1977), Loope and Dunevitz (1981) and Ewe1 -- et al. (1982) referred to 

abandoned farmland assemblages dominated by tree species including 

Persea borbonia, Ilex cassine, Myrica cerifera, and Schinus 

terebinthifolius. 

The general purpose of this research is to quantitatively and 

qualitatively describe these mature successional forests. The 

specific objectives are: to identify community structure and 

*' --. 

composition in the Hole-in-the-Donut; to define community tries in 

the present vegetation mosaic; to assess site-to-site differences in 

sera1 assemblages that will provide information on successional 

trends; to examine relationships between vegetation and substrate, 

farming history, hydroperiod and spatial arrangement; to provide 
baseline successional data; and to establish permanent study plots 

for future study of old-field succession in Everglades National Park. 
MATERIALS AND METHODS 

Study Area 

The study area is located in the southern Everglades. It 

consists of the Hole-in-the-Donut and nearby abandoned farmland in 

eastern Everglades National Park (~i~ure 1). The.Hole-in-the-Donut 

comprises approximately 4000 hectares of abandoned farmland occupying 

portions of Townships 58 and 59 S, Range 36, 364, and 37 E. The area 

is located west of Royal Palm Visitor Center and is bound on the 

south and east by the Old Ingraham Highway and to the north by Long 

Pine Key. '~bandoned farmlands adjacent to Pine Island and south of 

the Everglades National Park Visitor Station are also included in the 

study area. 

Climate, ecology, hydrology, and geology of the southern . Everglades have been described by Craighead (1971) , Egler (1952) , 

Davis (1943), and Robertson (1953). Site-specific accounts of prefarming vegetation in the Hole-in-the-Donut have been described by 

Hilsenbeck (1976). 

Study Plots 

Twenty-one permanent plots were established within the Donut 

during 1978 and 1979 (Figure 2). Study plots were selected in old 

fields representing varying hydroperiods, substrates, ages and 

vegetative compositions. Plot locations were selected for ease of 

accessibility and avoidance of edge effects. All plots were oriented 

on a north-south or east-west axis. The corners of each plot were 

marked by a blue-tipped reference pole. All study plots were 5 x 20 m 


(100 m'. Plot size was consistent with other research studies in 

Everglades National Park (Olmsted, Loope and Hilsenbeck, 1980). Exact 

plot locations were filed in the plant ecology files, South Florida 

Research Center, Everglades National Park. 

Vegetational Analyses 

Vegetation was analyzed using the quadrat method of MuellerDombois and Ellenberg (1974). For ease of analysis, vegetation was 

sampled in three size (height) classes: <60 cm high (size class 

one), <2 m and >60 cm high (size class two), and >2 m high (size 

class three). Size classes one, two and three represent herbaceous 

plants and grasses, shrubs and saplings, and trees and tall shrubs, 

respectively. Size class one was sampled in sixteen 0.25 m2 

subsamples systematically located throughout the study plot. Each 

0.25 rn' is designated as a subquadrat. Size class two was sampled in 

four 5 m2 subsamples systematically located within the study plot. 

Each 5 m' is designated as a subplot. Size class three was sampled 

in four 25 m' subsamples. Each 25 m' was designated as a quadrat; 

all trees and tall shrubs were sampled in the study plot. 

Orientation and location of subsamples within each study plot is 

illustrated in Figure 3. A summary of size class sampling areas and 

designations appears in Table 1. In each size class, vegetation was 

identified, counted, and the percentage of cover contributed by each 

species was visually estimated. Sufficiency of sampling area was 

verified by constructing species area curves (Brower and Zar, 1977) 

for plots that were most floristically rich. Percentage of litter 

cover was visually estimated in each subquadrat. All study plots 

F.I.U. URBAN & REG. DOCS. LIBRARY 
FIGURE 3. Orientation and locations of subsamples within each 

study plot. ( @ = corner of study plot; @ -= corner 

of quadrat). 
TABLE 1. Size class'sampling areas and designations. 

Vegetation Sampling Number 

Size Class Area Dimensions Designation Per Plot 

1 0.25 m' 0.5 m x 0.5 m Subquadrat 16 

(<60 cm) (l.Oml per (Al, A2, A3, 

quadrat ) A4, B1, etc.) 

4 m2/plot 

2 5 m2/quadrat 1mx5m Subplot 4 

(>2m and 20 m2/plot (a, b, c, d) 

<60 cm) 

3 25 m' 5mx5m Quadrat 4 

(>2m) 100 ml/plot (A, C, D) 
were sampled once between December 1977 and February 1978, or in 

December 1979. 

During the wet season (April through October) of 1978 and 1979 

all study plots were examined bimonthly for standing water. When 

water was present, five randomly selected depth measurements were 

recorded per quadrat. Additionally a visual estimate of the 

percentage of area covered by water was recorded for each quadrat. 

Similarity values were calculated using the Sorenson index 

(Mueller-Dombois and Ellenberg, 1974 and Sorensen, 1948) . These 

values were used to generate a similarity matrix and cluster diagram 

(Dixon and Brown, 1979). The cluster analysis of variables used the 

weighted pair-group method (Sneath and Sokal, 1963). Clusters of 

variables were formed based on a measure of similarity between the 

variables; the measure of similarity is the correlation between the . variables. The criterion used to combine variables into clusters or 

clusters into larger clusters were based on the average measure of 

similarity (average linkage ) between the variables or clusters (Dixon 

and Brown, 1979 and Sneath and Sokal, 1973). 

Diversity and evenness were calculated using the Shannon-Weiner 

Index (Brower and Zar, 1977 and Shannon, 1948). Linear regression 

analyses (Sokal and Rohlf, 1969) were used to determine if 

significant relationships existed between the number of exotic 

species or percent exotic species on species richness, evenness and 

diversity. Mann Whitney U tests (siegal, 1956) were used to test the 

significance of environmental, physical and historical factors on 

aspects of community structure. 
Taxonomic nomenclature follows Avery and Loope (1980). 

Designations of exotic species are consistent with Austin (1978). 
RESULTS 

Study Plots 

A general description including a historical synopsis of each 

study plot follows. Table 2 summarizes physical characteristics, 

time of abandonment, and species richness of each study plot. 

Detailed summaries of vegetative cover, species composition, tree 

heights, litter coverage, vegetative density, and hydrological data 

are presented separately. 

Plot 1. Myrica Forest. 

This plot was located just south of a mature pineland. A 

fireroad plowed during the period between 1955 and 1957 separated the 

pineland from the Myrica forest. The canopy cover varied from 80-85% 

and was dominated by Myrica cerifera. Myrsine floridana contributed 

. to the canopy but accounted for less than 1% of the cover. Schinus 

terebinthifolius occurred occasionally in the association, however it 

did not contribute to the canopy in this study plot. 

The canopy height was fairly uniform with a mean of 5.0 m. 

Understory vegetation provided less than 5% cover in both shrub (size 

class 2) and seedling (size class 1) categories. Species composition 

in these size classes consisted of typical pineland species such as 

Guettarda scabra and Forestiera segregata. The vine, Ipomoea indica, 

was also a common understory component. The substrate was rocky and 

covered by a leaf litter from Myrica cerifera. The site was farmed 

after 1952 and was released from farming between 1960 and 1964. 

Prior to farming this site was a mature pineland. No standing water 

was observed. 
TABLE 2. Summary of species richness and hlstorical and physlcal characteristics of each study 

plot. (RL = Rockdale loam). 

Study Total number Approximate date Seasonally 

plot of species of abendonment Soil type Furrows Rock-plowed flooded 

1 19 1965 RL no yes no 

2 2 1 1965 marl no yes yes 

12 toid 1940s marl/ Yes 

organic 

2 5 1973 HL Yes 

mld-late marl yes 

1950s 

yes 

b 13 mid-late marl no no Yes 

1950s 

7 LO =id 19LOs marl no no yes 

8 27 mid 1940s marl Yes no Yes 

196L 

19.40 

mid 19LOs 

prior to 

1910 

1973 

mid 1940s 

mid 1940s 

1940 

prior to 

19LO 

mid 1940s 

mid 1910s 

marl 

marl 

marl/ 

organic 

marl 

marl/ 

organic 

marl/ 

organic 

marl/ 

organic 

marl 

marl 

marl/ 

organic 

marl 
Plot 2. Schinus-Baccharis Subforest. 

This plot was located southeast of the point where Long Pine 

Key Road turns south to the lower missile base. The canopy cover 

ranged from 10 to 20% with a mean height of 2.6 m and was composed 

predominantly of Schinus terebinthifolius. Baccharis halimifdlia 

occurred commonly. The understory was variable with size class two 

providing less than 10% cover. It consisted of hydrophilic species 

such as Pluchea rosea and saplings of Schinus and Baccharis. Size 

class one cover varied from 2 to 65% and consisted mainly of ruderal 

species. Litter cover ranging from 20 to 98% consisted mainly of 

dead or dying herbaceous species and Baccharis from the canop-1 that 

had died and fallen over. The site was initially farmed and 

rockplowed after 1952 and was released during the late 1960's after 

the missile site was constructed in 1965. Standing water was 

seasonally observed. Originally, this site was on the pineland 

prairie ecotone. The substrate reflected this history by having a 

rocky, marl consistency. 

Plot 3. Mixed Psidium Forest. 

This plot was located on the eastern side of the Donut, just 

east of an unpaved farm road that connected Long Pine Key Road and 

Hays Barn Road. The canopy cover ranged from 30 to 75% with Psidium 

guajava dominating. Myrsine floridana was the most abundant species, 

accounting for 75% of all individuals, but less than 15% of the 

canopy cover. The understory cover varied up to 85% and was 

dominated by the exotic, Ardisia solanacea. The site was farmed 
before 1940 and abandoned prior to 1940. It is likely that the 

original vegetation, prior to farming, was prairie. The substrate 

consisted of a furrowed organic soil covered by marl. Occasionally 

the furrows were seasonally flooded. 

Plot 4. Baccharis-Boehmeria Subforest. 

This plot was located south of Long Pine Key Road and west of 

the Hilsenbeck (1976) plots. Baccharis halimifolia was the only 

species in size class three and accounted for all the cover which 

ranged from 2 to 25%. Boehmeria cylindrica and saplings of Schinus 

terebinthifolius were the dominant understory species. The substrate 

was rocky and furrowed. No standing water was observed at any time. 

The site was farmed from the mid-1950's until 1973. The land was 

acquired by the Park Service in 1974. Prior to farming, the site was 

part of the pinelands association. 

Plot 5. Schinus Fore.st. 

This plot was located adjacent to the airstrip at Pine Island. 

The canopy cover ranged between 75 and 80% and was dominated by 

multiple-stemmed Schinus terebinthifolius with a mean height of 4.8 

m. blyrsine floridana was the most abundant species but accounted for - -- 

less than 20% of the cover. The understory vegetation was noticeably 

sparse and composed primarily of Baccharis halimifolia and the vine, 

Parthenocissus quinquefolia. The site flooded seasonally and furrows 

remained from farming the marl substrate. The site was originally 

prairie. Farming started prior to 1940-and the area was acquired by 

the Park Service in 1948 or 1949. It was last farmed in 1950. 
Plot 6. Schinus Forest. 

This plot was located near the airstrip at Pine Island, north 

of Plot 5. It had the same farming history as Plot 5. Community 

structure also resembled Plot 5, however furrows were not evident. 

Plot 7. Ludwigia-Graninoid Association. 

This plot was located north of Plot 3 on the eastern side of 

the Donut, east of an unpaved farm road that connected Long Pine Key 

Road and the Ingraham Highway. There was no canopy cover. Ludwigia 

octovalvis, Andropogon glomeratus and Lythrum lineare were the most 

abundant species and provided 5 to 30% cover in size class two. I 

Herbaceous hydrophillic species such as Bacopa monnieri and Centella 

asiatica formed a cover of up to 95% i'n size class one. The soil was 

marl. Lower areas of the study plot flooded seasonally. This site 

was farmed'and abandoned prior to 1940. Until 1972, this area was 

part of the same community that included Plot 3. In 1972, the 

Resources Management Division of Everglades National Park bulldozed, 

burned and planted Cladium jamaicensis and other species that were 

part of the prefarming prairie community in an attempt to restore the 

original community. 

Plot 8. Mixed Ilex-Myrica Forest. 

This plot was located east of the Donut and south of the 

Everglades National Park entrance station, and adjacent to a rocky - 

prairie. The canopy cover ranged from 50 to 65% and was dominated by 

- Ilex cassine and Myrica cerifera. The tangled shrub understory 

provided up to 75% cover and was dominated by Baccharis 
halimifolia. Common species in size class one, with a mean cover of 

17%, included Toxicodendron radicans and seedlings of Baccharis 

halimifo1,ia and Ilex cassine. The site was farmed and abandoned 

prior to 1940. Prior to farming the site was part of the surrounding 

prairie community. Furrows remained from farming and flooded 

seasonally. The structure and composition of this study area 

resembled a tree island. 

Plot 9. Myrica-Schinus Forest. 

This plat was located southeast of the research center on the 

southern side of Long Pine Key Road. The canopy cover varied to 80% 

and was dominated by Myrica cerifera and Schinus terebinthifolius. 

The understory was sparse providing between 8 and 39% cover. Most 

commonly occurring species were Baccharis glomeruliflora and saplings 

of Schinus terebinthifolius. In size class one cover varied to 50% 

and was dominated by a mix of herbaceous weedy species such as Bidens 

alba and Spermacoce assurgens, and pineland species such as 

Tetrazygia bicolor and.Morinda royoc. The substrate was rocky and 

reflectedthe rockplowed substrate of the original pineland community. 

No standing water or furrows were observed. The site was initially 

farmed after 1952 and released from farming in 1965. In 1979 this 

site was bulldozed, windrowed and burned. A description of the 

vegetation assemblage after 1979 is presented in Loope and Dunevitz 

( 1981) . 
Plot 10. Mixed Myrica-Schinus Forest. 

This plot was located due south of the Research Center and west 

of Plot 9. Farming history and hydroperiod were identical to Plot 9, 

however this study plot was not disturbed in the management practices 

of 1979. Species composition and community structure in Study Plot 

10 resembled Plot 9. However, the canopy was dominated by Schinus 

terebinthifolius and the understory had a cover in size class one 

that varied to 90Z due to the presence of dense Baccharis 

halimifolia. 

Plot 11. Baccharis Glade. 

This plot was located north of the Research Center, on the 

southern side of a fire road plowed between 1955 and 1957. The road 

a 

separated this farmed area from a rocky, transverse glade. The 

sparse canopy cover of Baccharis halimifolia ranged from 0 to 5%. 

Understory vegetation in both size classes was composed of 

hydrophillic, ruderal, graminoid and herbaceous species such as 

Andropogon glomeratus, Eupatorium coelestinum, Phyla nodiflora, and 

Teucrium canadense. The site was rockplowed and farmed between the 

mid-1950's and 1964. Prior to farming the site was part of the rocky 

glade that occupied the area north of the fire road. Standing water 

was present during the wet season. 

Plot 12. Mesic Prairie. 

This plot was located south of the unpaved western portion of 

Long Pine Key Road. There was no canopy. The species composition 

and distribution resembled that of surrounding priarie that had no 
history of farming. Typical prairie species such as Cladium 

jamaicensis, Muhlenbergia filipes, Proserpinaca palustris and 

Rhynchospora microcarpa commonly occurred in the study plot and 

surrounding area. The area flooded seasonally and was never 

rockplowed. The area -was farmed from approximately 194.0 and 

abandoned in 1955. Prior to farming the area was prairie. 

Plot 13. Mixed Successional Forest. 

This plot was located north of the unpaved dump road mid-way 

between the Ingraham Highway and the dump. A well developed canopy 

cover of up to 80% was dominated by Schinus terebinthifolius and Ilex 

cassine. Both the intermediate and small size classes were dominated 

by ~rdisia solanacea and provided up to 95% cover. Leafless Ardisia 

solanacea twigs, probably freeze-damaged, and in some cases over 2 m 

tall, were sprouting from their main stems. Most of the Ardisia 

occurred on ridges between furrows. The site was farmed from the 

late 1930's until 1940. The site was flooded seasonally. 

Plot 14. - Ilex Forest. 

This plot was located on the eastern side of the Ingraham 

Highway south of the unpaved road that leads to the dump. The dense 

canopy provided up to 95% cover with a mean height of 4.5 m. It was 

dominated by Ilex cas-sine with Persea borbonia commonly occurring. 

The intermediate size class cover ranged from 6 to 15% and was 

composed primarily of Baccharis halimifolia and Ludwigia octovalvis 

with saplings of Ilex cassine, Myrsine floridana, and Persea 

borbonia. Size class one was composed of seedlings from the canopy 
and shrub species in addition to hydrophyllics such as Cladium 

jamaicensis, Crinum americanum and Proserpinaca palustris. The 

substrate was marl which lacked litter and organic cover. The plot 

flooded seasonally. The area was farmed and abandoned prior to 1940. 

Before farming, the site was prairie. 

Plot 15. Baccharis Forest. 

This plot was located south of the lower missle base, west of 

an unpaved farm road. The mean canopy cover of 17.5% was provided 

exclusively by Baccharis halimifolia with a relatively uniform height 

of 2.9 m. The sparse intermediate size class cover ranged to 15% and I 

consisted primarily of Baccharis halimifolia saplings and Ludwigia 

octovalvis. Size class one cover varied up to 92% and was dominated 

by a dense mat of Alternanthera philoxeroides. Seasonal flooding of 

the very pfominent furrows occurred. The rockplowed site was farmed 

between 1960 and 1973. Prior to farming the site was occupied by 

prairie. 

Plot 16. Mixed Successional Forest. 

This plot was located north of the dump. The mean canopy cover 

of 25% with a mean height of 4.8 m was dominated by Persea borbonia. 

Baccharis halimifolia, Ilex cassine, and Myrica cerifera also 

contributed to the canopy cover. Baccharis halimifolia, Ardisia 

solanacea, and juvenile - Ilex cassine were the major contributors to 

the sparse cover of 13 - 23% in size class two and 0.5 to 10% in size 

class one. The soil was not furrowed and had an organic layer over a 

marl substrate. The site flooded seasonally. Plot 16 was assumed to 

have the same farming history as Plot 13. 
Plot 17. Mixed Successional Forest. 

This plot was located south of the road that leads to the dump 

and southeast of the dump. The canopy varied up to 90% cover with a 

mean height of 6.1 m and consisted of seven species including Schinus 

terebinthifolius. Both understory size classes had a sparse cover 

consisting primarily of seedlings and saplings of canopy species and 

other common understory species such as Psychotriz sulzneri and 

Thelypteris kunthii. The substrate was prominently furrowed and the 

site flooded seasonally. Plot 17 had the same farming history as 

Plot 13. 

Plot 18. Mesic Prairie. 

This plot was located south of the unpaved portion of the Long 

Pine Key Road, east of Plot 12. There was no overstory. Prominent 

furrowing distinguished this farmed area. Baccharis halimifolia, 

which commonly occupied the ridges between furrows, and were less 

than 2 m tall, provided up to 28% cover in the intermediate size 

class. Typical prairie species such as Cladium jamaicensis, Crinum 

americanum, and Panicum hemitomum were intermixed with hydrophillic 

ruderal species such as Bacopa monnieri, Phyla nodiflora, and 

Spermacoce prostrata and provided up to 80% cover. The site 

seasonally flooded and had the same farming history as Plot 12. 

Plot 19. Mixed Furrowed Prairie. 

This plot was located south of the point where the Ingraham 

Highway turns westward. There were eight individuals greater than 2 

m tall which provided a mean cover of less than 42. The most 
striking feature bf the vegetation at this plot was its localized 

distribution on the ridges between the shallow furrows. Exposed marl 

occurred in the furrows. The vegetative conposition reflected the 

proximity to Taylor Slough, and the scattered tree islands. Baccharis 

halimifolia occurred in all size classes. Andropogon glomeratus, 

Cladium jamaicensis, Ludwigia spp., Proserpinaca palustris, and 

Rhynchospora inundata were the most abundant species. Occasional 

immature Magnolia virginiana, Myrica cerifera,. Myrsine floridana, 

Salix caroliniana and Taxodium distichum characterized the site. The 

seasonally flooded site was farmed for a very short period prior to I 

1940. Prior to farming the site was prairie. 

Plot 20. Mixed Successional Forest. 

This plot was located northeast of Donut Lake. The canopy a 

cover varoed up to 90% with a mean height of 3.0 m and was provided 

by five species with Myrica cerifera and Persea borbonia dominating. 

Ampelopsis arborea, Parthenocissus quinquefolia, and Toxicodendron 

radicans entangled into the understory and canopy contributed to the 

cover in all size classes. Baccharis.halimifolia, PIyrica cerifern 

and Persea borbonia occurred in all size classes. The intermediate 

size class, dominated by Baccharis halimifolia, formed a tangled 

cover providing up to 26% cover. Size class one with a cover ranging 

between 3 and 50% was dominated by seedlings of species in other size 

classes and hydrophillic species including Hydrocotyle umbellata and 

Ptilmnium capillaceum. The site flooded seasonally and was farmed 

and released prior to 1940. Before farming, the site was prairie. 
Plot 21. Early Successional Glade. 

This plot was located south of Hays Barn Road and south of the 

Hilsenbeck (1976) study plots. There was no vegetative cover in size 

class 2 or size class 3. Herbaceous cover in size class 1 ranging 

between 30 and 90% consisted of prairie and ruderal species. Some of 

the most common species were Baccharis halimifolia; Dichromena 

colorata, Eupatorium capillifolium, E. coelestinum, Hydrocotyle 

umbellata, Ludwigia microcarpa, Lythrum lineare and Spermacoce 

prostrata. The site had a marl substrate which flooded seasonally. 

It was bulldozed in 1978. Prior to this, it was occupied by a 

successional forest. The area was farmed prior to 1940 and abandoned 

in the mid-1950's. The site was rockplowed. Prior to farming the 

site was occupied by prairie. 

Species Composition 

Species composition in each study plot is presented in Appendix 

1. A total of 139 species were recorded in this study from all 21 

study plots. The greatest number of species occurred in size class 

one, in all plots. The percentage of exotic species varied between 0 

and 91%. 

Only 11 species formed the canopy in all study plots, with no 

more than seven in any one study plot. When a species occurred in 

the canopy, it was almost always found as saplings or seedlings. 

There were three plots whose canopy was provided only by Baccharis 

halimifolia. When this occurred, seedlings or saplings of other 

canopy species also occurred. Two exotic canopy species were 
Schinus and Psidium. They occurred in 50% of all plots with a canopy 

and were one of the dominant species when present. 

Figure 4 illustrates the frequency distribution of all species 

found in the 21 study plots. Many of the species encountered were 

relatively rare to uncommon. Of the 139 species encountered, 44 

occurred in only one study plot, 22 occurred in only two study plots, 

and 20 occurred in only three study plots. Approximately 25% of the 

species occurred in more than half the study plots. 

Table 3 presents the nine species that were found in over half 

of the 21 study plots. Baccharis halimif-, Myrica cerifera, 

Myrsine flosidana, and Schinus terebinthifolius all occurred in size 

class three. Schinus was the only exotic species that occurred in 

more than 50% of the study plots. The other eight species that 

commonly occurred were in size class one and two and were herbaceous 

. perennials that are able to persist under variable conditions. These 

species usually appear in early succession and persist. 

Study Plot Similarities 

Table 4 shows the similarity index matrix for all study plots. 

This is based upon species presence and does not take into account 

relative abundances. Sorensen coefficient of similarity values ranged 

from 0 to 71%. 

A common practice in evaluating similarity indices is to divide 

the range of the indices into equal intervals (Bloom 1981). Since the 

Sorensen index ranges from 0 to 100, five distinct similarities can 

be generated (very low, low, moderate, high and very high) based on 

20% intervals. Using this technique, 128 values in the matrix were 
Number of Plots 

FIGURE 4. The number of species that occurred in one or more 

study plots. 
TABLE 3. Species which occurred in more than 50% of all 

study plots. ( (E) = exotic species). 

Species 

Percent Occurrence 

in Plots 

Andropogon glomeratus 62 

Baccharis halimifolia 8 6 

Boehmeria cylindrica var. drummondiana 71 

Eupatorium coelestinum 52 

Myrica cerifera 71 

Myrsine floridana 52 

Parthenocissus quinquefolia 52 

Schinus terebinthif olius (E) 57 

Thelypteris kunthii 62 
TABLE 4. Study plot similarities based on the Sorensen Coefficient of Similarity. (The matrix 

is symmetrical above and below the diagonal). 

Plot No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 I9 20 21 
very low, 67 values were low, 14 values were moderate and one value 

was high. The highest similarity (71) occurred between Plots 5 and 

6. Plots 3 and 11 and 6 and 11 showed no similarity. Plot 15 

showed the least similarity with all other plots, while plots 2, 7, 

11, and 19 showed only low similarities with other plots. Plot 16 

showed the most similarity with the greatest number of plots, while 

plots 5, 6, 8, and 17 exhibited relatively strong similarities with 

several plots. 

In order to further characterize the similarities between study 

plots, a cluster analysis was performed. Figure 5 shows the resulting 

dendrogram: All study plots clustered above the 50% similarity 

level. Four cluster groups composed of at least three study plots 

per group were identified in the analysis. These are designated in 

Figure 5 as cluster groups A, B, C, and D. Cluster group A is 

characterized by study plots that were dominated mostly by a canopy 

cover varying to 90%, containing relatively few canopy species (no 

more than three), occurring on a marl substrate, flooding during the 

wet season, and abandoned in the 1940's and 1950's. Study plots in 

cluster group B contained a relatively low to moderate number of 

species with a high percentage (up to 46% or 7 species) providing a 

canopy cover of up to 90%. These were abandoned in 1965 and the mid1940's. Group C study plots are characterized by moderate numbers of 

species with 10% or less producing a canopy cover of 25% or less, and 

abandoned in the 1960's and 1970's. Group D is characterized by 

study plots with a moderate to high number of species, no history of 

rockplowing, abandonment prior to or during the 19401s. With the 
I - 

'2 

'a. 
e-:ception of Plot 14, canopy ccver is less than 7% and less than 12% 

of all species are present in slze class three. 

Study plots 1, 8, 9, 15, and 20 did not belong to any cluster 

group. Plots 1 and 9 had similar compositions in that typical 

pineland species, such as Tetrazygia bicolor and Morinda royoc, 

occurred. Although the vertical structure of Plot 8 was similar to 

plots in cluster B, it contained species that did not occur in any of 

the cluster B plots. Unlike characteristics.of any of the groups, 

Plot 15 had an overstory composed entirely of Baccharis halimifolia 

and an understory of hydrophillic ruderal species. Study plot 20 was 

most similar to cluster D but it contained relatively few species. 

Canopy Cover and Vegetation Size Class 

Figures 6A-6D present the mean and range of percent cover for 

each vegetation. size class in each study plot. Species that 

contributed to the cover in each size class are listed in Appendix 1. 

For all study plots, size class one cover varied from 0 to 95%, size 

class two cover varied from 1 to 85%, and size class three cover 

varied from 0 to 95%. 

Abundance, Diversity and Evenness 

Table 5 presents the number of individual plants in each size 

class for all plots. Size class one had the greatest number of 

individuals in all study plots, although in many plots these numbers 

are probably affected by seasonal changes. 

Generally, those plots that lacked a canopy and had relatively 

large numbers of individuals were concentrated in size class one. 
FIGURE 6A. Mean and range of percent cover for each vegetation 

size class in study plots 1-6. 

F.I. U. URBAN & REG. DOCS. LIBRARY 
Percent Cover Percent Cover 
FIGURE 6C. Mean and range of percent cover for each vegetation 

size class in study plots 13-18. 

TABLE 5. Total numbers of individual plants in each size class in 

each study plot. 

Size Class (Height) 

Size Class 1 Size Class 2 Size Class 3 

Plot No. Small (<60cm) Intermediate (>60cm <2m) Tall (>2m) 
Plots 1 and 6 had notably small numbers of individuals. The small 

numbers of individuals in'size class three plots reflects either a 

sparse cover or a few well-developed individuals that formed a dense 

cover. 

After determining that differences between subplots were 

minimal, diversity (HI) and evenness (e) values were calculated for 

all study plots. These results are presented in Table 6. Diversity 

values were low for all assemblages. Both the richness and evenness 

component of diversity contributed to these low values. Those plots 

with the lowest and highest evenness also had the lowest and highest 

diversity values. Study plots 13 and 15 had the lowest diversity and 

evenness values. In both cases, the small number of species and the 

small number of individuals of rare species within the plot 

contributed. to the low diversity values. Plots 12 and 18 had the 

highest evenness and diversity values. Both plots had a relatively 

high number of species that were relatively evenly distributed. 

Those plots with the lowest diversity values had a canopy, and those 

with the highest diversity values had no canopy. Table 6 also 

presents the percentage of exotic species found in each study plot. 

This is expressed two ways. Percent exotics one (% Exotics 1) is the 

percentage of the number of exotic species compared to the total 

number of species present. Percent exotics two (% Exotics 2) is the 

number of individuals of exotic species compared to the total number 

of individuals of all species. The number of exotic species always 

represented less than 34% of all species but in plots 2, 3, 13 and 15 

more than 50% of the individuals were exotic. In addition to having 
TABLE 6. Diversity, evenness, and % exotics in each study 

plot . 

Diversity Evenness % % 

Plot H ' e Exotics 1 Exotics 2 

H' Shannon Wiener diversity index based on abundance. 

e Evenness index, from Shannon Wiener index. 

% Exotics 1 is the percentage of the number of exotic 

species compared to the total number of species present. 

% Exotics 2 is the number of individuals of exotic species 

compared to the total number of individuals of all 

species. 
a high number of exotics in these plots, exotics provided the 

majority of the cover. In study plot 2 Schinus terebinthifolius 

dominated the canopy while in plot 3 Schinus terebinthifolius, 

Ardisia solanacea and Psidium guajava provided the majority of the 

cover. Plot 13 had Ardisia solanacea and Schinus terebinthifolius as 

the dominant canopy species while in plot 15 Alternanthera 

philoxeroides provided most of the cover. Plots 13 and 15 had 

dominant exotic species and also exhibited the two lowest diversity 

and evenness values of all study plots. 

Canopy Height and Litter Cover 

Tree height data for all study plots are presented in Table 7. 

As would be expected the tallest trees usually occurred in study 

plots that have been abandoned for longer periods of time. Tree 

heights ranged from 2.0 m to 9.4 m. Of the 17 study plots with . trees, five had mean tree heights less than 3.0 m, four had mean tree 

heights between 3.0 m and 4.0 m, five had mean tree heights between 

4.0 m and 5.0 m, two had mean tree heights between 5.0 m and 6.0 m, 

and one plot had a mean tree height greater than 6 m. 

Percent litter cover, which includes dead plant material, is 

also presented for all study plots in Table 7. The mean percentages 

of litter cover varied from 11.8% to 97.9%. 

Hydrolo~y 

Results of hydrological censuses are reported in Table 8. 

Study plots 1, 4, 9, and 10 were not flooded at any time. These 

study plots were areas that were occupied by pineland before farming. 
TABLE 7. Mean tree height and percentage litter cover ior izh s-: 

plot. 

Tree Height (m) Litter Cover --- b) 

Plot No. n Mean - t S.D. (range) Mean + S.D. (range) - 
TABLE 8. Summary of hydrological data during the seven month 

wet season from April to October during 1978 and 1979. 

% Time flooded % Area flooded Water depth 

Plot No. during wet season Mean - + S.D. (mm) Mean - + S .D. 

1 0 -- -- 2 27 60.2 + 45.9 65.6 + 51.5 

3 4 22.5 '7 - 9.6 45.7 5 12.7 

4 0 -- - - 

5 8 23.1 + 14.9 41 .7 + 28.1 

6 27 53.4 i 40.4 38.1 + 38.0 

7 42 69.1 + 41.7 85.4 ' 71.8 

8 27 46.L -20.7 73.2 2 40.3 

9 0 -- - - 

10 0 -- -- 

11 31 87.4 + 32.4 108.3 + 62.7 

12 I 5 1 84.2 2 76.7 57.4 z 41 -5 

13 3 8 63.0 + 42.2 77.0 + 61.9 

14 6 5 43.3 z 34.7 66.7 81.6 

15 3 8 50.3 2 18.5 86.9 83.1 

16 3 8 69.9 2 41.6 81.0 55.2 * / 42 47.0 2 38.5 61.5 T 48.0 

18 46 59.1 + 34.3 60.2 45.1 

19 69 85.1 + 17.9 83.1 7 44.7 

20 15 41.1 41.2 62.8 T 63.6 

2 1 46 89.0 z25.7 71.7 z 33.7 
The percentages of time during the wet season that each study plot 

was flooded was calculated based on bimonthly visits during the seven 

month wet season from April to October. Plot 19, which was inundated 

for more of the wet season than other plots, was covered with water 

69% of the wet season. The area covered by standing water varied with 

water depth and local topography. When water depth was relatively 

high, 100% of the area of some plots were inundated. Water depth was 

greatest (108.3 mm) in Plot 11. 

Community Structure, Agricultural History, Soil Type and Hydrology 

Results of Mann Whitney U tests showing the relationship of 

rockplowing, furrowing, soil type, standing water, time of 

abandonment and shade (canopy/no canopy) on aspects of community 

structure are summarized in Table 9. With the exception of canopy 

absence there were no significant relationships (p > 0.05) of these 

parameters on the nuuber of species, diversity (HI ) , evenness (e) or 

percentage of exotics. Figure 7 illustrates that species richness is 

greater when no canopy exists (p < 0.01). 

The Effects of Exotic Species 

The effects of the number of exotic species and the number of 

exotic individuals on total species richness, evenness (e) and 

diversity (HI) in all study plots is presented in Table 10. The 

number (presence or absence) of exotic species does not affect 

richness, diversity, or evenness (p > 0.05) . Species richness 

decreases as the percentage of exotics, calculated as the number of 

exotics divided by the total number of species, increases (p < 0.05) 
TABLE 9. Results of Mann Whitney U tests comparing study plots for 

rockplowing/nonrockplowing , rockdale loam/marl , furrows/no 

furrows, standing water/no standing water, early (1940, 

1950) /late (1960, 1970) abandonment, and canopy/na canopy. 

Standing Time of ~anopy/~o 

Rockplow Furrows Soil Type Water Abandonment Canopy 

Species 

Richness n. s. n.s. n.s. n.s. n.s. ,Y 

Diversity n. s . n.s. n.s. n.s. n.s. * 

(H') 

Evenness n.s. n.s. n.s. n.s. n.s. n.s. 

(e) 

% Exotics 1 n. s. n.s. n.s. n.s. n.s. n.s. 

% Exotics 2 n.s. n.s. n.s. n.s. n. s. * 

* .01 <p < .05 

n.s. = no significant difference. 

% Exotics 1 is the percentage of the number of exotic species compared 

to the tot51 number of species present. 

% Exotics 2 is the number of individuals of exotic species compared to 

the total number of individuals of all species. 
FIGURE 7. The relationship between canopy presence or absence and 

the number of species. 
TABLE 10. Summary of linear regression analyses. 

Significance 

Y level r 

Number of exotic 

species 

Number of exotic 

species 

Number of exotic 

species 

% exotics 1 

% exotics 1 I 

% exotics 1 

% exotics 2 

% exotics 2 

% exotics 2. 

Richness 

Evenness 

Diversity 

Richness 

Evenness 

Diversity 

Richness 

Evenness 

Diversity 

n.s. = no significant difference (p < 0.05). 

% exotics 1 is the percentage of the number of exotic 

species compared to the total number of species present. 

% exotics 2 is the number of individuals of exotic species 

compared to the total number of individuals of all 

species. 
(Fig. 8). Species richness, evenness, and diversity decrease as % 

Exotics 2 increases (Figs. 9, 10, 11 ) . 
FIGURE 8. Linear regression of percentage of exotic species 

against total number of species (df = 19). 

- 

ma, 

0 d 

. . 0 0 

I w 

v II - - 0 

a L r) + 

K 

0 

w 

0 

I 

* 

w 

A3 

P) 

d 

N 

13 - 

4 

4 

4 4 

4 

I I I I - r) 

0 0 0 0 0 V) w P) N - 

( ssa"'43!tj) 

S3133dS 30 U38WnN 1V101 
TOTAL NUMBER OF SPECIES 

(Richness ) 
FIGURE 10. Linear regression of percentage of exotic individuals 

against species evenness (df = 19). 
FIGURE 11. Linear regression of percentage of exotic individuals 

against species diversity (df = 19). 
ACKNOWLEDGEMENTS 

I am particularly grateful to my major advisor, Dr. D. F. Austin, whose 

persistent guidance and cooperation allowed me to complete my thesis. I am 

grateful to Drs. R. Adams, T. Sturrock and M. Boss for their advice and 

critical input. 

I am thankful to Dr. L. Loope and Dr. G. Hendrix of the South Florida 

Research Center, Everglades National Park, for providing me the research 

position that gave me the opportunity to perform the study. I appreciate 

the field assistance from N. Urban, L. McNabb, R. Bruckbauer, and R. 

Russell. G. Avery provided invaluable assistance in plant identification. 

I am indebted to M. McMahon, Dr. F. Mazzotti, and N. Gillies for their 

numerous suggestions and assistance. 

Special thanks is due to J. Cowart of Environmental Science and 

. Engineering, Inc., and to Metcalf and Eddy, Inc., for allowing the 

flexibility in my employment status to complete my thesis. 

I am indebted to B. Bohnsack for typing the manuscript and A. Lewis for 

graphics preparation. 

I am thankful to my fellow graduate studies, J. Jones and C. Nauman. 
nearly pure stands with Myrica, Ilex, and Persea slowly colonizing. 

In general, findings of this study confirm these predicted trends. 

The vegetation in the Hole-in-the-Donut provides the 

opportunity to evaluate and predict successional trends. The present 

mosaic in the study site with the exception of the western portion of 

the Donut and along the Old Ingraham Highway does not resemble the 

pre-farming vegetation mosaic which was dominated by prairie. The 

existing communities on abandoned farmland in the Donut consist of a 

mixture of successional assemblages including early successional 

stages (less than ten years after abandonment), which have been 

thoroughly described by Hilsenbeck (1976) and Loope and Dunevitz 

(1981), as well as older successional associations. These older 

successional associations were most intensively inventoried in the 

present study. Study sites considered as early successional 

assemblages in the present study are typified as Baccharis-Boehneria 

Subforest and Baccharis Forest. Study sites considered as older 

successional assemblages are typified as Myrica Forest, SchinusBaccharis Subforest, Mixed Psidium Forest, Schinus Forest, Ludwigia- - 

Graminoid Association, Ilex-Myrica Forest, Myrica-Schinus Forest, 

Baccharis Glade, Mesic Prairie, Mixed Successional Forest, - Ilex 

Forest, Mixed Furrowed Prairie, and Early Successional Glade. Each 

of these associations has been charzcterized in the study plot 

descriptions. 

The vegetation associations described as successional forest 

and represented by groups A and B in the cluster analysis shown in 

Figure 5 are either dominated by a mix of canopy species or by one to 
two species. Forest dominance by species does not appear to be due 

to a result of differences in farming history, hydrological 

differences or substrate variations, but most likely seed storage or 

proximity to a seed source. The presence of dominant canopy species 

in each size class (Table 3) in the study plots indicates that the 

.successional forests are maintaining themselves. These successional 

forest assemblages, referred to by Alexander and Crook (1973), Ewe1 

-- et al. (1982), and Loope and Dunevitz (1981) are likely final stages 

in secondary succession. 

The two associations described as subforest and represented as 

group C in the cluster analysis shown in Figure 5 occur on sites that 

were abandoned in the 1960's and 1970's. Although other study sites 

abandoned at about the same time support forest associations, the 

species complement of Plot 2 (Schinus-Baccharis Subforest) and Plot 4 . (Baccharis-Boehmeria Subforest) of group C suggest that forest 

associations also will eventually dominate these sites. The reasons 

for the more retarded ecosystem development at these sites is not 

apparent. Based on species composition, Baccharis Glade, like the 

subforest associations, seem to represent an intermediate step in the 

successional process. This association however, more closely 

resembles the original prairie than the subforests that occupy former 

prairie and pineland. 

The study plots typified as Mesic Prairie, Mixed Furrowed 

Prairie and Early Successional Glade represented by cluster group D 

(Fig. 5) resemble the pre-farming prairie more than other study 

plots. The Mesic Prairie and Mixed Furrowed Prairie have been 
undisturbed since the 1940's. The Early Successional Glade, 

previously occupied by successional forest, but bulldozed in the ' 

early 19701s, has a species complement resembling plots that have 

been relatively undisturbed. The species composition and 

distribution in Plot 7 typified as Ludwigia-Graminoid Association 

most closely resembles-a sere described by Egler (1952) which he 

suggests nay revert to a sawgrass prairie as a result of fire. The 

management treatment used on this relatively small area has altered 

the successional pattern. The untreated adjacent area where Plot 3 

is located remains occupied by forest. 

The presence of Baccharis spp. or Ludwigia octovalvis in all 

study plots that have no canopy suggests that future development into 

successional forest is likely. Potential exceptions are study Plots 

12 (Mesic Prairie) and 18 (Mesic Prairie) which both resemble the 

original prairie community. The presence of Baccharis which is not 

routinely common in the surrounding prairie suggests that farming 

disturbance has initiated some subsequent succession. These plots 

V, 

have been abandoned since 1940 and. the substrate has not 'been 

subsequently aerated or disturbed. It is understandable, therefore, 

that the rate of succession in these plots is very slow and edaphic 

conditions as well as relative distance to successional forest seed 

sources may inhibit .. further succession. Other plots that were 

abandoned in the same' time period but were proximal to seed sources 

of successional species eventually became dominated by successional 

forest. 
Before farming, the vegetation of the Donut was 80% prairie, 7% 

glade, 2% ponds, 9% slash pine community (Pinus elliotti var. densa) 

with the rest either hammock or bayhead (Hilsenbeck, 1976; Resources 

Management, 1976) . 

The community structure of the successional vegetation studied 

exhibits a different species complement than the surrounding 

communities or the communities which originally occupied the area. 

Olmsted, Loope and Rintz (1980) report that Muhlenbergia prairies in 

the Taylor Slough area adjacent tolthe Donut are composed of nearly 

100 plant species. Long (1974) reports 172 species occupy wet 

prairies in southern Florida. Loope -- et al. (1979) report that the 

pineland shrub understory in the Long Pine Key area is composed of 30 

to 40 species and an herbaceous understory of 100 species. Olmsted, 

Loope and Hilsenbeck (1980) report 200 vascular plant species in . hammocks nearly half of which are trees and shrubs. A preliminary 

checklist of vascular plants in the Donut (Krauss 1979) includes over 

260 species. These include species that commonly occur in the 

surrounding pinelands, hammocks, prairies, and glades. Although the 

species composition in all the successional study plots totalled 139, 

only eleven species occur in the canopy of all plots. Fifty-one 

species occur in the intermediate size class, many being primarily 

herbaceous rather than shrubs. 

In the successional assemblages inventoried, where canopy 

development has occurred, species richness is low. The time required 

for forest development is not.necessarily related to the time of 

agricultural abandonment. Successional assemblages with vertical 
stratification that includes a canopy have lower species richness. 

Loope and Dunevitz (1981) report a tentative increase in shrubby 

vegetation in areas abandoned between 1973 and. 1975. They also 

report an increase of Schinus five years after abandonment with a 

nearly twenty-fold increase between 1977 and 1978. Assuming that 

this is representative o.f all past farming, non-forested assemblages 

in the Donut, the area dominated by successional forest will 

gradually increase while species richness will decrease. 

The ecology of Schinus terebinthifolius and its role in the 

Donut has been studied by Ewe1 -- et al. (1982). Although Schinus is 

the most abundant exotic species in the Donut, the combined effect of 

all exotic species has been evaluated. As the frequency of exotics 

increase, species richness, evenness, and diversity decreases. 

Schinus was first noted in the Royal Palm area in Everglades 

National Park in the 1940's (Bancroft, 1973). It became a component 

of post-farming successional forests. Because of the extremely 

aggressive nature of Schinus and its established presence in the 

Donut, areas that are now dominzted by shrubs and subforest 

assemblages will probably become dominated by Schinus forests similar 

to Plots 5 and 6 (Schinus ore st). The only sites that will become 

mixed successional forests are probably those in which other 

successional forest species establish before Schinus. 

Since the release from farming, successional forest and the 

seres leading to it have become new components in the vegetational 

history of the Donut. In fact, successional forest is a relatively 

new community in southern Florida. Prior to the introduction of 
exotics, literature describing southern Florida communities (Davis, 

1943; Egler, 1952; Craighead, 1971) did not mention this type of 

successional association. The results of this research together with 

the findings of Ewe1 -- et al. (l982), Hilsenbeck (1976), and Loope and 

Dunevitz (1981) indicate that the defined successional assemblages 

should be considered a community, together with other historical 

communities such as hammocks., pinelands, and prairies, in the 

southern Florida ecosystem. This community is most appropriately 

termed Successional Forest. It is characterized by a well-developed 

canopy with low species richness and variable composition that is 

self -maintaihing. 

The specific composition and environmental qualities of a site 

are not the defining characters. Successional Forests occur with 

varying disturbance history. In the Donut, the Successional Forest 

canopies are composed of a mix or dominance by the following species: 

Schinus terebinthifolius, Psidium quava, Persea borbonia, Myrsine 

quianensis, Ilex cassine, Baccharis halimifolia, and Ilyrica cerifera. 

Outside of Everglades National Park, Successional Forest may be 

dominated by exotic or native species including: Melaleuca 

quinquenervia, Casuarina equisetifolia, Laguncularia racemosa, and 

Albizzia lebbeck. 
CONCLUSIONS 

1. The findings of this study generally confirm the 

successional trends predicted by Hilsenbeck (1976) and 

Loope and Dunevitz (1981). 

2. With limited exceptions, post-farming vegetation patterns 

do not resemble the prefarning vegetation mosaic. 

3. Vegetation dominance does not appear to be a result of 

differences in farming history, hydroperiod or substrate variation. 

4 If present community relationships persist, as the 

frequency of exotics increase, species richness, evenness and 

diversity will decrease. 

5. Successional forest is a relatively new community in 

southern Florida and should be considered in a context 

along with communities such as hammocks, pinelands and 

prairies. 

6. It is likely that the area occupied by successional 

forest will gradually increase while species richness 

will gradually decrease. 

7. Successional forests are likely final stages in secondary 

succession after farming. 
ACKNOWLEDGEMENTS 

I am particularly grateful to my major advisor, Dr. D. F. Austin, whose 

persistent guidance and cooperation allowed me to complete my thesis. I am 

grateful to Drs. R. Adams, T. Sturrock and M. Boss for their advice and 

critical input. 

I am thankful to Dr. L. Loope and Dr. G. Hendrix of the South Florida 

Research Center, Everglades National Park, for providing me the research 

position that gave me the opportunity to perform the study. I appreciate 

the field assistance from N. Urban, L. McNabb, R. Bruckbauer, and R. 

Russell. G. Avery provided invaluable assistance in plant identification. 

I am indebted to M. McMahon, Dr. F. Mazzotti, and N. Gillies for their 

numerous suggestions and assistance. 

Special thanks is due to J. Cowart of Environmental Science and 

Engineering, Inc., and to Metcalf and Eddy, Inc., for allowing the 

flexibility in my employment status to complete my thesis. 

I am indebted to B. Bohnsack for typing the manuscript and A. Lewis for 

graphics preparation. 

I am thankful to my fellow graduate studies, J. Jones and C. Nauman. 
LITERATURE CITED 

Alexander, T.R. and A.G. Crook. 1973. Recent and long-term 

vegetational changes and patterns in South Florida, Part I. 

Preliminary report for N . P . S . (EVER-N-51) . 215 pp . 

Austin, D'.F. 1978. Exotic plants and their effects in southeastern 

Florida. Environ. Conserv. 5 (1) :25-34. 

Avery, G.N. and L.L. Loope. 1980. Plants of Everglades National 

Park: A preliminary checklist of vascular plants. South Florida 

Research Center Report T-558. 39 pp. 

Bancroft, L. 1973. Hole-in-the-Donut, farmland reclamation program. 

Everglades National Park Resources Management Internal 

Memorandum. 

Bloom, S.A. 1981. Similarity indices in community studies: 

Potential pitfalls. Marine Ecology-Progress Series 5:125-128. 

Brower, J.E. and J.H. Zar. 1977. Field and laboratory methods for 

general ecology. Wm. C. Brown Co., Dubuque, Iowa. 194 pp. 

Carter, L.J. 1974. The Florida Experience. The Johns Hopkins 

University Press. 355 pp. 

Craighead, F.C., Sr. 1971. The Trees of South Florida. Univ. of 

Miami Press, Coral Gables, F1. 212 pp. 

Davis, J.H., Jr. 1943. The natural features of southern Florida. 

Florida Geological Survey Bulletin 25. 311 pp. 

Dixon, W.J. and M.B. Brown. 1979. BMDP-79, Biomedical Computer 

Programs, P-Series. University of California Press, Berkeley. 880 

PP 
Egler, F.E. 1952. Southeast saline Everglades, Florida and its 

management. Vegetatio 3:213-265. 

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34 
APPENDIX 1. Species composition in each study plot. Nomenclature is in accord with Avery and Loope 

(1980). (E = exotic species). 

SPECIES 

PRESENCE IN SIZE CLASS 

I 2 3 SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 

PLOT 1 

Ardisia escallonioides 

Baccharis halimifolia 

Boehmeria cylindrica 

Bumelia salicifolia 

Forestiera segregata 

var. pinetorum 

Guettarda scabra 

Ilex cassine 

Ipomoea indica 

Metopium toxiferum 

Norinda royoc 

Myrica cerifera 

blyrsine f loridana 

Nectandra coriacea 

Parthenocissus quinquefolia 

Passiflora suberosa 

Psidium longipes 

Psychotria sulzneri 

Tetrazygia bicolor 

Vitis munsoniana R 

Total 13 9 2 

PLOT 2 

Andropogon glomeratus 

Baccharis halimifolia 

Boehmeria cylindrica 

Cyperus ligularis 

Galium obtusum 

var. floridanum 

Hydrocotyle umbellata 

Ludwigia microcarpa 

Ludwigia octovalvis ssp. octovalvis it 7Y 

Macroptilium lathyroides E +e 

Mikania scandens 3 

Parthenocissus quinquefolia it 

Phyla nodiflora E " 

Pluchea rosea r 

Sarcostemma clausum 

Schinus terebinthif olius - 

Setaria geniculata K 

Solidago sempervirens var. mexicana 

Sperniacoce assurgens ?C 

Verbena scabra it 

Vicia acutifolia 

Vigna luteola 

?i 

+C 

Total 19 7 2 
APPENDIX 1. 

SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 SPECIES 

a PRESENCE IN SIZE CLASS 

1 2 3 

PLOT 3 

Acrostichum danaeifolium 

Ardisia solanacea 

Hypericum hypericoides 

var. hypericoides 

Myrica cerifera 

Myrsine floridana 

'Persea borbonia .,- Boehmeria cylindrica 

Schinus terebinthifolius 

Thelypteris kunthii 

Trismeria trifoliata 

PLOT 5 

Acrostichum danaeifolium 

Ardisia solanacea 

Baccharis halimifolia 

var. drummondiana 

Boehmeria cylindrica 

- Ilex cassine 

Myrica cerifera 

Myrsine floridana 

Parthenocissus quinquefolia 

Total 7 8 3 

PLOT 4 

Ambrosia artemisiifolia. 

Ampelopsis arborea 

Andropogon glomeratus 

Baccharis halimifolia 

Bidens - alba 

Boehmeria cylindrica 

Chamaesyce hyssopifolia 

Commelina diffusa 

Diodia virginiana 

Eupatorium capillifolium 

Eupatorium coelestinum 

Galium obtusum var. floridanum 

Ludwigia octovalvis 

ssp. octovalvis 

Lythrum lineare 

Melothria pendula 

Mikania scandens 

Parthenocissus quinquefolia 

Psidium longipes 

Schinus terebinthifolius 

-- Sida acuta 

Spermacoce assurEens 

Spermacoce prostrata 

Thelypteris kunthii 
APPENDIX 1. 

SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 

PLOT 5 (Cont. ) 

Persea borbonia 

Psidium gua j ava 

Psychotria nervosa 

Cissus sicyoides 

Psidium guaj ava 

Bidens alba 

m ~sychotria sulzneri 36 

UI Schinus terebinthifolius E * 

Thelypteris kunthii 3c +t 

Toxicodendron radicans * it 

Total 12 9 2 

PLOT 7 

Ammannia latifolia 

Andropogon glomeratus 

Aster dumosus 

Aster tenuifolius 

Baccharis halimif olia 

&copa monnieri 

Boehmeria cylindrica 

Centella asiatica 

PLOT 4 (Cont. ) 

Vigna luteola 

Vitis aestivalis 

PLOT 6 

Ardisia solanacea 

Boehmeria cylindrica 

Hydrocotyle umbellata 

- Ilex cassine 

Myrica cerifera 

~yrsine floridana 

Parthenocissus quinquefolia 

Persea borbonia 

Psidium guajava 

Psychotria sulzneri 

Schinus terebinthifolius 

Thelypteris kunthii 

Toxicodendron radicans 

PLOT 8 

Acrostichum danaeifolium 

Ampelopsis arborea 

* 

* 

Total 24 12 1 

E * * ic 

36 

* 

* 

* 3f 

* 

* 

E +c * * 

3C 

E% * % 

?I * 

?f 

Total 10 8 2 
APPENDIX 1. 

SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 

PLOT 7 (Cont. ) PLOT 8 (Cont.) 

Cynoctonum mitreola 

Cyperus ligularis 

Cyperus surinamensis 

Dichromena colorata 

Diodia virginiana 

Eleocharis caribaea 

m Erigeron quercifolius m Eupatorium coelestinum 

Galium obtusum var. floridanum * 

Hydrocotyle umbellata +t 

Juncus megacephalus 

Ludwigia alata 

Ludwigia microcarpa 

Ludwigia octovalvis 

ssp. octovalvis it * 

Ludwigia repens 

Lythrum lineare 

Mikania scandens 

Muhlenbergia filipes 

Panicum bartowense 

Phyla nodiflora 

Pluchea odorata 

Proserpinaca palusris 

var. palustris 

Rhynchosia minima 

Setaria geniculata 

Baccharis halimifolia 

Boehmeria cylindrica 

Crinum americanum 

Eugenia axillaris 

Eupatorium coelestinum 

Habenaria odontopetala 

Hypericum hypericoides 

var. hypericoides 

Hyptis alata var. stenophylla 

- Ilex cassine 

Kosteletzya virginiana 

Metopium toxiferum 

Mikania scandens 

Myrica cerifera 

Myrsine f loridana 

Panicum j oorii 

Parthenocissus quinquefolia 

Persea borbonia 

Psychotria sulzneri 

Schinus terebinthifolius 

Tetrazggia bicolor 

Thelypteris kunthii 

Toxicondendron radicans 

Vitis munsoniana 

Zeuxine s trateumatica 

% 

K * 

3 X * 

?t 

* 

3 

Y 3 * 

3t * * 

3 

3 

* 3 * 

* 3 

EX 3 3 

it 

3 3 

* Yr 

* 

E3 

Total 22 :5 7 
APPENDIX 1. 

PRESENCE IN SIZE CLASS 

1 2 3 

PRESENCE IN SIZE CLASS 

SPECIES 1 2 3 SPECIES 

PLOT 7 (Cont . ) PLOT 10 

Sisyrinchium miamiense 

Solidago sempervirens 

var. mexicana 

Spermacoce tetraquetra 

Spilanthes americana 

Andropogon glomeratus 

Baccharis halimifolia * Boehmeria cylindrica * 

* 

E * 

* 

E * 

Total 38 

Eupatorium coelestinum 

Hypericum hypericoides 

var. hypericoides 

Ilex cassine 

 i is me ria trifoliata 

Vicia acutifolia 

Vigna uteola 

Zeuxine strateumatica 

Psychotria sulzneri 

Schinus terebinthifolius 

PLOT 9 Spermacoce assurgens 

Thelyptens kunthii 

Andropogon glomeratus 'Vitis aestivalis 

Baccharis glomeruliflora 

Bidens alba 

Bumelia salicifolia 

Ludwigia octovalvis 

ssp. octovalvis 

Metopium toxiferum 

Morinda royoc 

Myrica cerifera 

Total 11 7 5 

PLOT 12 

Andropogon glomeratus 

Baccharis halimiflora 

Bacopa monnieri 

Boehmeria cylindrica 

centella asiatica 

Cirsium horridulum 

Parthenocissus quinquefolia 

Psychotria sulzneri 
APPENDIX 1. 

SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 

PLOT 9 (Cont.) PLOT 12 (Cont. ) 

Schinus terebinthifolius E 3" x * 

Spermacoce assurgens 3c 

Te trazygia bicoloFThelypteris kunthii 

Vitis munsoniana 

PLOT 11 CO 

Acacia pinetorum 

kndropogon glomeratus 

Baccharis halimiflora 

Caperonia casteneifolia 

Cyperus ligularis 

Dichromena colorata 

Diodia virainiana 

Erigeron quercifolius 

Eupatorium capillifolium 

Eupatorium coelestinum 

Ludwiria octovalvis 

ssp. octovalvis 

Ludwigia microcarpa 

Lythrum lineare 

Melanthera angustifolia 

3t 

Total 12 7 3 

Cladium jamaicensis 

Crinum americanum 

Dichromena colorata 

Diodia virginica 

Erianthus giganteus 

Erigeron quercifolius 

Eupatorium coelestinum 

Eupatorium mikaniodes 

Hydrocotyle umbellata 

Hyptis alata var. stenophylla 

- Ilex cassine 

Ipomoea sagittata 

Juncus megacephalus 

Justicia angusta 

Kosteletzya virginica 

Lobelia glandulosa 

Ludwigia microcarpa 

Ludwigia octovalvis 

ssp. octovalvis 

Lythrum lineare 

Melanthera angustifolia 

Mikania scandens 

Muhlenbergia filipes 

Myrica cerifera 
APPENDIX 1. 

SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 

PLOT 11 (Cont.) 

Mikania scandens 

Phyla nodiflora 

Phyllanthus caroliniensis 

ssp. saxicola 

Polygonum hydropiperoides 

Sarcostemma clausum 

Schinus terebinthifolius 

Spermacoce assurgens 

Teucrium canadense 

var. hypoleucum 

Verbena scabra 

Vigna luteola 

PLOT 13 

Ampelopsis arborea 

Ardisia solanacea 

Baccharis halimifolia 

Crinum americanum 

Ilex cassine 

I4yrica cerif era 

Myrsine floridana 

Psychotria sulzneri 

* * 

* * 

* 

Total 20 9 1 

PLOT 12 (Cont. ) 

Panicum caerulescens 

Passiflora suberosa 

Phyla nodiflora 

Pluchea rosea 

Proserpinaca palustris 

var. palustris 

Rhyncospora microcarpa 

L Sco~aria dulcis 

Setaria geniculata 

Sisyrinchium miamiense 

Solidaeo leavenworthii 

Solidago sempervirens 

var. mexicana 

Spermacoce assurgens 

Teucrium canadense 

var. hypoleucum 

Thelyptens kuntllii 

PLOT 14 

Acrostichum danaeifolium 

Andropogon glomeratus 

Annona glabra 

Total 40 9 0 
APPENDIX 1. 

SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 

PLOT 13 (Cont. ) PLOT 14 (Cont. ) 

Salix caroliniana 

Schinus terebinthifolius 

Thelypteris kunthii 

Vitis aestivalis 

Vitis munsoniana 

PLOT 15 

E 

Total 

Alternanthera philoxeroides 

Andropogon glomeratus 

Baccharis halimifolia 

Boehmeria cylindrica 

var. drummondiana 

- 

Commelina diffusa 

Cyperus surinamensis 

Erechtites hieracifolia 

var. hieracifolia 

Erigeron quercifolius 

Galium obtusum var. floridanum 

Guettarda elliptica 

Ludwigia octovalvis 

ssp. octovalvis 

Myrica cerifera 

Ardisia solanacea 

Aster caroliniensis 

Baccharis halimifolia 

Boehmeria cylindrica 

Chrysobalanus icacco 

Cladium jamaicensis 

Crinum americanum 

Dichromena colorata 

Diodia virginica 

Eupatorium coelestium 

Hyptis alata 

- Ilex cassine 

Ipomoea sagittata 

-- 

Justicia angusta 

Kosteletzya virginica 

Ludwigia alata 

Ludwigia microcarpa 

Ludwigia octovalvis 

ssp. octovalvis 

Ludwigia spathulifolia 

Metapium toxiferum 

Mikania scandens 

Myrica cerifera 

Myrsine floridana 
APPENDIX 1. 

PRESENCE IN SIZE CLASS 

1 2 3 

PRESENCE IN SIZE CLASS 

SPECIES 1 2 3 SPECIES 

PLOT 15 (Cont. ) PLOT 14 (Cont. ) 

Phyllanthus amarus 

Pluchea rosea 

Sesbania exaltata 

Solidago sempervirens 

var. mexicana 

Thelypteris kunthii 

Panicum hemitomon 

Parthenocissus quinquefolia 

Persea borbonia 

Phyla nodiflora 

Pluchea rosea. 

Proserpinaca palustris 

Total var. palustris 4 

F 

PLOT 17 

Rhynchospora inundata 

Salix caroliniana 

Solidago leavenworthii 

Acrostichum danaeifolium 

Ampelopsis arborea 

Ardisia solanacea 

Baccharis halimifolia 

Boehmeria cylindrica 

var . drummondiana 

Teucrium canadense 

var. hypoleucum 

Thelypteris kunthii 

Tillandsia fasciculata 

Utricularia biflora 

Vigna luteola 

Diodia virginiana Total 34 13 5 

Eupatorium coelestinum 

-- Ficus aurea 

Hydrocotyle verticillata 

Hgpericum hypericoides 

var. hypericoides 

- Ilex cassine 

Myrica cerifera 

Myrsine floridana 

PLOT 16 

Ampelopsis arborea 

Ardisia solanacea 

Baccharis halimifolia 

Boehmeria cylindrica 

Bumelia celastrina 
APPENDIX 1. 

PRESENCE IN SIZE CLASS 

1 2 3 SPECIES 

PRESENCE IN SIZE CLASS 

SPECIES 1 2 3 

PLOT 17 (~ont.) 

Panicum joorii 

PLOT I6 (Co-nt. ) 

Crinum americanum 

Parthenocissus quinquefolla - 

Persea borbonia 

Psychotria sulzneri 

Hydrocotyle verticillata 

Hypericum hypericoides 

var. hypericoides 

Salix caroliniana 

Schinus terebinthifolius 

- - 

- Ilex cassine 

Ludwigia octovalvis 

Thelypteris kunthii it ssp. octovalvis 

Myrica cerifera 

Myrsine f loridana 

Parthenocissus quinquefolia 

Persea borbonia 

Psychotria sulzneri 

Rhgnchospora inundata 

Vitis aestivalis 3C 

Total 14 11 7 

PLOT 19 

Acrostichum danaeifolium 

Ammannia latifolia Salix caroliniana 

Andropogon glomeratus Schinus terebinthifolius 

Baccharis halimifolia 

Cephalanthus occidentalis 

Teucrium canadense 9 

ii 

?t 

* 

Total 14 18 4 

var. hypoleucum 

Cladium jamaicensis Thelypteris kunthii 

Cyncotonum mitreola 

Dichromena colorata 

Eupatorium coelestinum 

Eustachys glauca 

.- Ilex cassine 

Justicia angusta 

Ludwigia alata 

Toxicodendron radicans 

Vitis aestivalis 
APPENDIX 1 . 

SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 

PLOT 19 (Cont. ) PLOT 18 

Lythrum lineare 

Magnolia virpiniana 

Mikania scandens 

Myrica cerifera 

Myrsine floridana 

Panicum hemitomon 

Pluchea rosea 

Proserpinaca palustris 

var. palustris 

Rhynchosia minima 

Rhynchospora inundata 

Salix caroliniana 

Taxodium distichum 

PLOT 21 

Ambrosia artemisiifolia 

Ammannia latif olia 

Ampelopsis arborea 

Andropogon glomeratus 

Baccharis halimifolia 

,Cynoctonum mitreola 

Cyperus surinamensis 

E 

Total 

Andropogon glomeratus - 

Bacopa monnieri 

Baccharis halimifolia 

Boehmeria cylindrica 

Centella asiatica 

Cirsium horridulum 

Cladium jamaicensis 

Crinum americanum 

Cynoctonum mitreola 

Diodia virginiana 

Eupatorium coelestinum 

Eustachys glauca 

Hydrocotyle verticillata 

Hyptis alata var. stenophylla 

Ipomoea sagittata 

Kosteletzya virginiana 

Ludwigia alata 

Ludwigia microcarpa 

Ludwigia octovalvis -- ~~p ~ -- 

ssp. octovalvis 

Lythrum lineare 

Melanthera angustifol 

Mikania scandens 

Muhlenbergia filipes 
APPENDIX 1. 

SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 

PLOT 21 (Cont. ) 

Dichromena colorata 

Eupatorium coelestinum 

Eustachys glauca 

Hydrocotyle umbellata 

Hyptis alata var. stenophylla 

Imperata brasiliensis 

Ipomoea sagittata 

Kosteletzya virginica 

Ludwigia alata 

Ludwigia nicrocarpa 

Ludwigia octovalvis 

ssp. octovalvis 

Ludwigia repens 

Lythrum lineare 

Melanthera angustifolia 

Mikania scandens 

Panicum caerulescens 

Panicum hemitomon 

Panicum polycaulon 

Persea borbonia 

Pluchea rosea 

Rhyncospora inundata 

Sabatia grandiflora 

Setaria geniculata 

Spermacoce prostrata 

PLOT 18 (cont.) 

Panicum hemitomom 

Panicum polycaulon 

Passiflora suberosa 

Phyla nodiflora 

Phyllanthus amarus 

PLOT 20 

Ampelopsis arborea 

Andropogon glomeratus 

Baccharis halimifolia 

Boehmeria cylindrica 

Crinum americanum 

Cgperus surinamensis 

Dichromena colorata 

Galium obtusum var. floridanurn 

Hydrocotyle umbellata 

Hyptis alata 

Ludwigia microcarpa 

Muhlenbergia filipes 

Myrica cerifera 

Parthenocissus quenquefolia 

Persea borbonia 

Phyla nodiflora 

re 

+t 

3t 

E * 

X 

Total 25 9 0 
APPENDIX 1. 

SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 SPECIES 

PRESENCE IN SIZE CLASS 

1 2 3 

PLOT 21 (Cont. ) , PLOT 20 (Cont.) 

Sporobolus domingensis 

Verbena bonariensis 

Vicia acutifolia 

Vigna luteola 

* 

E * * 

* 

Total 36 0 0 

Polygonurn hydropiperoides 

Proserpinaca palustris 

var. palustrius 

Ptilinium capillaceum 

Salix caroliniana 

~oxicodendron radicans +t 

Total 17 7 4 
- 1 P.I.U. URBAN b REG. DOCS. LIBRARY