ABSTRACT

A FLORISTIC STUDY OF A FORMER LAND BRIDGE IN THE BAHAMA ARCHIPELAGO

by Mark Leo Daniels

A floristic study of communities was conducted on the islands of Eleuthera, Little San Salvador, and Cat Island. The objectives of this analysis were to explore the composition and distribution of dry forest communities among the three study sites, and to propose new classification types to facilitate plant conservation in , as outlined by the International Classification of Ecological Communities for vegetation types. Unconstrained ordination, cluster analysis and indicator species analysis indicated two dominant forest types across the three study sites: the Coccothrinax argentata-Reynosia septentironalis and diversifolia- simaruba Alliances. Nested within these forest types were 8 species associations: Coccothrinax argentata– Reynosia septentrionalis – keyense association; flavum – Jacquinia keyensis – Casasia clusiifolia association; Acacia choriophylla - Pithcellobium keyense - Guapira discolor association; - americanum-Pseudophoenix sargentii association; Maytenus buxifolia- Sideroxylon salicifolium association; Exothea paniculata-Tabebuia bahamensis- toxiferum association; Guaiacum sanctum association; Eugenia foetida- Exostema caribeaum-Bourreria succulenta association.

A FLORISTIC STUDY OF A FORMER LAND BRIDGE IN THE BAHAMA ARCHIPELAGO

A Thesis

Submitted to the

Faculty of Miami University

in partial fulfillment of

the requirements for the degree of

Master of Science

by

Mark Leo Daniels

Miami University

Oxford, Ohio

2016

Advisor: Dr. Michael A. Vincent

Reader: Dr. James Hickey

Reader: Dr. Richard C. Moore

©2016 Mark Leo Daniels

This Thesis titled

A FLORISTIC STUDY OF A FORMER LAND BRIDGE IN THE BAHAMA ARCHIPELAGO

by

Mark Leo Daniels

has been approved for publication by

The College of Arts and Science

and

Department of Biology

______Michael A. Vincent

______R. James Hickey

______Richard C. Moore

Table of Contents

Page

List of Tables……………………………………………………………………………..iv

List of Figures……………………………………………………………………………..v

Acknowledgements…………………………………………………………………….…vi

Introduction………………………………………………………………………………..1

Methods……………………………………………………………………………………7

Study Sites………………………………………………………………………...7

Data Collection…………………………………………………………………....9

Data Analysis…………………………………………………………………….12

Results……………………………………………………………………………………13

Island Summary Statistics………………………….…………………………….13

Ordination, Clustering and Indicator Species Analysis – Layer………...…17

Ordination, Clustering and Indicator Species Analysis – Layer………….26

Discussion………………………………………………………………………………..27

Clustering Patterns……………………………………………………………….27

Taxon Distribution……………………………………………………………….29

Rare and Endemic Species……………………………………………………….32

Classification of Caribbean Plant Communities…………………………………33

Community Classifications and Island Vegetation Maps.……………………….36

Implications for Plant Conservation in the Bahama Archipelago….………………...….41

Literature Cited…………………………………………………………………………..44

iii

List of Tables

Table Page

1. Summary statistics of plot data……………………………………………………...14

2. Pearson correlation coefficient values………………………………………………25

3.Taxa distribution across study sties………………………………………………….30

iv

List of Figures Figure Page 1. Map of The Bahama Archipelago…………………………………………………...….2 2. Map of study sites on Eleuthera, Little San Salvador and Cat Island…………………..7

3. Map of plot locations on Eleuthera……………………………………………………10

4. Map of plot locations on Little San Salvador…………………………………………11

5. Map of plot locations on Cat Island…………………………………………………...11

6. Schematic diagram of plot layout……………………………………………………..12

7. Boxplot diagrams of density, basal area and species richness by study site…………..16

8. Unconstrained ordination diagram with NMDS of tree plots………………………....17

9. Constrained ordination diagram with CCA of tree plots…………………………...…18

10. Ward’s cluster dendrogram of tree layer Groups 1 and 2…………………..………..19

11. Boxplot diagram of elevation and distance from coastline for Groups 1 and 2……..20

12. Boxplot diagram of basal area and species richness for Groups 1 and 2…………….20

13. Ward’s cluster dendrogram of tree layer subgroups 1-7……….…………...………..21

14. Unconstrained ordination diagram with NMDS of tree subgroups 1-7………...…....21

15. Scatterplot diagrams of dependent versus independent variables……………………23

16. Unconstrained ordination diagram with NMDS of shrub groups 1 and 2 with environmental vectors………………………………………………………………..23

17. Unconstrained ordination diagram with NMDS of tree plots by island………...…...24

18. Unconstrained ordination diagram with NMDS of shrub plots by island…………...25

19. Species accumulation curves for plots at study sites………………………………...26

20. Undescribed species of Cynanchum sp. from Little San Salvador…………………..31

21. Bahamian endemic species Thouinia discolor and Waltheria bahamensis………….33

22. Vegetation map of plant communities at Eleuthera study site……….………………37

23. Vegetation map of plant communities at Little San Salvador study site………….....39

24. Vegetation map of plant communities at Cat Island study site………………………41

v

Acknowledgements

I would like to thank my advisor Dr. Michael A. Vincent for his guidance and support throughout this process. My co-advisors Dr. R. James Hickey and Dr. Richard C. Moore were instrumental in providing constructive critique and instilling confidence in my abilities.

Thanks to Dr. Janet Franklin and Dr. Julie Ripplinger for graciously providing their expertise in statistical analyses of dry forest communities in the Caribbean. Your assistance was central to the successful completion of this project and I am forever grateful.

I want to acknowledge the management and staff of The Bahamas National Trust and The Leon Levy Native Plant Preserve. Dr. Ethan Freid, Eric Carey and Falon Cartwright were essential to the execution of my fieldwork, thank you for providing resources and logistical support for me while in The Bahamas. Thank you to the management and staff of Half Moon Cay for facilitating access to Little San Salvador and accommodating me during my field work on island.

Sincere gratitude goes to Shelby White and The Leon Levy Foundation for their moral and financial support in my pursuit of an advanced degree. Thank for you inspiring me to take on such a great challenge.

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INTRODUCTION Island floras have the reputation as being living laboratories engaged in natural experiments of evolution. The or Caribbean Archipelago divides the Atlantic Ocean from The Caribbean Sea, and is made up of three smaller island chains: the Bahama Archipelago, the Greater Antilles, and the Lesser Antilles. The flora of the region, comprising 231 families, 1447 indigenous genera and ca. 10, 948 species of (Acevedo-Rodriguez & Strong 2011), is strongly influenced by continental Central and South America. Endemism is relatively high; 13.2% of the genera and 72% of species are endemic to the West Indies (Acevedo-Rodriguez & Strong 2011). The historical biogeography of this region is complex due to the differing ages of the islands, tectonic movements, and sea level changes that have occurred throughout the millennia. The islands of the Caribbean vary widely in degree of isolation, island size and shape, landscape, geology, climate, and moisture patterns, resulting in a diversity of habitats and microclimates that support endemic species. The Caribbean is designated as one of the 35 global hotspots for conservation, characterized by high levels of endemics and having lost more than 70% of their natural habitats (Mittermeier et al. 2011). The Caribbean Island Hotspot contributes high biodiversity from a relatively small land area, earning its global conservation priority status. The islands of the Bahama Archipelago, The Bahamas, are emergent peaks of the limestone-capped Bahamas Platform, spanning 1,400 km between the southeast coast of and the northeast coast of . Territorially, the archipelago consists of the island nations of The Bahamas and The (Figure 1). The island land mass of the Bahama Archipelago covers 13,880 km2, and is made up of approximately 35 islands, hundreds of cays and thousands of exposed, vegetated rocks. The flora of The Bahamas comprises 136 families, 654 genera and 1351 species of vascular plants (Acevedo- Rodriguez and Strong 2011). The most speciose families are Poaceae (144) and (128), and the most speciose is Euphorbia (30) (Acevedo-Rodriguez and Strong 2011). Endemic plant species of The Bahamas had previously been numbered at 114 (Correll and Correll 1982). However, a recent review of endemism in the flora has decreased the number of endemics to 89 species within 54 genera and 29 families (Freid et al. 2014). The endemics make up approximately 6% of the total flora, and the most

1 endemic rich families represented in the archipelago are the (14), (11) and (9). Biogeographical analyses of endemic species distribution throughout the Bahama archipelago has resolved a clustering of endemic species into northern (35 species), central (38 species) and southern (59 species) island groupings. Fifty endemic species are restricted to one (31) or two (19) island groupings, and are a high priority for native plant conservation efforts in the archipelago.

Figure 1. Map of the Bahama Archipelago. (Hearty and Neumann, 2001)

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The flora of the Bahama archipelago is most akin to that of Florida, Cuba and Hispaniola. Gleason and Cronquist (1964), in describing The Vegetation of North America, describe the West Indian Province as a tropical flora extending from the southern tip of Florida down through the Florida Keys and into the Bahamas and Greater Antilles. The vegetation of The West Indian Province is grouped into four types; coastal swamps, inland swamps, hammock forests, and pinelands. Within these communities are found tropical plant species common to The Bahama Archipelago, which are at the northernmost extent of their range in Florida. Dominant species within these plant communities include Rhizophora mangle in the coastal swamps, Cladium jamaicense of the inland swamps, Bursera simruba within the hammocks, and Pinus caribaea dominating the limestone pinelands (Gleason & Cronquist 1964). The native Exostema caribaea is Antillean in origin, and has spread northward into The Bahama Archipelago by its wind dispersed seeds (McDowell et al. 2003). The pineland species Pinus caribaea var. bahamensis spread to the archipelago in a similar manner from Central America (Adams and Jackson 1997; Jardon- Barbolla et al. 2010), and dominates the pinelands on the northernmost islands of Grand Bahama, New Providence, Abaco and Andros. The orchid diversity of The Bahama Archipelago is closest in affinity to the Isla de Juventud, Mona Island and Anegada in The Greater Antilles (Trejo-Torres and Ackerman. 2001). Long distance dispersal by birds has contributed to the distribution of Neolaugeria densiflora (Moynihan and Watson 2000) and species of Ernodea and Erithalis (Negron-Ortiz and Watson 2003; Bancroft and Bowman 1994) to The Bahama Archipelago from the Lesser Antilles and Florida. A recent analysis of regional variation in Caribbean dry forests examined species variation along an environmental gradient using floristic data from , The US Virgin Islands and the islands of Abaco and Eleuthera in the Bahamas (Franklin et al. 2015). The regional analysis indicates a similarity of Bahamian dry forests dominated by and to that of other dry forest systems found throughout the Caribbean, suggesting a region-wide dry forest type for south Florida, the Bahamas, and the Greater Antilles (Franklin et al. 2015). Variation in species composition among interior coppice communities on Abaco and Eleuthera corresponds partially to the temperature and moisture gradient that exists between the northern and southern islands, and also correlates with the level of rockiness in plots (Franklin et al. 2015).

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Description and classification of plant communities is central to conservation planning and resource management. Vegetation communities in the Bahama Archipelago have generally been classified by their physiognomy and habitat association. Northrop and Northrop (1907) described the vegetation communities of Andros as maritime or coast flora, ‘coppet’, pine barren, savannas and swash. Correll and Correll (1982) also provided general classifications for vegetation communities found throughout the archipelago, classifying communities as coastal rock, sand strand, coastal coppice/whiteland, interior coppice/blackland, fresh water formations, tidal flats and salt marshes, , and the pinelands. Finer levels of plant assemblages, such as alliances and associations, provide quality data for describing and mapping vegetation communities. Coker (1905), during his exploration of the Bahama Islands, recognized ten associations during his expeditions; Ipomoae pes-caprae, Uniola-Tournefortia, Pithcellobium-, Erithalis-Reynosia, Silver Palm, Lantana-Corchorus, Tournefortia-Suriana, Distichlis-Ambrosia, Cocoa plum, and Inodes-Lantana associations. More recent classifications of plant communities were designated for interior and coastal dry evergreen broadleaf formations on Andros (Smith and Vankat, 1992), and provides the following dominance-type classifications: Metopium toxiferum-Coccoloba diversifolia and Coccoloba diversifolia coastal coppice; Metopium toxiferum-Coccoloba diversifolia, Metopium toxiferum-Exothea paniculata, and Exothea paniculata-Bursera simaruba-Metopium toxiferum interior coppice. Floral community data from the islands of Abaco (Freid, unpublished), Crooked Island (Freid, unpublished), San Salvador (Kass and Stephens 1990) and the Exumas (Morrison 1997; Freid, unpublished) have provided floristic data relevant to understanding the variation in species composition among islands within the Bahama Archipelago. The Nature Conservancy assembled the Caribbean Vegetation Ecology Working Group with the purpose of executing the objectives of The Caribbean Vegetation Classification and Atlas Project (Aceres-Mallea et al. 1999). The main objectives were to develop a standardized classification system for the Caribbean and to produce a land cover and vegetation atlas for member countries. The group proposed the International Classification of Ecological Communities (ICEC) as a system for unifying terminology when classifying Caribbean vegetation types, facilitating regional comparisons of vegetation communities. The ICEC classification system is adopted from the U.S. National Vegetation

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Classification, a seven tier hierarchy which uses physiognomic characters for the first five tiers (Class-Subclass-Group-Subgroup-Formation), and floristic data for the finest two levels of classification, Alliance and Association. The ICEC currently recognizes 104 formations, 187 alliances and 199 associations for the Caribbean, out of an estimated 350 alliances and 750-800 associations predicted for the region (Aceres-Mallea et al. 1999). Only one dry forest alliance type in the current ICEC for The Caribbean is found within the Bahamas and that is the Reynosia septentrionalis - Sideroxylon americanum - Pithecellobium keyense - Jacquinia keyensis forest; it is analogous to the whiteland communities of Correll and Correll (1982). Further botanical exploration and description of island communities throughout the Bahama Archipelago will likely increase the number of recognized Alliances and Associations for the region, and will have important implications for conservation and land use policies in the country. As a signatory of the Convention on Biological Diversity, The Bahamas has committed to the long term objective of the Updated Global Strategy for Plant Conservation (GSPC) which is to stop the decline of global plant diversity. Plant conservation efforts in the Bahama Archipelago face a number of challenges under the increasing threat of through human disturbance and climate associated sea level rise. Among the strategies for effective plant conservation are increased public environmental education programs, as well as a combination of in-situ and ex-situ conservation management. Extensive field work and herbarium research is needed to determine distributions of rare and endemic species found throughout the archipelago. Such data are important for the development of threatened species lists that in turn influence long term protection programs for endemic species (Carey et al. 2014).

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The goal of this study is to explore, describe and classify the plant communities at study sites on the adjacent islands of Eleuthera, Little San Salvador and Cat Island in the central Bahamas. A lack of floristic data for these local communities and the potential for conservation and sustainable land management has prompted this project. It is intended that this research will identify new dry forest alliances and associations for the ICEC’s recognized vegetation types for The Bahamas, and enhance local and regional understanding of compositional variation between nearby islands in the central Bahamas.

Questions to be answered by this project:

What are the floral compositions at Bannerman Town, Orange Creek and Little San Salvador?

What are the dominant vegetation types are found at Bannerman Town, Orange Creek and Little San Salvador and what plant species do they support?

What are the species alliances and associations that comprise the dry forest communities found at the study sites?

How does species composition vary within dry forests communities and which taxa are shared and unshared among the three study sites?

How are endemic plant species distributed across the three study sites?

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METHODS

STUDY SITES The three study sites are located on the adjacent islands of Eleuthera (EL), Little San Salvador (LSS), and Cat Island (CAT) located in the central Bahamas (Figure 2). During the Pleistocene, at the peak of the Winconsin Glaciation, and until approximately 12,000 years ago, sea levels were as much as 130m lower than present, exposing The Great Bahama Bank as one landmass. The islands of Andros, New Providence, the Exumas, Cat Island, the Islands, Ragged Islands, and Eleuthera formed a single landmass called Paleoprovidence (Campbell, 1978). Eleuthera and Cat Island were connected to Little San Salvador, and comprises the easternmost edge of the Great Bahama Bank facing the Atlantic Ocean. The present interglacial period of the Holocene has raised global sea levels and submerged most of the Great and Little Bahama Banks, resulting in the current configuration of islands for the archipelago.

Figure 2. Map depicting study sites Lighthouse Point on Eleuthera (EL), Orange Creek on Cat Island (CI) and Little San Salvador (LSS). Google Earth V 7.1.5.1557 (September 13, 2015) Central Bahama Islands. 24.633040°, -75.894542°, Eye alt 61.22 km. Digital Globe 2016. http://www.earth.google.com [June 1, 2016]

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At the southernmost end of Eleuthera is Bannerman Town, a settlement that has historically been home to the Millar’s Plantation, a slave plantation that cultivated cotton (Gossypium hirsutum) and Sisal (Agave sisalana). The settlement is currently sparsely populated by descendants of freed slaves, and areas south of Bannerman town to East End Point (or Lighthouse Point) are used by locals for subsistence farming, land crab harvesting and recreation. The peninsula is oriented north to south with a windward eastern and leeward western shore, and is approximately 2km at its widest. A central Pleistocene ridge extends up to 31m above sea level, and is flanked by sandy Holocene dune ridges parallel to the coastline. There are three hypersaline ponds in the interior of the landform: ‘Shad Pond’, ‘White Pond’ and the largest, ‘Big Pond’, stretching 2km along the Atlantic shore. This study site encompasses approximately 3.6km2 (360 ha) and is hereafter referred to as Lighthouse Point. The 2,400 acre (971 ha) island of Little San Salvador (24°34’ N 75°54’ W), is situated between the southern tip of Eleuthera and the northern tip of Cat Island. Little San Salvador is oriented east to west. The topography includes ridges up to 20m that run the length of the island, a large central lagoon with coastal marsh and tidal flats along its edge, sandy and rocky shorelines around the island’s perimeter and a few wetlands within the island’s interior. Historically the island had been inhabited by a small number of Cat Island families farming Sisal and subsistence crops. The island is currently privately owned by the Holland Line America, which uses it as the destination point ‘Half Moon Cay’ for its cruise ship passengers. Approximately 2% of the 2,400 acre island has been developed for recreation and island operations, the other 98% is dedicated as a wilderness sanctuary for preservation of the native flora and fauna of the island. At the northernmost tip of Cat Island are the settlements of Orange Creek and Bain Town. Located along the western, leeward shore, the settlements have a history of occupation dating back to the late 1700s. Traditionally the area has supported subsistence farming in the ‘blackland’ and ‘redland’ areas surrounding the settlements, as well as harvesting of land crabs and hunting of wild birds and feral pigs. The region surrounding the settlements to the windward ‘north shore’ remain largely undeveloped, only small scale boutique hotels scatter the protected, western shorelines. The 30km2 (~2800 ha) of the defined study site extends from ‘Dickey Road’ northward to ‘North End Point’, and is 7.5km

8 at its widest. Pleistocene ridges create a rolling landscape with some peaks extending 30m above sea level. A series of large saltwater ponds or ‘blue holes’ are scattered across the landscape at the innermost low lying areas of the island, and freshwater wetlands occurring closer to the coastline.

DATA COLLECTION Field work was carried out during the months of June to August 2015 on Eleuthera and Cat Island, December 2015-January2016 on Eleuthera and Little San Salvador, and March 2016 on Cat Island. For Eleuthera and Cat Island, the study sites were overlaid with a series of E- W transects, spaced at least 500m apart and spanning the width of the island. Plots were placed at least 200m apart along transects, and sought to record dry forest composition between windward and leeward shorelines. The E-W orientation and narrow width of Little San Salvador required only one transect to cover from the western to the eastern end of the island, and plots were spaced at least 200m apart along this transect (Figures 3-5). Each plot was located using predetermined coordinates, and the center point established at the nearest tree. Circular plots of 10m, 3m, and 1m, radius were surveyed to assess the tree, shrub and herb layers respectively (Figure 6). In the 10m plots, woody stems equal to or greater than 4cm at DBH (Diameter at Breast Height: 1.3m) were measured and identified to the most exact taxonomic classification. In the 3m subplots, woody less than 4cm DBH and rooted within the boundaries of the plot were identified and counted for shrubs. In the 1m subplots, non-woody, herbaceous grasses, vines and epiphytes were identified and counted for individuals rooted in the subplot. The distance of each plot center to the nearest hide tide mark was measured using Google Earth. Plot elevation was measured at the plot center using a Garmin GPSMAP 64st device. For each plot, a physical description of habitat and surrounding vegetation was recorded. Substrate type was categorized by color and texture: Organic soils are brown to dark brown in color, with conspicuous leafy humus layer; Lateritic soils are red to reddish brown and clay-like in texture, at times becoming very compact; Sandy soils consist mostly of unconsolidated white mineral carbonates; Muck soils are grey or brown and are permanently saturated. Walkabout surveys were conducted in non-forested areas not sampled by plots in order to classify other plant communities within the study sites.

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Taxa were identified using Correll and Correll (1982) and updated nomenclature following Acevedo-Rodriguez and Strong (2011). Voucher specimens were collected from the individual study sites for each species identified within a plot. Additional specimens were collected from areas surrounding plots to show total diversity of the study area. Voucher specimens are housed at the W.S. Turrell Herbarium, Miami University, Oxford, Ohio.

Figure 3. Map depicting plot locations at Lighthouse Point, Eleuthera (EL). Google Earth V 7.1.5.1557 (January 19, 2014) Eleuthera, The Bahamas. 24.629037°, -75.159774°, Eye alt 5.12 km. CNES/Astruim 2016. http://www.earth.google.com [June 1, 2016]

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Figure 4. Map depicting plot locations on Little San Salvador (LSS). Google Earth V 7.1.5.1557 (October 8, 2015) Little San Salvador, The Bahamas. 24.574910°, -75.930216°, Eye alt 7.85 km. Digital Globe 2016. http://www.earth.google.com [June 1, 2016]

Figure 5. Map depicting plot locations at Orange Creek and Bain Town, Cat Island (CI). Google Earth V 7.1.5.1557 (December 13, 2015) Cat Island, The Bahamas. 24.666454°, -75.715014°, Eye alt 9.78 km. Digital Globe 2016. http://www.earth.google.com [June 1, 2016]

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Figure 6. Schematic diagram of plot design used in this study. The tree plots were 10m in radius (314.16m^2), shrub plots were 3m in radius (28.27m^2), and herb plots were 1m in radius (3.14m^2).

DATA ANALYSIS Statistical analyses were conducted using the software ‘R’ (R Development Core Team 2012) and its ‘vegan’ package (Oksanen et al. 2011). Raw data from plots were used to calculate measures of abundance to identify the most important tree, shrub and herbaceous species across the study sites. DBH and count data from tree plots were used to calculate measures of density, dominance and frequency for all tree species identified. Absolute density was calculated as number of individuals per plot and absolute dominance as total basal area per species within a plot. Importance values for tree species were calculated using the average of relative density, relative dominance and relative frequency. Importance values for species within nested shrub and herb plots were calculated using the average of their relative density and relative frequency. Importance value matrices for the tree and shrub layers were constructed with plot names on the y axis and species names on the x axis, and subsequently transformed to dissimilarity matrices using Jaccard’s index (Peet and Roberts, 2013). Each distance matrix was analyzed separately via ordination, clustering and indicator species analysis to

12 determine assemblages of species, the dominant species within these groups, and which environmental variables may be exerting an influence on species assemblages. The significance of compositional differences between groups identified by cluster analysis was evaluated using PERMANOVA (Anderson, 2001), and differences visualized using unconstrained ordination with NMDS (Clarke, 1993). The relationships of recorded environmental variables (lat/long, distance from coast, elevation and soil type) to species composition were evaluated using Canonical Correspondence Analysis (ter Braak 1987). Indicator species analysis (Dufrene and Legendre 1997) was used to identify indicator species for groups produced by cluster analysis, and to generate a dominance type classification for groups identified by clustering.

RESULTS ISLAND SUMMARY STATISTICS A total of 75 plots were surveyed at the three study sites on the islands of Eleuthera (31 plots, 10,712.8 m2), Little San Salvador (11 plots, 3801.3 m2) and Cat Island (33 plots, 11,404 m2) (Table 1). Plot elevation ranged from 1-36 masl, and distance of plot center from coastline ranged from 7-2615 meters. For each stratification layer, total area surveyed was 2.34 ha (23,550 m2) for , 0.212 ha (2,120 m2) for shrubs, and 0.024 ha (236 m2) for herbs. Grouped by substrate type, the 75 plots were distributed as muck (2), lateritic (5), organic (34) and sandy (34). For each study site, the distribution of substrate types were as follows: Lighthouse Point 12 sandy, 17 organic, 1 muck and 1 lateritic; Little San Salvador 7 sandy and 4 organic; Orange Creek 15 sandy, 13 organic, 1 muck and 4 lateritic. Plot data for all sites recorded a total diversity of 124 taxa within 103 genera and 49 families, the most speciose families being Rubiaceae (13 species) and Fabaceae (9 species). The total number of taxa recorded at the tree, shrub and herb layers at each site is as follows: Lighthouse Point on Eleuthera, 82 species in 41 families; Orange Creek on Cat Island 87 species in 40 families; Little San Salvador 40 species in 27 families. Across all sites, the tree layer contained 63 species in 31 families, the shrub layer contained 81 species in 35 families and the herbaceous layer contained 30 species in 18 families.

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Table 1. Summary statistics of plot data recorded from 75 plots on the islands of Eleuthera (EL), Cat Island (CI) and Little San Salvador (LSS)

Average species richness per tree plot was highest for Cat Island with 13 species (s=4.9 species), 11 species for Eleuthera (s=5.6 species) and 9 species on Little San Salvador (s=2.9 species). Endemic species captured by plots were Thouinia discolor (Sapindaceae), Bursera frenningae (), Varronia bahamensis (Boraginaceae), Spathelia bahamensis () and Agave braceana (Asparagaceae). The average density of tree plots on each island were as follows: Eleuthera plots averaged 1577 trees ha-1 (range: 127.3 – 2896.7 trees ha-1, sd= 907.49 trees ha-1); Cat Island plots 2381 trees ha-1 (range: 445.6 – 6652.7 trees ha-1, sd=1411.7 trees ha-1); Little San Salvador plots 1299 trees ha-1 (range: 350.1 – 2100.8 trees ha-1, s=554.59 trees ha-1). Average basal area for tree plots per island were as follows: 0.472 m2 (range: 0.066 – 0.858=9 m2, sd=0.246 m2) on Eleuthera; 0.611m2 (range: 0.125 – 1.54 m2, sd=0.399m2) on

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Cat Island; 0.480 m2 (range: 0.073 – 1.077 m2, s=0.301 m2) on Little San Salvador (Figure 7). The most abundant species by basal area were Bursera simaruba (2.45 m2), Reynosia septentrionalis (1.57 m2) and Coccothrinax argentata (1.34 m2) on Eleuthera; Bursera simaruba (3.71 m2), Coccoloba diversifolia (3.64 m2) and Metopium toxiferum (2.57 m2) on Cat Island; Coccoloba diversifolia (1.71 m2), Pseudophoenix sargentii (0.97 m2) and Reynosia septentrionalis (0.46 m2) on Little San Salvador. Importance values for tree species across all study sites, with a cutoff importance value of ≥ 4.0, indicate dominant tree species as Coccoloba diversifolia (IV=6.56), Reynosia septentrionalis (IV=5.31), Bursera simaruba (IV=5.08), Guapira discolor (IV=4.89), Coccothrinax argentata (IV=4.66) and Metopium toxiferum (IV=4.22). Most important species by island were as follows (Appendix IV): Eleuthera – Reynosia septentrionalis (IV=2.48), Casuarina equisetifolia (IV=2.32), Bursera simaruba (IV=2.26) and Coccothrinax argentata (IV=2.25); Little San Salvador – Pseudophoenix sargentii (IV=1.65), Coccoloba diversifolia (IV=1.42), Reynosia septentrionalis (IV=1.09), and Coccothrinax argentata (IV=0.8); Cat Island – Coccoloba diversifolia (IV=3.4), Metopium toxiferum (IV=3.11), Bursera simaruba (IV=2.68) and Acacia choriophylla (IV=2.59). The average density for shrub plots by island was 32 individuals (range: 2 - 86 individuals, sd= 20 individuals) on Eleuthera, 57 individuals (range: 1 – 109 individuals, sd=24 individuals) on Cat Island and 49 individuals (range: 14 – 102 individuals, sd= 28 individuals) on Little San Salvador. Importance values for shrubby species across all study sites, at a cutoff importance value of ≥ 2.5, indicates dominant shrubs as Pithecellobium keyense (IV=4.93), Coccoloba diversifolia (IV=3.96), Coccothrinax argentata (IV=3.45), aculeata (IV=3.00), Erithalis fruticosa (IV=2.63) and Guapira discolor (IV=2.53) (Appendix V). For the herbaceous layer, the average density for Eleuthera plots were 5 individuals per plot (range: 0 – 20 individuals, sd= 6 individuals), Cat Island 5 individuals per plot (range: 0 – 15 individuals, sd= 4 individuals) and Little San Salvador 8 individuals per plot (range: 1 – 18 individuals, sd= 5 individuals). Importance values for herbaceous species at a cutoff importance value ≥ 2.0, indicate dominant species as havanensis (IV=15.48), Scleria lithosperma (IV=3.65), Lasciacis divaricata (IV=3.54), and Jacquinia keyensis (IV=2.70).

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Figure 7. Boxplot diagrams depicting plot density (# of individuals per plot), total basal area (m^2) and species richness (# of species per plot) for tree plots on CI, EL and LSS. Average plot density and species are higher in Cat Island plots compared to Eleuthera and Little San Salvador, and basal area relatively equal across the three sites.

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ORDINATION, CLUSTERING, AND INDICATOR SPECIES ANALYSIS

Tree layer Unconstrained ordination provides a visual representation of distances between plots based only on species composition and abundance. The unconstrained ordination diagram produced by non-metric multidimensional scaling (NMDS, k=2, stress=22.1%) identified elevation (Dim1=0.4232 and Dim 2=0.1207) and distance from coastline (Dim1=0.5236 and Dim2=0.1155) as influential vectors on the ordination space, explaining 0.19 and 0.28 of variance respectively (Figure 8). Constrained ordination provides a visual representation of distances between plots, fitted to recorded environmental variables. The first two axes for the constrained ordination by Canonical Correspondence Analysis had eigenvalues of 0.4353 and 0.3391, variance explaining 0.1350 and 0.1052. Elevation (CA1= -0.2747 and CA2= -0.3266) and distance from coast (CA1= -0.2353 and CA2= -0.2449) were both negatively correlated with CA 1 and 2 (Figure 9). Detrended Correspondence Analysis (DCA) was run in parallel, producing eigenvalues for axis 1 and 2 as 0.6291 and 0.4566.

Figure 8. Ordination diagram depicting plot distribution of 75 plots from Eleuthera (EL), Cat Island (CAT) and Little San Salvador (LSS) on first two dimensions) derived from unconstrained Non-metric Multidimensional Scaling (NMDS; stress 22.1%). Symbols indicate groups identified by cluster analysis.

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Figure 9. Ordination diagram showing the distribution of 75 plots from Eleuthera (EL), Cat Island (CAT) and Little San Salvador (LSS) on first two dimensions (CA1,CA2) derived from constrained Canonical Correspondence Analysis (CCA). Symbols indicate 2 groups defined by clustering. Vectors show correlation of environmental variables with constrained ordination axes.

Ward’s clustering method grouped plots based on minimum variance of distances within clusters, producing a cluster dendrogram to depict relationships (Figure 10). Two large groups of plots are sequestered (PERMANOVA R=0.222, P=0.001 based on 999 permutations), group 1 comprising 36 plots (16 EL, 14 CAT, 6 LSS) and group 2 comprising 38 plots (14 EL, 19 CAT, 5 LSS). Indicator species have a strong association and fidelity to a defined group and are characteristic species of the plant community that the group represents. A characteristic species with high relative abundance and frequency within a group will be less abundant and frequent outside of the group. Indicator species identified characteristic species for both groups (Indicator Species Value ≥ 0.50 and P ≤ 0.2); the most significant in group 1 were Coccothrinax argentata (IV=0.54) and Pithecellobium keyense (IV=0.43), and most significant in group 2 Coccoloba diversifolia (IV=0.93) and Bursera simaruba (IV=0.82) (Appendix I). On average, the 36 plots within Group 1 were closer to the coastline, ranging between 7-630m (median=118 m, s=129m) and lower in elevation, ranging from 1-18m (median=5m, s=4.8m) (Figures 11). Average species richness for this group is 6 (sd=3.4 species), lower than that of plots in group 2, which are at higher elevations and further 18 away from the coastline (Figure 12). The frequency of sandy plots in Group 1 is 0.86, and were distributed across the three study sites. The 38 plots of group 2 were distributed across the three study sites, with a frequency of 0.82 for plots defined by organic soil. Plots in group 2 were on average further from the coastline and higher in elevation than the coastal plots of group 1. Distance from the coastline for group 2 ranged between 70-2615 m (median=560m, s=714m), and elevation ranged between 1-36m (median=14m, s=8.6m).

Figure 10. Cluster dendrogram depicting clustering of tree plot by species dissimilarity matrix using Ward's method. Branch tips represent individual plots, and are labelled to identify group membership for large Groups 1 and 2.

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Figure 11. Boxplots depicting plot variables of elevation and distance from the coastline of Groups 1 and 2 defined by clustering.

Figure 12. Boxplots depicting basal area (m^2) and species richness for Groups 1 and 2 defined by clustering. Plots in group 1 have a lower density and are less species rich than plots in Group 2.

Nested within the large groups 1 and 2 are seven sub-clusters evident in the dendrogram (PERMANOVA R=0.202, P=0.001 based on 999 permutations), partitioning the two large groups 1 and 2 into smaller clusters; group 1 subdivides into 4 clusters (subgroups 1-4) and group 2 subdivides into 3 clusters (subgroups 5-7) (Figures 13-14). Most significant indicator species (Indicator Species Value ≥0.40 and P ≤ 0.2) for sub- groups were as follows: subroup 1 Casuarina equisetifolia (IV=0.84); subgroup 2 Coccothrinax argentata (IV=0.72); subgroup 3 Zanthoxylum flavum (IV=0.42); subgroup 4 Acacia choriophylla (IV=0.42) and Pithecellobium keyense (IV=0.40); subgroup 5 Coccoloba

20 diversifolia (IV=0.48); subgroup 6 Maytenus buxifolia (IV=0.61), Sideroxylon salicifolium (IV=0.61) and Exothea paniculata (IV=0.44); subgroup 7 Guaiacum sanctum (IV=0.65), Eugenia foetida (IV=0.58), Exostema caribeaum (IV=0.57), Myrcianthes fragrans (IV=0.55), Bursera simaruba (IV=0.46) and Bourreria succulenta (IV=0.45) (Appendix II).

Figure 13. Cluster dendrogram depicting clustering of plot by species dissimilarity matrix using Ward's method. Branch tips represent individual plots, and are labelled to identify group membership for subgroups 1-7.

Figure 14. Ordination diagram showing the distribution of 75 tree plots from Eleuthera (EL), Cat Island (CAT) and Little San Salvador (LSS) on first two dimensions (NMDS1,NMDS2) derived from unconstrained Non-metric Multidimensional Scaling (NMDS; stress = 22.1%). Symbols indicate 7 sub-groups defined by clustering.

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Stands of Casuarina equisetifolia were recorded in 4 plots in the study (3 EL, 1 CAT), and were dominant in coastal sand strand communities at all study sites. Subgroups 3 (18 plots) and 4 (11 plots) of the cluster analysis did not cluster tightly in ordination space, and are representative of plots sampled within Coccothrinax argentata dominated coastal coppice and other communities found at lower elevations and/or closer to the coastline. Subgroup 4 is dominated by species Acacia choriophylla and Pithecellobium keyense, two common species associated with coastal communities, and are more representative of coastal coppice plots found on Cat Island (plots 11 – 2 EL, 11 CAT, 1 LSS). Species richness for this group was 14 species (sd=3.03 species), and was dominated by Coccoloba diversifolia (IV=0.93) and Bursera simaruba (IV=0.82). Sub-groups 5-7 reveal site level variation in interior coppice composition across the three study sites. Sub-group 5B (9 plots: 2 EL, 2 CAT, 5 LSS) most important indicator species was Coccoloba diversifolia, with Sideroxylon americanum, Pseudophoenix sargentii, and Reynosia septentrionalis. Plots within sub-groups 6 and 7 were virtually exclusive to Cat Island (18 plots: 1 EL, 17 CAT) and Eleuthera (12 plots: 12 EL) respectively. The indicator species analysis shows a broad diversity of important indicator species for interior coppice sampled on these two islands. In sub-group 6B, nine species were identified as important for this group, the most important Maytenus buxifolia and Sideroxylon salicifolium, followed by Exothea paniculata, Tabebuia bahamensis and Metopium toxiferum. Subgroup 7, representative of interior coppice composition at Lighthouse Point, had 11 species designated as indicator species for this group. Most important of this group was Guaiacum sanctum, with Eugenia foetida, Exostema caribeaum, Bursera simaruba and Bourreria succulenta as secondary indicator species. The ordination diagrams generated by NMDS for tree and shrub layers (Figures 15- 16) illustrates the variation in plot species composition across the three study sites. There is no distinct clustering of plots according to study site (island), indicating the high degree of shared species assemblages across the three sites. Of the total 124 taxa sampled in all tree and shrub plots, 20% (25 taxa) are shared across all study sites, 27% (34 taxa) are shared between two of three study sites and 48% (59 taxa) were sampled at only one study site (Appendix VI). Species sampled across all study sites are inferred to be common

22 widespread species for the Central Bahama archipelago. Among these are the dominant species of Groups 1 and 2, Coccothrinax argentata, Pithecellobium keyense, Coccoloba diversifolia and Bursera simaruba. Species accumulation curves for each site suggest adequate sampling was conducted on Eleuthera and Cat Island (Figure 17), however further sampling on Little San Salvador is desired as time and conditions on island limited the extent of surveys.

Figure 15.Ordination diagram showing the distribution of 75 tree plots from Eleuthera (EL), Cat Island (CAT) and Little San Salvador (LSS) on first two dimensions derived from unconstrained Non-metric Multidimensional Scaling (NMDS; stress = 22.1%). Symbols indicate island groupings.

Figure 16. Ordination diagram showing the distribution of 75 shrub plots from Eleuthera (EL), Cat Island (CAT) and Little San Salvador (LSS) on first two dimensions derived from unconstrained Non-metric Multidimensional Scaling (NMDS; stress = 22.1%). Symbols indicate island groups.

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Figure 17. Species accumulation curves for tree plots on Eleuthera (31 plots), Cat Island (33 plots) and Little San Salvador (11 plots). Collector method plots species richness as recorded by the observer.

Scatter plot analyses was conducted for the dependent plot variables of density (number of individuals), species richness (number of species) and dominance (basal area [m2]) against the independent plot variables of distance from coastline (meters) and elevation above sea level (meters) (Figure 18). Pearson product-moment correlation coefficient values were calculated and showed a positive correlation for all relationships (Table 2). The strongest positive correlation was observed between plot density and plot distance from the coastline (r=0.68, n=75), and the weakest positive correlation between basal area (m2) distance from coastline (r=0.38, n=75).

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Figure 18. Scatter plot diagrams depicting correlation of number of individuals, species richness and basal area (m2) to plot distance from coastline and plot elevation above sea level. Plots show a stronger positive correlation of variables to distance from coastline than elevation.

Table 2. Pearson product-moment correlation coefficient values (r) for relationships between the dependent variables of plot density, species richness and total basal area with independent variable plot distance from coastline and elevation above sea level. Results indicate a positive correlation between dependent and independent variables, the strongest positive correlation between plot density and distance from coastline.

Density (number of Species Richness Basal Area (m2) individuals) (total number of species) Distance from 0.68 0.56 0.38 coastline (m) Elevation above sea 0.39 0.39 0.52 level (m)

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Shrub and Herb layers The shrub dissimilarity matrix was also analyzed via Ward’s clustering, NMDS and CCA. The NMDS ordination (k=2, stress=22.1%) also identified the vectors elevation (Dim1=0.5205 and Dim 2=0.0745) and distance from coastline (Dim1=0.3628 and Dim2=0.2179) in the ordination space, variance explaining 0.2765 and 0.1791 of variance respectively (Figure 19). CCA did not identify elevation and distance from coastline as influencial vectors in the constrained ordination. Cluster analysis of shrub plots produced two large clusters (PERMANOVA R=0.13, P=0.001 based on 999 permutations). Most significant indicator species (Indicator Species Value ≥ 0.50 and P =0.001) for Group 1 (plots: 15 EL, 13 CAT, 2 LSS) are Coccothrinax argentata (IV=0.44), linearis (IV=0.29) and Gundlachia corymbosa (IV=0.26); group 2 (plots: 16 EL, 20 CAT, 9 LSS) most significant indicator species are Coccoloba diversifolia (IV=0.53), Randia aculeata (IV=0.48) and Eugenia foetida (IV=0.31) (Appendix III).

Figure 19..Ordination diagram showing the distribution of 75 shrub plots from Eleuthera (EL), Cat Island (CAT) and Little San Salvador (LSS) on first two dimensions derived from unconstrained Non-metric Multidimensional Scaling (NMDS; stress = 22%). Symbols indicate 2 groups defined by clustering, ellipses indicate 95% confidence for groups 1 and 2. Vectors show correlation of environmental variables with unconstrained ordination axes.

The herbaceous subplots were nested within the tree plots, effectively sampling herbaceous composition within forested areas. Importance values of herb species were

26 summed for groups identified by Ward clustering of the tree and shrub community data. Most important species (IV≥1.0) were the same for groups 1 and 2 of both tree and shrub layers. Group 1 species were Smilax havanensis (IV=5.45), Jacquemontia havanensis (IV=2.7) and Sporobolis virginicus (IV=1.28); Group 2 species were Smilax havanensis (IV=10), Scleria lithosperma (IV=3.65), Lasciacis divaricata (IV=3.54) and Tillandisa utriculata (IV=1.61).

DISCUSSION CLUSTERING PATTERNS Group 1 of the cluster analysis of tree community data is indicative of plots within the coastal coppices or ‘white-land’ communities across the three study sites. Coastal communities represented by Group 1 plots were dominated by Coccothrinax argentata, akin to the ‘Silver Palm Associations’ of Correll and Correll (1982). The sub-groups nested within Group 1 (subgroups 1-4) reveal the heterogeneity of the coastal communities sampled on this study. Stands of the invasive Casuarina equisetifola (subgroup 1) tend to dominate sandy shore communities in which they have become established. Native to Australia, the species was intentionally planted in mainland Florida as a management strategy for beach erosion, and has subsequently spread throughout most of the islands of the Bahamas (Hammerton 2001). Suppressing native vegetation, and encouraging coastal erosion, the impacts of Casuarina equisetifolia on coastal community health have serious implications for management of coastal areas in The Bahamas (Smith 2010) and is listed as priority species number one for eradication and control in the National Invasive Alien Species Strategy for The Bahamas (Best Commission 2003). Conocarpus erectus and Sabal palmetto of sub-group 3 were recorded in plots at low elevation growing in or along the edge of saltwater and freshwater bodies respectively. communities dominated by Conocarpus erectus were found at Lighthouse Point along the fringes of Big Pond and White Pond, and on the perimeter of hypersaline ponds and lakes on Little San Salvador and Orange Creek. At Lighthouse Point, there were no natural standing or ephemeral freshwater wetlands, and Sabal palmetto was restricted to the perimeter of a man made trench on the study site. Communities of Sabal palms were

27 also found scattered within the coastal coppice of secondary dunes dominated by Zanthoxylum flavum. Zanthoxylum dominated coastal coppice was restricted mostly to higher elevation plots located on the windward side of the Lighthouse peninsula, and did not occur east of the Big Pond. On Little San Salvador, an isolated ephemeral wetland near to the old ruins supported a community of Sabal Palms with herbaceous Phyla nodiflora as its only understory species. The interior landscape of the northern tip of Cat Island features a vast freshwater marshland that is dominated by Sabal palmetto and Cladium jamaicense. Within the Coccothrinax dominated coastal coppice, Acacia and Pithecellobium emerge as secondary dominants and may dominate coppices areas devoid of Coccothrinax argentata. The ‘blackland’ community of Correll and Correll (1982) and the interior dry evergreen formations of Smith and Vankat (1992) are captured by the large Group 2 in the cluster analysis. Coccoloba diversifolia and Bursera simaruba are both common tree and shrub species throughout the archipelago found both in coastal and interior coppice. Coccoloba dominated interior coppice has been documented in The Bahamas by Smith and Vankat (1992) for Andros, Coccoloba-Bursera dominated forests at Clifton Heritage Park on New Providence (Freid EH, unpublished) and most recently dry forests on Abaco and Eleuthera were found to be dominated by Coccoloba diversifolia by Franklin et al (2015). A regional analysis of dry forest composition on Puerto Rico, US Virgin Islands and The Bahamas used ordination and cluster analysis to indicate plots between the three sites which were dominated by Bursera simaruba, Metopium toxiferum and Coccoloba diversifolia (Franklin et al 2015), indicating a common distribution of these dry forest types across the Caribbean region . Historical biogeographical analysis of Bursera simaruba shows a circum-Caribbean distribution for the species, ranging as far north as the Florida peninsula, down into The Bahamas and the Antilles, and throughout north-western South America, Central America and the Yucatan Peninsula (Espinosa et al 2006). Comprising approximately half of the plots from Little San Salvador, this grouping is indicative of a unique interior forest when compared to the Lighthouse and Orange Creek sites. Little San Salvador is predominantly sandy with high ridges spanning the length of the island, hence interior coppice defined by organic substrate is scarce and limited to areas between ridges on the western end of the island. Coccoloba diversifolia and Reynosia septentrionalis are common species across all study sites, however Sideroxylon americanum

28 and Pseudophoenix sargentii were only recorded by plot data for Little San Salvador, with respective relative frequencies of 0.66 and 0.91. The high number of indicator species in this group reflect the diversity of interior coppice composition in The Bahamas by Smith and Vankat (1992) and Franklin et al. (2015). Maytenus and Sideroxylon occur together frequently in the Cat Island coppice, with Exothea and Tabebuia frequently occupying the same community as secondary dominants. Large individuals of Metopium toxiferum, Sideroxylon foetidissimum and latisiliquum also frequent the landscape in areas free from disturbance, dominating the canopy of plant communities represented by subgroup 6. At the Lighthouse point study site, on high ridges overlooking the west side of Big Pond, are extensive stands of Guaiacum sanctum dominating the overstory as large trees and the understory as shrubs and emerging seedlings. In these Guaiacum dominated communities, common secondary dominants are Eugenia, Exostema and Bourreria, which have not grown large to dominate the canopy, but are numerous as single and multi-stem trees in the understory. Large Bursera simaruba trees are scattered within this forest community, although mostly occurring as secondary dominants along with other indicator species identified for this group.

TAXON DISTRIBUTION Woody species recorded across all study sites include the common dry forest species Bursera simaruba, Coccoloba diversifolia, Metopium toxiferum and Coccothrinax argenata (Table 3).. Their ubiquity within the dry forest of the central Bahamas may be attributed to small favored by resident and migratory birds, as well as their ability to successfully colonize both interior and coastal forests. Also common to all study sites is the hardy Tillandsia utriculata, a bromeliad species whose common distribution may also be influenced by its wind dispersed seeds, in addition to the degree and frequency of disturbance of the plant community in which they are found. Sampled and observed areas in Orange Creek did not record Guaiacum sanctum, whereas it was recorded on Eleuthera and Little San Salvador. The hardwood species is known for its use in construction and boat building, and may have been extracted by local builders during The Bahamas’ history of logging. Cat Island plots did however record large mahagoni trees which were

29 absent from sites on Eleuthera and Little San Salvador. An individual of Swietenia mahagoni observed in the interior broad forest of Orange Creek was the largest ever seen by the researcher, measuring 84cm DBH. The largest individuals of Mahogany were located in areas of the forest where large cracks and deep sinkholes were abundant on the karstic forest floor. The survival of such large individuals may be a result of their inaccessibility by loggers unwilling to fell large trees in precarious environments. The endemic Spathelia bahamensis and the parasitic Phoradendron trinervium were also restricted to plots on Cat Island. The land mass at the study site on Cat Island is three time as wide as Lighthouse Point and Little San Salvador, and on average higher in elevation. The larger landmass at the northern end of Cat Island supports extensive freshwater and ephemeral wetlands, with species such as Byrsonima lucida typically encountered on the freshwater islands of New Providence, Abaco, Andros and Grand Bahama.

Table 3. Taxa distribution within sampled plots on Eleuthera, Little San Salvador and Cat Island. Asterisks (*) indicate species endemic to The Bahamas; h=herbaceous layer, s=shrub layer, t=tree layer. See Appendix VI for entire list of species distribution.

Island Little Family Species Cat Eleuthera San Salvador Burseraceae Bursera simaruba s,t t t Coccoloba diversifolia s,t s,t s,t Arecaceae Coccothrinax argenata s,t s,t s,t Metopium toxiferum s,t s,t s,t Bromeliaceae Tillandsia utriculata h h h Poaceae Lasiacis divaricata h h h Sapindaceae Thouinia discolor* s,t s,t - Zygophyllaceae Guaiacum sanctum - s,t s,t Malpighiaceae Byrsonima lucida t - - winterana s,t - - Santalaceae Phoradendron trinervium s - - Rutaceae Spathelia bahamensis* s - - Burseraceae Bursera frenningae* - t - Buxaceae Buxus bahamensis - - t Putranjivaceae Drypetes diversifolia - - t Arecaceae Pseudophoenix sargentii - - s,t

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Plots on Little San Salvador recorded the significant presence of the palm species Pseudophoenix sargentii, whereas the species was absent from plots at Lighthouse Point and Orange Creek. The coastal species Drypetes diversifolia and Buxus bahamensis were also common in coastal forest on Little San Salvador but not recorded at the other study sites. The milkweed Cynanchum bahamense was recorded in plots at Lighthouse Point, an also observed in areas surrounding study sites on Little San Salvador and Cat Island. A second species of the genus Cynanchum, markedly different in form than Cynanchum bahamense and other species described for The Bahama archipelago (Correll and Correll 1982), was observed only on Little San Salvador (Figure 20). N.L. Britton’s account of his expedition to Little San Salvador in 1905 details his observation of a new Metastelma species which he called Metastelma northropiae, now equivalent to West Indian endemic Cynanchum bahamense.

Figure 20. Undescribed species of Cynanchum growing in coastal shrublands on Little San Salvador in The Bahama Archipelago.

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RARE AND ENDEMIC SPECIES A recent revision of endemic species distribution in The Bahamas grouped endemic species into three distinct cluster corresponding to the North, Central and Southern Bahamas (Freid et al. 2014). The three islands in this study are located within the Central island cluster for endemic distributions, and 10 endemic species are restricted to it: Agave indagatorum, Agave millspaughii, Ateleia popenoei, Encyclia withneri, Euphorbia longinsulicola, Harrisia brookii, Matalea correllii, Spathelia bahamensis, Spermacoce felis- insulae and Zamia lucayana (Freid et al. 2014). Of the restricted endemics listed for this central island cluster, only Spathelia bahamensis was recorded within plots on Cat Island. The rare and restricted endemic was observed in the Orange Creek area by Britton during his explorations (1907), in which he compared this ‘most interesting’ species to the “Pride of the Valley” plant of . Spathelia bahamensis is known to occur on Eleuthera as well, but were not encountered at the Lighthouse Point study site. No record or evidence of Spathelia was noted for Little San Salvador. Another Bahamian endemic tree species recorded by plot data was Thouinia discolor (Figure 21), a member of the Sapindaceae family, and was recorded in 7 plots at Lighthouse Point, 10 plots at Orange Creek and no recorded data from Little San Salvador. The Bahamian endemic species Bursera frenningae is a common tree species in the mixed broad leaf coastal forests at Lighthouse Point, and can be found in association with other large, old growth species of Zanthoxylum flavum, Metopium toxiferm, Bursera simaruba and Jaquinia keyensis. Distribution data from Correll and Correll (1982) record its northernmost distribution as Little San Salvador and Cat Island. The species was not recorded in any tree plots at the LSS and CI study sites, however it was observed on Cat Island south of the study site in the settlement of Arthur’s Town. The shrubby Bahamas endemic Varronia bahamensis was recorded growing on all three islands as a common understory shrub in coastal coppices and shrub lands. The low lying endemic shrub Heliotropum nanum was recorded growing in exposed sandy areas at Lighthouse Point and Little San Salvador, and the endemic Waltheria bahamensis (Figure 22) growing in similar exposed areas within the Cat Island study site. Restricted to sandy coastal scrub areas of Little San Salvador and Cat Island was the endemic Agave species Agave braceana.

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Figure 191. Bahamian endemics Thouinia discolor (left) and Waltheria bahamensis (right)..

CLASSIFICATION OF CARIBBEAN PLANT COMMUNITIES The International Classification of Ecological Communities (ICEC) system was adopted by The Nature Conservancy as the most appropriate system of classification for ecological communities in the Caribbean. Adopting a standardized classification system for The Caribbean will facilitate community comparisons across the member islands, allowing researchers and conservation managers to evaluate community patterns of distribution across the region using the same terminology and classification criteria (Areces-Mallea et al. 1999). Within the classification hierarchy of the ICEC (Class-Subclass-Group-Subgroup- Formation-Alliance-Association), the first five levels are defined by vegetation physiognomy whereas the last two levels are determined by species composition or floristics (Grossman et al. 1998). The ‘Class’ level of the hierarchy is based upon the dominant lifeform of the vegetation. This study proposes classifications for forest (overlapping crowns/closed canopy) and woodland (non-overlapping crowns/open canopy) classes. The ‘Subclass’ level is based upon leaf phenology, and is designated as evergreen for dry forests of The Bahama Archipelago i.e. evergreen woody plants comprise at least 75% of the canopy. ‘Group’ level in the hierarchy is based on leaf characters of vegetation communities (broad-leaf, needle-leaf, microphyllous and xeromorphic) and

33 macroclimate type of The Bahama Archipelago (subtropical). The ‘Subgroup’ level divides the ‘Group’ classification into Natural/Semi-natural (natural, semi-natural or modified vegetation) and Cultural (cultural or planted vegetation). Only Natural/Semi-natural vegetation were sampled in this study, as cultivated areas were avoided. Plant associations in a community are the primary units used to classify vegetation, and represent common species assemblages, while alliances can be one to several associations grouped together. The US National Vegetation Classification (USNVC), from which the Caribbean ICEC has evolved, defines an association on the basis of a characteristic range of species composition, diagnostic species occurrence, habitat conditions and physiognomy (Jennings et al. 2009). The alliance is defined by the USNVC as a vegetation unit containing one or more associations, characterized by a range of species composition, habitat conditions, physiognomy and diagnostic species, at least one of which is found in the uppermost stratum of the community (Jennings et al. 2009). Dominant tree species of groups 1 and 2 from the ordination and indicator species analysis were used to classify Alliances across the three study sites, whereas dominant species of subgroups 1-4 and 5-7 were used to define Associations found within respective Alliances.

Proposed Classifications for Sampled Communities on Eleuthera, Cat Island and Little San Salvador Based on ICEC Principles

Order: Tree Dominated Class: I. Closed Tree Canopy (Forest) Subclass: I.A. Evergreen Forest Group: I.A.3. Tropical or Subtropical broad-leaved evergreen forest Subgroup: I.A.3.N Natural/Semi-natural

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Formation: I.A.3.N.a. Lowland tropical or subtropical evergreen forest I.A.3.N.a. Coccothrinax argentata – Reynosia septentrionalis forest Alliance  Coccothrinax argentata– Reynosia septentrionalis – Pithecellobium keyense forest association  Zanthoxylum flavum – Jacquinia keyensis – Casasia clusiifolia forest association  Acacia choriophylla - Pithcellobium keyense - Guapira discolor forest association

I.A.3.N.a Coccoloba diversifolia-Bursera simaruba Forest Alliance  Coccoloba diversifolia-Sideroxylon americanum-Pseudophoenix sargentii forest association  Maytenus buxifolia-Sideroxylon salicifolium forest association  Exothea paniculata-Tabebuia bahamensis-Metopium toxiferum forest association  Guaiacum sanctum forest association  Eugenia foetida-Exostema caribeaum-Bourreria succulenta forest association

Order: Tree Dominated Class: II. Open Tree Canopy (Woodland) Subclass: II.A. Evergreen Woodland Group: II.A.3. Subtropical broad-leaved evergreen woodland Subgroup: I.A.3.N Natural/Semi-natural

Formation: II.A.3.N.a. Lowland subtropical evergreen woodland II.A.3.N.a. Coccothrinax argentata woodland Alliance  Coccothrinax argentata/Erithalis fruticosa woodland association  Coccothrinax argentata/Croton linearis – Gundlachia corymbosa woodland association

II.A.3.N.a. Casuarina equisetifolia woodland Alliance  Casuarina equisetifolia woodland association

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COMMUNITY CLASSIFICATIONS AND ISLAND VEGETATION MAPS Plant community classifications in this study are based on floristic data, and was determined by an analysis of species composition, abundance and distribution within their respective communities. Vegetation maps drawn from satellite imagery uses discernable differences in the vegetation landscape to delineate and label the dominant lifeform or habitat of the plant communities. Classified communities do not always exhibit a spectral difference on the vegetation landscape, as a result, classification units may not match mapping units exactly. The plant alliances dominating the landscape and their respective habitats are more visible compared to the plant associations within the dominant vegetation. The exposed white sandy substrate and silver palm fronds of the Coccothrinax argentata – Reynosia septentrionalis forests provide a recognizable contrast to the Coccoloba diversifolia – Bursera simaruba forest on dark organic soils.

Bannerman Town, Eleuthera (Lighthouse Point) The peninsula at the southernmost point of Bannerman Town is oriented north- south, exposing its eastern shoreline to the windward influence of the Atlantic Ocean (Figure 22). Comparing windward and leeward shorelines around Lighthouse Point reveal a difference in topography and species composition. The windward shoreline features a rolling dune system primarily dominated by a Coccothrinax argentata woodland, transitioning to an older Holocene dune ridge dominated by Coccothrinax argentata- Reynosia septentrionalis coastal forest that extends to the eastern shore of Big Pond. The valleys between the rolling dunes, and the understory of the Coccothrinax woodland support extensive shrublands of Croton linearis, Pithecellobium keyense, Cassia lineata, Solanum bahamense and Cestrum bahamense. The windward coastal forest is mostly free from human disturbance, with occasional fires and severe hurricanes impacting the landscape periodically. The sandy substrate of the windward forests are Holocene in origin, and become partially lithified further from the coastline and at higher elevation, the area lacks thick layers of humus . To the west of Big Pond, the landscape transitions to older, lithified Pleistocene dunes which are higher in elevation than the windward coastal dunes. The interior coppice in these areas are dominated by Coccoloba diversifolia, and Bursera simaruba with clusters of Guaiacum sanctum dominating areas closer to the western edge

36 of Big Pond. Reynosia septentrionalis is ubiquitous throughout the coastal and interior landscape at Lighthouse Point, and has the highest importance value for this study site (IV=2.48). Human disturbance has impacted the leeward forests more than the windward coastal coppice. The area has been surveyed for development and real estate, resulting in boundary lines being bulldozed around tracks of land. Bulldozed lines tend to re-sprout with native herbaceous species such as Croton lucidus and Varronia bahamensis, as well as non-native invasive species such as Leuceana leucocephala. Scattered within the interior coppice are old ruins and rocks walls demarcating boundaries of former plantations and farm lands. The interior coppice west of Big Pond are currently utilized by local residents of Bannerman Town for land crab harvesting.

Figure 22. Vegetation map of Lighthouse Point study site

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Half Moon Cay, Little San Salvador The island of Little San Salvador is approximately 4 square miles in size and the island is oriented east-west, its northern shore facing the Atlantic Ocean and the southern shoreline the Exuma Sound (Figure 23). The western end of the island is located 11 miles from the southern tip of Eleuthera and the eastern end 11 miles from the northern tip of Cat Island. The island’s topography is a predominantly sandy ridgeland, and dominated by extensive Coccoloba diversifolia-Sideroxylon salicifolium-Pseuodophoenix sargentii forests. The most important species recorded for the island, Pseudophoenix sargentii (IV=1.65, freq=0.91), was absent from plots on Lighthouse Point and Orange Creek. Nathanial Lord Britton (1907) provides a written account of exploration of Little San Salvador, and noted the great abundance of ‘Hog Cabbage’ on the island despite its paucity on neighboring Eleuthera and Cat Island, and its extermination from The Florida Keys. The species is commonly used as a food source for domesticated pigs and feral hogs, and a much sought after palm for landscaping due to its striking fronds and bright red , and the relative ease of transplanting wild collected specimens. Sporadic Pseuophoenix were seen in the interior coppice of Cat Island, however never recorded in a plot as a full grown tree. The lack of tree forms and random scattering of seedlings could be indicative of the presence of feral hogs on Cat Island and their absence from Little San Salvador. The lack of specimens from Lighthouse Point could also be indicative of human removal of the species from the landscape. The old limestone ruins built by Cat Island fishermen and farmers in the 1800s were located within the Coccoloba diversifolia-Bursera simaruba dominated forest on organic soil and lithified Pleistocene material. The vegetation community surrounding the ruins tells the tale of its human occupation, with large species of Tamarindus indica and Manilkara zapota dominating the forest canopy, Agave sisilana, Opuntia stricta and Capsicum annuum growing as dominant shrubs understory. Accounts of farming by Britton during his exploration in 1905 named ‘Indian Corn’ and ‘Guinea Corn’ as primary crops being grown, although local Cat Island residents also report Agave sisilana or ‘Sisal” as being cultivated on Little San Salvador as well.

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Figure 23. Vegetation map of Little San Salvador study site.

Orange Creek & Bain Town, Cat Island The study site on Cat Island encompasses a much larger land area than that of Lighthouse Point and Little San Salvador; the area supports a larger diversity of habitats at greater distances from the coastline and at higher elevations above sea level (Figure 24). The study area is oriented north-south similar to that of Lighthouse Point, the windward shoreline features sandy primary dunes interspersed with rocky shorelines, with the leeward facing slopes of dunes dominated by extensive thickets of . Behind the primary and secondary dunes are found multiple wetlands, both freshwater and saltwater, which influence species composition in and around them. The coastal freshwater wetlands are dominated by Sabal palmetto along its borders and Fimbristylis interstincta forming a savanna like community. Evidence of feral hog activity is evident in these areas, as wallowing pits were seen in the mud and nesting sites within large clusters of Cladium jamaicense. A larger expanse of freshwater marshland is located further inland, closer to the western shoreline, and supporting a larger diversity of species but also dominated by Sabal and Cladium. Further north along the eastern shoreline, and repeated within the island’s interior, are a series of saltwater ponds and lakes with varying levels of

39 subterranean connectivity to the surrounding ocean. Hypersaline ponds near to the coastline with no tidal activity were fringed by Conocarpus erectus and Coccoloba uvifera, whereas the larger tidal saltwater lakes nearer to the island’s center were fringed with monocultures of Rhizophora mangle. In the Coccoloba diversifolia-Bursera simaruba forests surrounding these saltwater lakes, high densities of epiphytes occur, with Encyclia altissima, Vanella barbellatus and Tillandsia utriculata dominating the herbaceous layer. Surrounding and elevating above the saltwater lakes are high Pleistocene ridges with dense interior coppice, and thick layers of leaf litter covering the forest floor. This type of forest features karst topography, with large sinkholes, banana holes and cracks in the limestone are clearly evident. These karst features create cooler and more humid microclimates within the forest, facilitating high densities of epiphytes in surrounding forest. Species of note include the bromeliad Tillandsia balbisiana epiphytic to tree trunks and maidenhair fern Adiantum capillus-veneris growing on the walls of shallow caves and sinkholes. Adiantum capillus-veneris was one of two fern species recorded across all sites, both restricted to the Cat Island study site only. The other species of fern, Phlebodia aurea was only seen growing on isolated Sabal palmetto individuals, one located in a Casuarina dominated back-dune habitat with no standing water and the other located within the middle of the interior coppice at a higher elevation. The remnants of Sabal palms near to the coast may be indicative of habitat change by the introduction of Casuarina to the coastal communities. Some areas of the interior coppice landscape have been disturbed by roads, farming and property development, however most of the forest landscape appears relatively undisturbed by humans.

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Figure 24. Vegetation map of Orange Creek study site on Cat Island.

IMPLICATIONS FOR PLANT CONSERVATION IN THE BAHAMA ARCHIPELAGO

Plant conservation in the Bahama Archipelago faces many challenges, one of which is the need for further exploration and documentation of the flora within these islands. This study provides distributional data of existing vegetation at the study sites located on three adjacent islands, and assigns classifications guided by the ICEC vegetation types for The Caribbean. Classification of vegetation communities are working hypotheses, as communities are not stagnant and unchanging, but part of a dynamic system constantly interacting with biotic members of the community as well as abiotic factors of the environment and its specific site or locality. The designation of vegetation types for communities can assist and guide biodiversity efforts in The Bahamas by focusing on community level conservation. Tropical dry forests are under increasing threat globally, and protection of natural communities is an advantageous strategy for protection of flora and fauna within communities, and the habitats that support them.

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The variables of elevation and distance from the coastline were determined to be influential factors on species composition across study sites, revealing a distinction between species within the coastal and interior broad leaf forests sampled on this study. The low lying coastal Coccothrinax argentata-Reynosia septentrionalis forests and Coccothrinax argentata woodlands are under direct threat by coastal development, sand mining and invasive alien species such as Casuarina equisetifolia and Scaevola taccada. The interior Coccoloba diversifolia– Bursera simaruba are also under threat by land development and human induced fires. The history of human extraction from forests of The Bahamas has left its influence on the abundance and distribution of prized hardwoods. The protection of the Guaiacum sanctum forests at Lighthouse Point and large Swietenia mahagoni individuals recorded on Cat Island are important for persistence of these populations at their current locations. The ubiquitous Pseudophoenix sargentii forests of Little San Salvador are also important to regional populations. Opportunities for propagation of native hardwood stocks can facilitate restoration plantings for habitats which have been disturbed or species removed. The potential exists to establish a conversation corridor along these three study sites, as 98% of the land area on Little San Salvador is currently protected, Lighthouse Point is currently being considered for protection and residents of Orange Creek are in support of a national park to stimulate ecotourism opportunities for residents and visitors to the island. Such a conservation corridor comprised of connected protected areas also provides opportunities for future study of the ecological relationships across the three islands. Dispersal of propagative material by wind, water birds may function in maintaining genetic diversity among populations on adjacent islands. A formal genetic study of endemic species and isolated species across the study sites may reveal evidence of genetic drift and speciation. An IUCN Redlist for endangered species is lacking for The Bahamas, and is needed in order to assign conservation priorities to rare species currently under threat of extinction. Climate associated sea level rise will have serious implications for conservation efforts in the Bahamas. The interior broad leaf forests occur at higher elevation and further away from the coastline, and seem to support a larger diversity of species assemblages. When compared to the low lying coastal forests, the interior broad leaf forests may targeted for

42 long term in situ conservation efforts because of its perceived stability in the face of sea level rise and changing weather patterns. The limestone foundation of the islands is porous to ground water, and create the threat of low lying areas becoming infiltrated with seawater, destroying fragile habitats such as permanently flooded and ephemeral wetlands supporting freshwater species. Ex situ conservation of at risk species in low lying areas is needed, and long term monitoring of freshwater communities can elucidate models of how species may be reacting to changes in water salinity. Further exploration and documentation of plant distributions is needed throughout the archipelago, and in addition to classification of communities. This study proposes 2 Alliances and 10 Associations not previously listed by the ICEC for the archipelago. As more classifications are designated to vegetation communities in the Bahama Archipelago, circum-Caribbean comparisons of vegetation distribution become more feasible, thus facilitating and strengthening conservation efforts across the entire Caribbean Biodiversity Hotspot.

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LITERATURE CITED Acevedo-Rodríguez, P. and Strong, M.T., 2012. Catalogue of seed plants of the West Indies. Smithsonian Contributions to Botany, (98), pp.1-1192.

Adams, D.C. and Jackson, J.F., 1997. A phylogenetic analysis of the southern pines (Pinus subsect. Australes Loudon): biogeographical and ecological implications. Proceedings-biological society of washington, 110, pp.681-692.

Anderson, M.J., 2001. A new method for non‐parametric multivariate analysis of variance. Austral Ecology, 26(1), pp.32-46.

Areces-Mallea, A.E., Weakley, A.S., Li, X., Sayre, R.G., Parrish, J.D., Tipton, C.V., Boucher, T. and Panagopoulos, N., 1999. A Guide to Caribbean Vegetation Types. The Nature Conservancy.

Bancroft, G.T. and Bowman, R., 1994. Temporal patterns in diet of nestling white-crowned pigeons: implications for conservation of frugivorous columbids. The Auk, pp.844-852.

BEST Commission, 2003. The national invasive species strategy for the Bahamas. BEST, Nassau, The Bahamas, 40.

Britton, N.L., 1907. Report on the continuation of the botanical exploration of the Bahama Islands. Journal of The New York Botanical Garden, 8, pp.71-81.

Campbell, D.G., 1978. The ephemeral islands: a natural history of the Bahamas. London: Macmillan

Carey, E., Gape, L., Manco, B.N., Hepburn, D., Smith, R.L., Knowles, L., Knowles, D., Daniels, M., Vincent, M.A., Freid, E. and Jestrow, B., 2014. Plant conservation challenges in the Bahama archipelago. The Botanical Review, 80(3), pp.265-282.

Clarke, K.R., 1993. Non‐parametric multivariate analyses of changes in community structure. Australian Journal of Ecology, 18(1), pp.117-143.

Coker, W.C., 1905. Vegetation of the Bahama islands. Macmillan.

Correll, D.S. and Correll, H.B., 1982. Flora of the Bahama archipelago. J. Cramer, Vaduz, Liechtenstien.1692 p.

44

Dufrêne, M. and Legendre, P., 1997. Species assemblages and indicator species: the need for a flexible asymmetrical approach. Ecological monographs, 67(3), pp.345-366.

Espinosa, D., Llorente, J. and Morrone, J.J., 2006. Historical biogeographical patterns of the species of Bursera (Burseraceae) and their taxonomic implications. Journal of Biogeography, 33(11), pp.1945-1958.

Franklin, J., Ripplinger, J., Freid, E.H., Marcano-Vega, H. and Steadman, D.W., 2015. Regional variation in Caribbean dry forest tree species composition. Plant Ecology, 216(6), pp.873-886.

Freid, E., Francisco-Ortega, J. and Jestrow, B., 2014. Endemic seed plants in the Bahamian archipelago. The Botanical Review, 80(3), pp.204-230.

Gleason, H.A. and Cronquist, A., 1964. The natural geography of plants. Columbia University Press.

Grossman, D.H., Faber-Langendoen, D., Weakley, A.S., Anderson, M., Bourgeron, P., Crawford, R., Goodin, K., Landaal, S., Metzler, K., Patterson, K.D. and Pyne, M., 1998. International classification of ecological communities: terrestrial vegetation of the United States. The Nature Conservancy, Arlington, Virginia.

Hammerton, J., 2001. Casuarinas in the Bahamas: a clear and present danger. Bahamas Journal of Science, 9(1), pp.2-14.

Hearty, P.J. and Neumann, A.C., 2001. Rapid sea level and climate change at the close of the Last Interglaciation (MIS 5e): evidence from the Bahama Islands. Quaternary Science Reviews, 20(18), pp.1881-1895.

Jackson, P.W. and Kennedy, K., 2009. The global strategy for plant conservation: a challenge and opportunity for the international community. Trends in Plant Science, 14(11), pp.578-580.

Janzen, D.H., 1988. Tropical dry forests. The Most Endangered Major Tropical Ecosystem, Pp 130-137 in: EO Wilson, Biodiversity. National Academies Press.

Jardón-Barbolla, L., Delgado-Valerio, P., Geada-López, G., Vázquez-Lobo, A. and Piñero, D., 2010. Phylogeography of Pinus subsection Australes in the Caribbean basin. Annals of Botany, 107(2), pp.229- 241.

45

Jennings, M. D., Faber-Langendoen, D., Loucks, O. L., Peet, R. K., & Roberts, D., 2009. Standards for associations and alliances of the US National Vegetation Classification. Ecological Monographs, 79(2), 173-199.

Kass, L.B. and Stephens, L.J., 1990. The trees of the mangrove swamp community of San Salvador island, Bahamas and their" succession" patterns. In Proceedings of the Third Symposium on the Marine and Terrestrial Botany of the Bahamas. Bahamian Field Station, San Salvador, Bahamas (pp. 53-65).

McDowell, T., Volovsek, M. and Manos, P., 2003. Biogeography of Exostema (Rubiaceae) in the Caribbean region in light of molecular phylogenetic analyses. Systematic Botany, 28(2), pp.431-441.

Mittermeier, R.A., Turner, W.R., Larsen, F.W., Brooks, T.M. and Gascon, C., 2011. Global biodiversity conservation: the critical role of hotspots. Biodiversity Hotspots (pp. 3-22). Springer Berlin Heidelberg.

Morrison, L.W., 1997. The insular biogeography of small Bahamian cays. Journal of Ecology, pp.441-454.

Moynihan, J. and Watson, L.E., 2001. Phylogeography, generic allies, and nomenclature of Caribbean endemic genus Neolaugeria (Rubiaceae) based on internal transcribed spacer sequences. International Journal of Plant Sciences, 162(2), pp.393-401.

Negrón-Ortiz, V. and Watson, L.E., 2003. Hypotheses for the colonization of the Caribbean basin by two genera of the Rubiaceae: Erithalis and Ernodea. Systematic Botany, 28(2), pp.442-451.

Northrop, A.R. and Northrop, J.I., 1907. Flora of New Providence and Andros: With an Enumeration of the Plants Collected by John I. Northrop and Alice R. Northrop, in 1890 (Vol. 12, No. 1, pp 1-98). Memoirs of The Torrey Botanical Club.

Oksanen, J., Blanchet, F.G., Kindt, R., Legendre, P., Minchin, P.R., O'Hara, R.B., Simpson, G.L., Solymos, P., Stevens, M.H.H., Wagner, H. and Oksanen, M.J., 2013. Package ‘vegan’. Community ecology package, version, 2(9).

Peet, R.K. and Roberts, D.W., 2013. Classification of natural and semi-natural vegetation. Vegetation Ecology, vol 25, pp.28-70.

Smith, I.K. and Vankat, J.L., 1992. Dry evergreen forest (coppice) communities of North Andros Island, Bahamas. Bulletin of the Torrey Botanical Club, 119(2), pp.181-191.

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Smith, R.L., 2010. Invasive alien plant species of The Bahamas and biodiversity management (Master’s Thesis, Institute of Environmental Sciences, Miami University).

R Development Core Team, 2014. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. 2013. ter Braak, C.J., 1987. The analysis of vegetation-environment relationships by canonical correspondence analysis. (pp. 69-77). In Theory and models in vegetation science. Springer Netherlands.

Trejo‐Torres, J.C. and Ackerman, J.D., 2001. Biogeography of the Antilles based on a parsimony analysis of orchid distributions. Journal of Biogeography, 28(6), pp.775-794.

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APPENDIX I Average importance value (IV), indicator species value (ISV) and probability value (P) of tree species within plot groupings 1 and 2 identified by ordination and cluster analysis.

Tree Species (Family) Average IV ISV P Group 1: 37 plots (17 EL, 14 CAT, 6 LSS) Coccothrinax argentata (Arecaceae) 0.12 0.54 0.001 Pithecellobium keyense (Fabaceae) 0.05 0.43 0.014 Casuarina equisetifolia (Casuarinaceae) 0.10 0.31 0.001 Casasia clusiifolia (Rubiaceae) 0.02 0.30 0.003 Zanthoxylum flavum (Rutaceae) 0.02 0.24 0.001 Jacquinia keyensis (Primulaceae) 0.02 0.23 0.021 Group2: 38 plots (14 EL, 19 CAT, 5 LSS) Coccoloba diversifolia (Polygonaceae) 0.17 0.93 0.001 Bursera simaruba (Burseraceae) 0.12 0.82 0.001 Bourreria succulenta (Boraginaceae) 0.03 0.54 0.001 Metopium toxiferum (Anacardiaceae) 0.08 0.53 0.002 Tabebuia bahamensis (Bignoniaceae) 0.02 0.52 0.001 Maytenus buxifolia (Celastraceae) 0.02 0.50 0.001 Eugenia foetida (Myrtaceae) 0.02 0.47 0.001 Eugenia axillaris (Myrtaceae) 0.01 0.46 0.001 elemifera (Rutaceae) 0.01 0.46 0.001 Guaiacum sanctum (Zygophyllaceae) 0.04 0.40 0.001 (Fabaceae) 0.04 0.39 0.001 Sideroxylon salicifolium () 0.01 0.39 0.001 Exostema caribeaum (Rubiaceae) 0.01 0.38 0.001 Thouinia discolor (Sapindaceae) 0.01 0.28 0.009 Krugiodendron ferreum (Rhamnaceae) 0.00 0.26 0.003 Sideroxylon foetidissimum (Sapotaceae) 0.01 0.26 0.002 Exothea paniculata (Sapindaceae) 0.01 0.21 0.008

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APPENDIX II Average importance value (IV), indicator species value (ISV) and probability value (P) of tree species within subgroups 1A-4A and 5B-7B identified by ordination and cluster analysis.

Tree Species (Family) Average IV ISV P Subgroup 1: 3 plots (2 EL, 1 CAT) Casuarina equisetifolia (Casuarinaceae) 0.65 0.84 0.001 Subgroup 2: 4 plots (3 EL, 1 CAT) Coccothrinax argentata (Arecaceae) 0.49 0.72 0.001 Subgroup 3: 18 plots (9 EL, 4 CAT, 5 LSS) Zanthoxylum flavum (Rutaceae) 0.03 0.42 0.016 Conocarpus erectus (Combretaceae) 0.05 0.28 0.032 Jacquinia keyensis (Primulaceae) 0.04 0.27 0.074 Sabal palmetto (Arecaeae) 0.05 0.21 0.109 Subgroup 4: 11 plots (2 EL, 8 CAT, 1 LSS) Acacia choriophylla (Fabaceae) 1.57 0.42 0.003 Pithecellobium keyense (Fabaceae) 0.89 0.40 0.024 Guapira discolor (Nyctaginaceae) 1.39 0.24 0.13 Subgroup 5: 9 plots (2 EL, 2 CAT, 5 LSS) Coccoloba diversifolia (Polygonaceae) 0.25 0.48 0.001 Sideroxylon americanum (Sapotaceae) 0.02 0.33 0.046 Pseudophoenix sargentii (Arecaceae) 0.05 0.25 0.1 Reynosia septentrionalis (Rhamnaceae) 0.12 0.23 0.19 Subgroup 6: 18 plots (1 EL, 17 CAT) Maytenus buxifolia (Celastraceae) 0.03 0.61 0.003 Sideroxylon salicifolium (Sapotaceae) 0.02 0.61 0.001 Exothea paniculata (Sapindaceae) 0.02 0.44 0.013 Tabebuia bahamensis (Bignoniaceae) 0.03 0.40 0.013 Metopium toxiferum (Anacardiaceae) 0.12 0.37 0.007 Sideroxylon foetidissimum (Sapotaceae) 0.02 0.32 0.04 Krugiodendron ferreum (Rhamnaceae) 0.01 0.31 0.044 Coccoloba swartzii (Polygonaceae) 0.01 0.28 0.028 Lysiloma latisiliquum (Fabaceae) 0.05 0.25 0.083 Subgroup 7: 12 plots (12 EL) Guaiacum sanctum (Zygophyllaceae) 0.08 0.65 0.002 Eugenia foetida (Myrtaceae) 0.04 0.58 0.002 Exostema caribeaum (Rubiaceae) 0.03 0.57 0.001 Myrcianthes fragrans (Myrtaceae) 0.01 0.55 0.007 Bursera simaruba (Burseraceae) 0.16 0.46 0.001 Bourreria succulenta (Boraginaceae) 0.06 0.45 0.001

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Guettarda elliptica (Rubiaceae) 0.01 0.35 0.021 (Rutaceae) 0.01 0.24 0.108 Piscidia piscipula (Fabaceae) 0.01 0.23 0.07 Eugenia axillaris (Myrtaceae) 0.01 0.22 0.141 Thouinia discolor (Sapindaceae) 0.01 0.20 0.165

APPENDIX III Average importance value (IV), indicator species value (ISV) and probability value (P) of shrub species within plot groupings 1 and 2 identified by ordination and cluster analysis.

Shrub Species (Family) Average IV ISV P Group 1 (30 plots: 15 EL, 13 CAT, 2 LSS) Coccothrinax argentata (Arecaceae) 0.096 0.44 0.001 Erithalis fruticosa (Rubiaceae) 0.065 0.41 0.003 Croton linearis (Euphorbiaceae) 0.025 0.29 0.001 Gundlachia corymbosa (Asteraceae) 0.041 0.26 0.001 Lantana involucrata (Verbenaceae) 0.015 0.23 0.003 Salmea petrobioides (Asteraceae) 0.012 0.20 0.008 Turnera ulmifolia (Passifloraceae) 0.019 0.20 0.002 Cassia lineata (Fabaceae) 0.018 0.13 0.024 Tournefortia gnaphalodes (Boraginaceae) 0.019 0.10 0.056 Group 2 (45 plots: 16 EL, 20 CAT, 9 LSS) Eugenia axillaris (Myrtaceae) 0.047 0.56 0.002 Coccoloba diversifolia (Polygonaceae) 0.083 0.53 0.001 Randia aculeata (Rubiaceae) 0.052 0.48 0.001 Acacia choriophylla (Fabaceae) 0.039 0.40 0.004 Eugenia foetida (Myrtaceae) 0.024 0.31 0.001 Amyris elemifera (Rutaceae) 0.010 0.27 0.005 Ateramnus lucidus (Euphorbiaceae) 0.031 0.27 0.006 Chiococca alba (Rubiaceae) 0.011 0.27 0.004 Phyllanthus epiphyllanthus (Euphorbiaceae) 0.022 0.24 0.026 Guaiacum sanctum (Zygophyllaceae) 0.029 0.22 0.008 Tabebuia bahamensis (Bignoniaceae) 0.009 0.22 0.009 Psychotria ligustrifolia (Rubiaceae) 0.011 0.20 0.013 Pseudophoenix sargentii (Arecaceae) 0.020 0.16 0.053 Krugiodendron ferreum (Rhamnaceae) 0.004 0.13 0.07 Maytenus buxifolia (Celastraceae) 0.006 0.13 0.07 Thouinia discolor (Sapindaceae) 0.004 0.13 0.086

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APPENDIX IV - Importance Value totals for tree species sampled on CI, EL, and LSS. Importance values were calculated as the average of relative density, relative dominance and relative frequency.

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APPENDIX V - Importance Value totals for shrub species sampled on CI, EL, and LSS. Importance values were calculated as the average of relative density and relative frequency.

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APPENDIX VI

Checklist of taxa sampled within 75 plots on Cat Island, Eleuthera and Little San Salvador. *= endemic species; h=herb layer, s=shrub layer, t=tree layer.

Island Family Species Abbrev Cat Eleuthera (EL) Little San . (CI) Salvador (LSS) Fabaceae Acacia choriophylla Acacho s,t s,t t Rutaceae Amyris elemifera Amyele s,t s,t t Euphorbiaceae Ateramnus lucidus Ateluc s,t s,t t Boraginaceae Bourerria succulenta Bousuc s,t s,t s,t Burseraceae Bursera simaruba Bursim s,t t t Rubiaceae Casasia clusiifolia Casclu s,t s,t s,t Polygonaceae Coccoloba diversifolia Cocdiv s,t s,t s,t Arecaceae Coccothrinax argenata Cocarg s,t s,t s,t Rubiaceae Erithalis fruticosa Erifru s,t s,t s,t Myrtaceae Eugenia axillaris Eugaxi s,t s,t s,t Nyctaginaceae Guapira discolor Guadis s,t s,t s,t Primulaceae Jacquinia keyensis Jackey t t s,t Poaceae Lasiacis divaricata Lasdiv h h h Fabaceae Lysiloma latisiliquum Lyslat t s,t t Anacardiaceae Metopium toxiferum Mettox s,t s,t s,t Boraginaceae Myriopus volibulis Myrvol h h h Euphorbiaceae Phyllanthus Phyepi s s s epiphyllanthus Fabaceae Pithecellobium keyense Pitkey s,t s,t s,t Rubiaceae Randia aculeata Ranacu s s,t s Rhamnaceae Reynosia septentrionalis Reysep s,t s,t s,t Cyperaceae Scleria lithosperma Scllit h h h Smilax havanensis Smihav h h h Bromeliaceae Tillandsia utriculata Tilutr h h h Rutaceae Zanthoxylum flavum Zanfla t t t

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Family Species Abbrev Cat Eleuthera (EL) Little San . (CI) Salvador (LSS) Casuarinaceae Casuarina equisetifolia Casequ t t s,t

Agavaceae Agave braceana Agabra h - - Apocynaceae Allotoonia agglutinata Allagg h - - Rubiaceae Antirhea myrtifolia Antmyr s,t - - Polygalaceae Badiera oblongata Badobl s - - Malpighiaceae Byrsonima lucida Byrluc t - - Canellaceae Canella winterana Canwin s,t - - Rubiaceae Chiococca parviflora Chipar h - - Cyperaceae Cladium jamaicense Clajam h - - Polygonaceae Coccoloba swartzii Cocswa s,t - - Polygonaceae Coccoloba tenuifolia Cocten s,t - - Malvaceae Corchorus hirsutus Corhir s - - Celastraceae Crossopetalum rhacoma Crorha s - - Euphorbiaceae Croton eluteria Croelu s - - Orchidaceae Encyclia rufa Encruf h - - Orchidaceae Enyclia altissima Enyalt h - - Rubiaceae Ernlit s - - Sapindaceae Exothea paniculata Exopan s,t - - Sapindaceae trifoliata Hyptri s - - Asteraceae villosum Koavil s - - Verbenaceae Lantana bahamensis Lanbah s - - Sapotaceae Manilkara zapota Manzap t - - Malvaceae Melochia tomentosa Meltom s - - Orchidaceae Oeceoclades maculata Oecmac h - - Passifloraceae Passiflora suberosa Passub h - - Apocynaceae Pentalinon luteum Penlut h - - Santalaceae Phoradendron trinervium Photri s - - Myrtaceae Psidium longipes Psilon t - -

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Family Species Abbrev Cat Eleuthera (EL) Little San . (CI) Salvador (LSS) Rubiaceae Psychotria ligustrifolia Psylig s - - Asteraceae Salmea petrobioides Salpet s - - Sapindaceae Serjania diversifolia Serdiv h - - Sapotaceae Sideroxylon Sidfoe s,t - - foetidissimum Rutaceae Spathelia bahamensis* Spabah s - - Meliaceae Swietenia mahagoni Swimah s,t - - Bromeliaceae Tillandsia balbisiana Tilbal h - - Rutaceae Zanthoxylum coriaceum Zancor s,t - -

Boraginaceae Argusia gnaphalodes Arggna - s - Rhamnaceae Auerodendron Auenor - t - northropianum Burseraceae Bursera frenningae* Burfre - t - Fabaceae Calliandra formosa Calfor - s - Lauraceae Cassytha filiformis Casfil - h - Poaceae Cenchrus insertus Cenins - h - Solanaceae Cestrum bahamense Cesbah - s - Euphorbiaceae Croton lucidus Croluc - s - Asclepiadaceae Cynanchum bahamense Cynbah - h - Erythroxylaceae Erythoxylum areolatum Eryare - s,t - Fabaceae Galactia rudolphioides Galrud - h - Nyctaginaceae Guapira obtusata Guaobt - t - Rubiaceae Guettarda krugii Guekru - t - Amaryllidaceae Hymenocallis arenicola Hymare - h - Convolvulaceae Ipomoea microdactyla Ipomic - h - Myrtaceae Myrcianthes fragrans Myrfra - t - Polygalaceae Polygala grandiflora Polgra - t -

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Family Species Abbrev Cat Eleuthera (EL) Little San . (CI) Salvador (LSS) Goodeniaceae Scaevola plumieri Scaplu - s - Celastraceae Schaeferria frutescens Schfru - s,t - Surianaceae Suriana maritima Surmar - t - Apocynaceae Vallesia antillana Valant - s,t - Rutaceae Zanthoxylum fagara Zanfag - s,t -

Asteraceae Ambrosia hispida Ambhis - - h Buxaceae Buxus bahamensis Buxbah - - t Fabaceae Canavalia rosea Canros - - h Putranjivaceae Drypetes diversifolia Drydiv - - t Cactaceae Pilocereus polygonus Pilpol - - h Arecaceae Pseudophoenix sargentii Psesar - - s,t Rubiaceae Rachicallis americana Racame - - s

Fabaceae Cassia lineata Caslin s s - Rubiaceae Chiococca alba Chialb s s - Combretaceae Conocarpus erectus Conere s,t s,t - Euphorbiaceae Croton linearis Crolin s s - Ebenaceae Diospyros crassinervis Diocra s,t s,t - Erythroxylaceae Erythroxylum Eryrot s,t t - rotundifolium Myrtaceae Eugenia foetida Eugfoe s,t s,t - Rubiaceae Exostema caribeaum Exocar s,t s,t - Rubiaceae Guettarda elliptica Gueell s,t t - Rubiaceae Guettarda scabra Guesca s,t s,t - Asteraceae Gundlachia corymbosa Guncor s s - Convolvulaceae Jacquemontia havanensis Jachav h h - Rhamnaceae Krugiodendron ferreum Krufer s,t s,t - Verbenaceae Lantana involucrata Laninv s s -

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Family Species Abbrev Cat Eleuthera (EL) Little San . (CI) Salvador (LSS) Fabaceae Leucaeana leucocephala Leuleu t s,t - spinosa Oplspi s s - Fabaceae Piscidia piscipula Pispis t t - Apocynaceae Plumeria obtusa Pluobt t s,t - Arecaceae Sabal palmetto Sabpal s,t t - Sapotaceae Sideroxylon salicifolium Sidsal s,t t - Solanaceae Solanum bahamense Solbah s s - Poaceae Sporobolus virginicus Spovir h h - Bignoniaceae Tabebuia bahamensis Tabbah s,t s,t - Sapindaceae Thouinia discolor* Thodis s,t s,t - Passifloraceae Turnera ulmifolia Turulm s s - Boraginaceae Varronia bahamensis* Varbah s s -

Agavaceae Agave sisalana Agasis - h h Asteraceae Borrichia arborescens Borarb - s s Zygophyllaceae Guaiacum sanctum Guasan - s,t s,t Malpighiaceae Malpighia polytricha Malpol - s s Sapotaceae Sideroxylon americanum Sidame - t s,t Poaceae Uniola paniculata Unipan - h h

Polygonaceae Coccoloba uvifera Cocuvi s,t - s,t Passifloraceae Passiflora cupraea Pascup h - h

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APPENDIX VII – Table of plot variables recorded for 75 plots at Lighthouse Point (EL), Cat Island (CI) and Little San Salvador (LSS).

Plot No Plot ID Plot Name Island Lat Lon Elev (m) Substrate Dist Coast (m) 1 LH1 LHT2P1 Eleuthera 24.618153° -76.145811° 5 sandy 10 2 LH2 LHT2P2 Eleuthera 24.618156° -76.147772° 9 sandy 180 3 LH3 LHT2P3 Eleuthera 24.617944° -76.151708° 3 muck 138 4 LH4 LHT2P4 Eleuthera 24.618153° -76.155689° 9 organic 119 5 LH5 LHT2P5 Eleuthera 24.618139° -76.157139° 6 organic 80 6 LH6 LHT3P1 Eleuthera 24.622722° -76.145917° 6 sandy 100 7 LH7 LHT4P1 Eleuthera 24.627306° -76.146472° 7 sandy 7 8 LH8 LHT3P2 Eleuthera 24.622694° -76.147972° 13 sandy 310 9 LH9 LHT4P2 Eleuthera 24.627194° -76.148417° 7 sandy 173 10 LH10 LHT4P3 Eleuthera 24.627278° -76.150444° 11 sandy 354 11 LH11 LHT6P1 Eleuthera 24.635444° -76.150167° 5 sandy 8 12 LH12 LHT5P1 Eleuthera 24.630917° -76.149083° 7 sandy 63 13 LH13 LHT4P4 Eleuthera 24.627000° -76.156500° 20 organic 788 14 LH14 LHT3P6 Eleuthera 24.622647° -76.157917° 22 organic 338 15 LH15 LHT3P8 Eleuthera 24.622694° -76.161911° 8 lateritic 64 16 LH16 LHT4P8 Eleuthera 24.627228° -76.164325° 6 organic 440 17 LH17 LHT4P10 Eleuthera 24.627236° -76.168294° 3 sandy 75 18 LH18 LHT5P11 Eleuthera 24.630944° -76.171106° 3 organic 150 19 LH19 LHT5P3 Eleuthera 24.630944° -76.155150° 12 organic 630 20 LH20 LHT5P7 Eleuthera 24.630947° -76.163172° 9 organic 705 21 LH21 LHT6P5 Eleuthera 24.635417° -76.158056° 18 organic 780 22 LH22 LHT5P6 Eleuthera 24.630833° -76.161083° 22 organic 900 23 LH23 LHT7P2 Eleuthera 24.639747° -76.153075° 5 organic 210 24 LH24 LHT7P1 Eleuthera 24.640028° -76.151944° 3 sandy 90 25 LH25 LHP1 Eleuthera 24.630839° -76.156936° 24 organic 811 26 LH26 LHP2 Eleuthera 24.629064° -76.157553° 25 organic 870 27 LH27 LHP3 Eleuthera 24.628692° -76.160811° 23 organic 670 28 LH28 LHP4 Eleuthera 24.632972° -76.155886° 18 organic 650 29 LH29 LHP5 Eleuthera 24.642483° -76.158317° 11 organic 670 30 LH30 LHP6 Eleuthera 24.641869° -76.157994° 12 organic 645 31 LH31 LHP7 Eleuthera 24.642647° -76.152525° 6 sandy 100 32 OC1 OCT1P1 Cat Island 24.693500° -75.709890° 1 sandy 270 33 OC2 OCT2P1 Cat Island 24.690444° -75.720972° 2 sandy 100 34 OC3 OCT2P8 Cat Island 24.690503° -75.696842° 4 sandy 118 35 OC4 OCT2P9 Cat Island 24.690439° -75.695572° 2 sandy 43 36 OC5 OCT3P19 Cat Island 24.685797° -75.684186° 5 sandy 315 37 OC6 OCT3P20 Cat Island 24.685808° -75.682208° 1 lateritic 193 38 OC7 OCT5P1 Cat Island 24.677019° -75.761061° 1 sandy 10

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Plot No Plot ID Plot Name Island Lat Lon Elev (m) Substrate Dist Coast (m) 39 OC8 OCT5P15 Cat Island 24.677083° -75.686000° 16 organic 1212 40 OC9 OCT5P16 Cat Island 24.676872° -75.682103° 1 organic 960 41 OC10 OCT5P2 Cat Island 24.677133° -75.759064° 5 sandy 215 42 OC11 OCT5P5 Cat Island 24.676992° -75.749306° 16 organic 140 43 OC12 OCT5P6 Cat Island 24.677108° -75.745311° 10 organic 96 44 OC13 OCT5P7 Cat Island 24.676933° -75.741314° 22 organic 134 45 OC14 OCT6P1 Cat Island 24.672544° -75.757436° 4 sandy 15 46 OC15 OCT6P15 Cat Island 24.672500° -75.686164° 10 organic 1570 47 OC16 OCT6P2 Cat Island 24.672878° -75.753467° 28 lateritic 365 48 OC17 OCT6P3 Cat Island 24.672756° -75.749494° 36 organic 506 49 OC18 OCT6P4 Cat Island 24.672625° -75.745522° 32 lateritic 614 50 OC19 OCT7P10 Cat Island 24.667878° -75.689892° 14 organic 2190 51 OC20 OCT7P11 Cat Island 24.667653° -75.685967° 9 lateritic 1886 52 OC21 OCT8P1 Cat Island 24.663453° -75.741178° 3 sandy 43 53 OC22 OCT8P10 Cat Island 24.663311° -75.693714° 14 organic 2615 54 OC23 OCT8P11 Cat Island 24.663319° -75.689786° 11 organic 2491 55 OC24 OCT8P2 Cat Island 24.663339° -75.737150° 3 muck 367 56 OC25 OCT8P3 Cat Island 24.663336° -75.733242° 5 organic 100 57 OC26 OCT8P4 Cat Island 24.663336° -75.729336° 5 organic 200 58 OC27 OCT8P9 Cat Island 24.663314° -75.697617° 20 organic 2300 59 OC28 OCT9P1 Cat Island 24.659069° -75.737417° 4 sandy 120 60 OC29 OCT9P2 Cat Island 24.659067° -75.733539° 1 sandy 272 61 OC30 OCT10P1 Cat Island 24.654564° -75.733542° 2 sandy 281 62 OC31 OCT10P8 Cat Island 24.653453° -75.735717° 1 sandy 68 63 OC32 OCT11P1 Cat Island 24.649689° -75.733281° 2 sandy 155 64 OC33 OCT12P1 Cat Island 24.645286° -75.734981° 1 sandy 162

65 LSS1 LSSP7 Little San Salvador 24.583745° -75.948219° 12 organic 130

66 LSS2 LSSP11 Little San Salvador 24.580840° -75.941631° 14 sandy 125 67 LSS3 LSSP10 Little San Salvador 24.576661° -75.923882° 12 sandy 200 68 LSS4 LSSP2 Little San Salvador 24.583506° -75.948977° 14 organic 70 69 LSS5 LSSP8 Little San Salvador 24.585289° -75.949538° 15 organic 270 70 LSS6 LSSP14 Little San Salvador 24.584156° -75.949141° 14 organic 139 71 LSS7 LSSP12 Little San Salvador 24.573339° -75.909867° 13 sandy 206 72 LSS8 LSSP13 Little San Salvador 24.573956° -75.920203° 13 sandy 340 73 LSS9 LSSP6 Little San Salvador 24.581033° -75.934189° 16 sandy 100 74 LSS10 LSSP3 Little San Salvador 24.587219° -75.959631° 18 sandy 80 75 LSS11 LSSP1 Little San Salvador 24.588142° -75.969711° 17 sandy 123

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APPENDIX VIII – R code for summary statistics, ordination, cluster analysis, and indicator species analysis conducted in this study. library(vegan) library(labdsv) library(BiodiversityR) library(ellipse) treecom.data <- read.csv(" ", header=T, row.names=1) treegroups <- read.csv(" ", header=T) treeenv<- read.csv(" ", header=T) treedist<-vegdist(treecom.data, binary=FALSE, method="jaccard") tree.nms=nmds(treedist, k=2,maxit=50) (treefit <- envfit(tree.nms,env,perm=999)) scores(treefit,"vectors") plot(tree.nms) plot(treefit) treeiv.clust.ward<-hclust(treedist,method = "ward.D") plot(treeiv.clust.ward) rect.hclust(treeiv.clust.ward, k=2) treeiv.ward.cut2<-cutree(treeiv.clust.ward,k=2) write.table(treeiv.ward.cut2, "treeiv.ward.cut2.csv", quote=F, row.names=F, sep=",") adonis(treecom.data ~ clusward2, data = treegroups, permutations=999) plot(treeiv.clust.ward) rect.hclust(treeiv.clust.ward, k=7) treeiv.ward.cut7<-cutree(treeiv.clust.ward,k=7) write.table(treeiv.ward.cut7, "treeiv.ward.cut7.csv", quote=F, row.names=F, sep=",") adonis(treecom.data ~ clusward7, data = treegroups, permutations=999) treenms.plot<-ordiplot(tree.nms,type="n") ordisymbol(treenms.plot,y=treegroups,factor="clusward2",rainbow=T, col=treeenv,legend=T) ordiellipse(tree.nms,treegroups$clusward2,kind="sd",conf=0.95) plot(treefit, p.max=0.096) treenms.plot<-ordiplot(tree.nms,type="n") ordisymbol(treenms.plot,y=treegroups,factor="clusward7",rainbow=T, col=treeenv,legend=T)

60 ordiellipse(tree.nms,treegroups$clusward7,kind="sd",conf=0.95) plot(treefit, p.max=0.096) tree.dca<-decorana(treecom.data) summary(tree.dca) (treedcafit <- envfit(tree.dca,treeenv,perm=999)) scores(treedcafit,"vectors") plot(tree.dca) plot(treedcafit) tree.cca<-cca(treecom.data,treeenv) summary(tree.cca) (treeccafit <- envfit(coppice.cca,env,perm=999)) summary(treeccafit) scores(treeccafit,"vectors") plot(tree.cca) plot(treeccafit) treecca.plot<-ordiplot(tree.cca,type="n") ordisymbol(treecca.plot,y=treegroups,factor="clusward2",rainbow=T, col=treeenv,legend=T) ordiellipse(tree.cca,treegroups$clusward2,kind="sd",conf=0.95) plot(treeccafit, p.max=0.018) treenms.plot=ordiplot(tree.nms,type="n") ordisymbol(treenms.plot,y=treegroups,factor="Island",rainbow=T,col=treeenv,legend=T) clusward2_IS <- indval(treecom.data, treeiv.ward.cut2) summary(clusward2_IS, p=0.2, type='short', digits=2, show=p,sort=FALSE, too.many=115) summary(clusward2_IS, p=0.15, type='long', digits=4,sort=FALSE) clusward7_IS <- indval(treecom.data, treeiv.ward.cut7) summary(clusward7_IS, p=0.2, type='short', digits=2, show=p,sort=FALSE, too.many=115) summary(clusward7_IS, p=0.15, type='long', digits=4,sort=FALSE)

shrubcom.data <- read.csv(" ", header=T, row.names=1) shrubgroups <- read.csv(" ", header=T) shrubenv<- read.csv(" ", header=T) shrubdist<-vegdist(shrubcom.data, binary=FALSE, method="jaccard") shrub.nms=nmds(shrubdist, k=2,maxit=50) (shrubfit <- envfit(shrub.nms,env,perm=999)) scores(shrubfit,"vectors")

61 plot(shrub.nms) plot(shrubfit) shrubiv.clust.ward<-hclust(shrubdist,method = "ward.D") plot(shrubiv.clust.ward) rect.hclust(shrubiv.clust.ward, k=2) shrubiv.ward.cut2<-cutree(shrubiv.clust.ward,k=2) write.table(shrubiv.ward.cut2, "shrubiv.ward.cut2.csv", quote=F, row.names=F, sep=",") adonis(shrubcom.data ~ clusward2, data = shrubgroups, permutations=999) shrubnms.plot<-ordiplot(shrub.nms,type="n") ordisymbol(shrubnms.plot,y=shrubgroups,factor="clusward2",rainbow=T, col=shrubenv,legend=T) ordiellipse(shrub.nms,shrubgroups$clusward2,kind="sd",conf=0.95) plot(shrubfit, p.max=0.096) shrub.cca<-cca(shrubcom.data,shrubenv) summary(shrub.cca) (shrubccafit <- envfit(shrub.cca,shrubenv,perm=999)) summary(shrubccafit) scores(shrubccafit,"vectors") plot(shrub.cca) plot(shrubccafit) shrubcca.plot<-ordiplot(shrub.cca,type="n") ordisymbol(shrubcca.plot,y=shrubgroups,factor="clusward2",rainbow=T, col=shrubenv,legend=T) ordiellipse(shrub.cca,shrubgroups$clusward2,kind="sd",conf=0.95) plot(shrubccafit, p.max=0.018) clusward2_IS <- indval(shrubcom.data, shrubiv.ward.cut2) summary(clusward2_IS, p=0.2, type='short', digits=2, show=p,sort=FALSE, too.many=115) summary(clusward2_IS, p=0.15, type='long', digits=4,sort=FALSE) summary(treedens) sd(treedens$EL[1:31]) sd(treedens$CAT[1:33]) sd(treedens$LSS[1:11]) boxplot(treedens) title(main= 'Tree Density', ylab='trees/ha') summary(shrubdens) sd(shrubdens$EL[1:31]) sd(shrubdens$CAT[1:33]) sd(shrubdens$LSS[1:11]) boxplot(shrubdens)

62 title(main='Shrub Density',ylab='number of individuals') summary(herbdens) sd(herbdens$EL[1:31]) sd(herbdens$CAT[1:33]) sd(herbdens$LSS[1:11]) boxplot(herbdens) title(main='Shrub Density', ylab='number of individuals') plot(k2plotchar$sp_rich,k2plotchar$Elev_m) cor(k2plotchar$sp_rich,k2plotchar$Elev_m) plot(k2plotchar$density_ind,k2plotchar$Elev_m) cor(k2plotchar$density_ind,k2plotchar$Elev_m) plot(k2plotchar$BA.m.2,k2plotchar$Elev_m) cor(k2plotchar$BA.m.2,k2plotchar$Elev_m) plot(k2plotchar$sp_rich,k2plotchar$DistCoast_m) cor(k2plotchar$sp_rich,k2plotchar$DistCoast_m) plot(k2plotchar$density_ind,k2plotchar$DistCoast_m) cor(k2plotchar$density_ind,k2plotchar$DistCoast_m) plot(k2plotchar$BA.m.2,k2plotchar$DistCoast_m) cor(k2plotchar$BA.m.2,k2plotchar$DistCoast_m) summary(k2plotchar$Elev_m[1:37]) sd(k2plotchar$Elev_m[1:37]) summary(k2plotchar$Elev_m[38:75]) sd(k2plotchar$Elev_m[38:75]) summary(k2plotchar$DistCoast_m[1:37]) sd(k2plotchar$DistCoast_m[1:37]) summary(k2plotchar$DistCoast_m[38:75]) sd(k2plotchar$DistCoast_m[38:75]) summary(k2plotchar$sp_rich[1:37]) sd(k2plotchar$sp_rich[1:37]) summary(k2plotchar$sp_rich[38:75]) sd(k2plotchar$sp_rich[38:75])

63 summary(islandchar$density_ind[1:31]) sd(islandchar$density_ind[1:31]) summary(islandchar$BA.m.2[1:31]) sd(islandchar$BA.m.2[1:31]) summary(islandchar$sp_rich[1:31]) sd(islandchar$sp_rich[1:31]) summary(islandchar$density_ind[32:64]) sd(islandchar$density_ind[32:64]) summary(islandchar$BA.m.2[32:64]) sd(islandchar$BA.m.2[32:64]) summary(islandchar$sp_rich[32:64]) sd(islandchar$sp_rich[32:64]) summary(islandchar$density_ind[65:75]) sd(islandchar$density_ind[65:75]) summary(islandchar$BA.m.2[65:75]) sd(islandchar$BA.m.2[65:75]) summary(islandchar$sp_rich[65:75]) sd(islandchar$sp_rich[65:75]) summary(shrubspec$V1[1:31]) sd(shrubspec$V1[1:31]) summary(shrubspec$V1[32:64]) sd(shrubspec$V1[32:64]) summary(shrubspec$V1[65:75]) sd(shrubspec$V1[65:75]) plot(k7plotchar$DistCoast_m,k7plotchar$BA.m.2,xlab = "Distance from Coast (m)",ylab ="Basal Area m^2") abline(lm(k7plotchar$BA.m.2~k7plotchar$DistCoast_m),col="red") plot(k2plotchar$DistCoast_m,k2plotchar$BA.m.2,xlab = "Distance from Coast (m)",ylab ="Basal Area m^2") abline(lm(k2plotchar$BA.m.2~k2plotchar$DistCoast_m),col="red") plot(k2plotchar$Elev_m,k2plotchar$DistCoast_m,xlab = "Meters above sea level",ylab ="Meters from coastline") abline(lm(k2plotchar$DistCoast_m~k2plotchar$Elev_m),col="red")

64 plot(k2plotchar$DistCoast_m,k2plotchar$density_ind,xlab = "Distance from Coast (m)",ylab ="Individuals") abline(lm(k2plotchar$density_ind~k2plotchar$DistCoast_m),col="red") plot(k2plotchar$DistCoast_m,k2plotchar$sp_rich,xlab = "Distance from Coast (m)",ylab ="Species richness") abline(lm(k2plotchar$sp_rich~k2plotchar$DistCoast_m),col="red") plot(k2plotchar$Elev_m,k2plotchar$sp_rich,xlab = "Meters above sea level",ylab ="Species Richness") abline(lm(k2plotchar$sp_rich~k2plotchar$Elev_m),col="red") plot(k2plotchar$Elev_m,k2plotchar$BA.m.2,xlab = "Meters above sea level",ylab ="Basal Area m^2") abline(lm(k2plotchar$BA.m.2~k2plotchar$Elev_m),col="red") plot(k2plotchar$Elev_m,k2plotchar$density_ind,xlab = "Meters above sea level",ylab ="Individuals") abline(lm(k2plotchar$density_ind~k2plotchar$Elev_m),col="red") boxplot(k2plotchar$density_ind~k2plotchar$group, main="Average Density Groups 1 & 2", xlab="k2 groups", ylab="Individuals") boxplot(k2plotchar$density_ind~k2plotchar$island, main="Average Density by Island", xlab="Island", ylab="Individuals") boxplot(k2plotchar$Elev_m~k2plotchar$island, main="Plot Elevation by Island", xlab="Island", ylab="meters above sea level") boxplot(k2plotchar$BA.m.2~k2plotchar$island, main="Plot Basal Area by Island", xlab="Island", ylab="BA m^2") boxplot(k2plotchar$sp_rich~k2plotchar$island, main="Plot Species Richness by Island", xlab="Island", ylab="number of species")

65