ATOLL RESEARCH BULLETIN No. 138 THEVERTEBRATEFAUNAANDTHEVEGETATIONOFEASTPLANACAY,BAHAMA ISLANDS by Garre t t C. Clough and George Fulk Issued by THE SMITHSONIAN INSTITUTION Washington, D. C . , U. S. A. February 16, 1971 THE VERTEBRATE FAUNA AND THE VEGETATION OF EAST PLANA CAY, BAHAMA ISLANDS 1 / 2/ by Garrett C. Clough- and George Fulk- GENERAL DESCRIPTION Three expeditions have been made t o East Plana Cay, Bahama Islands, between 1966 and 1968. The primary purpose of these t r i p s was t o study the biology of the Bahaman hut ia , Geocapromys ingrahami, a hystricomorph rodent which ex is t s only on t h i s is land. This paper reports on observations and collections of the l izards , b i rds and plants and gives a general account of t h i s i s land together with a b r i e f note on West Plana Cay. Accounts of the ecology and behavior of the rodent population w i l l appear elsewhere (Clough, 1969 and ms. i n preparation). The dates and par t ic ipants of the three t r i p s were: 1) March 20-24, 1966, G.C. Clough; 2) October 22-28, 1967, G.C . Clough, G . Fulk and Joseph Laterra; 3) March 29-April 4, 1968, G.C. Clough, Robert Howe and John Songdahl. Acknowledgements The f i r s t t r i p was made possible by a grant from the Director 's Fund of the American Museum of Natural History, New York. Transportation was supplied by the Lerner Marine Laboratory, Bimini. The 1967 and 1968 t r i p s were supported by National Science Foundation research grant No. GB-7065 t o G . C . Clough. A i r t ransportation was provided by Chalk's Flying Service, Miami, Florida. The Bahama Ministry of Agriculture and Fisheries kindly granted permission t o make t h i s study. We thank the following spec ia l i s t s who determined many of the specimens: D r . E . Williams and M r . B . Shreve, Harvard University, D r . F. R . Fosberg and D r . M.-H. Sachet, Smithsonian Ins t i t u t i on and D r . R . Hauke, Department of Botany, University of Rhode Island. Present addresses: 1/ Until August 1970. Zoological Laboratory, University of Oslo, - Blindern, Oslo, Norway. 2/ Department of Zoology, University of Rhode Island, Kingston, Rhode - Island 02881, U. S. A. Characterist ics of the Island East Plana Cay i s located a t 22' 23' N. Lat. and 73'30' W . Long. The name French Cays i s sometimes used for t h i s island and i ts neighbor, West Plana Cay, about two miles t o the west. The Plana Cays l i e 82 miles north of Great Inagua, about 26 miles northwest of Mayaguana and 12 miles eas t of Acklin's Island, near the southeast end of the Bahama Islands. The is land i s 1100 acres (465 hectares) i n s i ze . I t i s long and narrow i n shape, about 4.75 miles long and 0.5 mile wide a t i ts widest par t , and i s placed mainly i n a southeasterly-northwesterly direct ion. The southern shore is the leeward shore. I t has a gently sloping beach leading t o a 2,000 foot-wide shallow coral reef . The northern shore receives the main wave action. On tha t s ide the coral reef i s narrower and drops off more steeply. The is land i s composed of coral rock. In a few places exfol ia t ing reef rock extends in to t he sea, and i n a few places 30 t o 40 foot bluffs of eroded coral rock drop steeply t o the beach (Plate 1) . In most places, however, the island i s surrounded by a sand beach which slopes gently from the rocky in t e r io r . The topography i s generally f l a t with gentle slopes reaching a maximum of 60 t o 80 f ee t high. Exposed and sharply eroded coral rock forms about ha l f of the surface. In places t h i s i s a level pavement with some loose slabs of rock (Plate 2). Cracks, crevices and holes up t o three fee t i n diameter are numerous (Plate 3 ) . On the h i l l s i d e s i t e s there are loose blocks of rock and shallow accumulations of s o i l . The western end i s composed of sand dunes. In a few places behind the beach where the rock b luf fs are located there are open caves. One of these, near the middle of the south shore, was large enough f o r us t o enter . We could move about 50 f e e t i n from the entrance, through two rooms about 15 f ee t high and past many small s ide passages. In a few places i n the i n t e r i o r of the is land there are round depressions from 10 t o 15 f ee t deep and 20 t o 30 f ee t i n diameter. One of these could be seen on the a e r i a l photographs t o be f i l l e d with water. On the north s ide of the island, jus t behind the sand beach c res t , the holes and crevices i n t he rock pavement were f i l l e d with c lear sea water, which rose and f e l l with the t i d e . During our three v i s i t s t o the island, which included extensive exploration, we found fresh water only once. That was i n a stagnant puddle three inches deep and a few fee t across located i n a depression i n the rock surface. Climate The climate i n general is warm and dry. The maximum and minimum temperatures we recorded from October 22 t o 28, 1967 were 94OF (34.4OC) and 71?F (21?C). The nearest s t a t i on f o r which we found any meteor- ological records was Great Inagua. Howard and Dunbar (1964) examined r a i n f a l l records kept by the s a l t company there and found the average annual r a i n f a l l was 25 t o 35 inches (635 t o 890 mm). They s t a t e t ha t "there is no regular wet or dry season although somewhat more ra in i s recorded for September, October and November". During our three v i s i t s there were only a few passing t races of precipi ta t ion. Off ic ia l weather s ta t ions are located a t Nassau, 295 miles t o the northwest and a t Grand Turk Island, 170 miles t o the southeast. Data from Walter and Lieth (1967) for these s ta t ions are: Nassau, mean annual temperature of 25OC (77'F) over 47 years and mean annual sum of precipi ta t ion of 1181 nm (47 inches) with a wet season from May through October. Grand Turk Island, mean annual temperature of 26.3"C (79.3'F) over 27 years and mean annual sum of precipi ta t ion of 750 nun (29.5 inches) with a period of high r a i n f a l l i n October and November. LIZARDS Three l i za rd species were collected. These were ident i f ied by D r . Ernst Williams and Mr. B. Shreve of the Museum of Comparative Zoology, Harvard University. The name and catalogue numbers of specimens are l i s t ed below. Leiocephalus greenwayi Barbour & Shreve MCZ 111416-19 Anolis carolinensis brunneus Cope MCZ 111420 Sphaerodactylus cor t icola aporrox Schwartz MCZ 111421 The Leiocephalus, round-tailed l i za rd , was very abundant i n both the rocky and sandy areas. They were diurnal i n ac t iv i ty . The Anolis were seen only occasionally in t h e daytime. They inhabited the palm t rees a t the west end of the is land. One Sphaerodactylus, gecko, was seen. I t was collected a t night from s o i l i n open shrub vegetation. BIRDS Observations of birds were made during October 1967 by G . Fulk and during March-April 1968 by G. C. Clough. An annotated list containing 37 species follows. 4 Procellari idae Puffinus lherminieri, Audubon's Shearwater March. Two or three adults seen each night s i t t i n g a t cave entrances o r f lying near caves. Birds heard ca l l i ng i n f l i g h t over land and water. One adul t found 50 f e e t ins ide large cave i n daytime. Phaethontidae Phaethon lepturus, White-tailed Tropicbird October. A single individual seen once. March. Groups of 10-15 seen every day f lying over reefs . Sulidae Sula leucogaster, Brown Booby - March. One immature b i rd f lying by the is land, one-quarter mile out from beach. Ardeidae Ardea herodias, Great Blue Heron October. Two birds seen together once. Butorides virescens, Green Heron March. One seen perched on dead buttonwood t r e e . Dichromanassa rufescens, Reddish Egret March. Two birds together a t brackish pond a t eas t end. Nyctanassa violacea, Yellow-crowned Night Heron October. One individual seen a t night i n shrubs along shore. Pandionidae Pandion haliaetus, Osprey October. Adult ospreys seen near three nests , a fourth nest was abandoned. One nest on rocky b luf f , another i n top of a buttonwood t ree , another a t top of old s t ee l tower. March. Ospreys seen dai ly . Five birds seen together i n v i c in i ty of nest a t northwest end. Falconidae Falco sp. -0ctober. One large falcon seen f lying over i s land . One small falcon seen three times. Rallidae Rallus longirostr is , Clapper Rail March. One individual seen and captured a t night on north beach terrace. One seen a t dusk walking'through shrub thicket . Haematopodidae Haematopus ostralegus, Oystercatcher October. Single individuals seen twice i n mixed flocks of - shorebirds. March. Two pairs seen along beach. Charadriidae Charadrius wilsonia, Wilson's o r Thick-billed Plover March. One seen. Charadrius h ia t icu la , Northern Ring-billed Plover October. Five seen together with Oystercatcher and Black-bellied - Plovers. Squatarola squatarola, Black-bellied Plover October. Five birds seen i n one flock. Scolopacidae Arenaria interpres, Ruddy Turnstone October. Seen dai ly i n small flocks of three t o s ix . Crocethia alba, Sanderling October. Seen i n small flocks of two t o four. Columbidae Columbigallina passerina, Ground Dove October. Individuals or pa i r s seen frequently along beach terrace and i n open rocky areas. March. Individuals, pa i r s o r groups of four seen along beach terrace. Cuculidae Coccyzus americanus, Yellow-billed Cuckoo October. One seen i n shrub thicket . Trochilidae Unidentified Hummingbirds October. One seen dai ly i n shrub th icke t . One had green head and back, white bel ly and throat , rusty red sides beneath wings, s t ra igh t b i l l , no c res t . Another had b r i l l i a n t rkd chin and throat . March. One hummingbird seen a t brackish pond. Alcedinidae Cer l e alcyon, Belted Kingfisher -11-bctober. Single b i rd seen twice along beach. March. One seen perched on t r e e a t beach edge. Picidae Sphyrapicus varius, Yellow-bellied Sapsucker March. One seen i n buttonwood t ree , was chased by Mockingbird. Mimidae Mimus gundlachii, Bahama Mockingbird October. Three single birds seen i n low shrub thickets i n d i f fe ren t par t s of the island. March. A few males singing from elevated perches i n shrub thickets . Dumetella carolinensis, Catbird October. A few birds seen i n shrubs and buttonwood t r e e s Coerebidae Coereba f laveola, Bananaquit October. Three birds seen i n buttonwood t r e e . March. Three d i f fe ren t males singing i n o r near buttonwood t rees . Parulidae Parula americana, Parula Warbler October. Single birds seen several times i n buttonwood t rees . Dendroica petechia, Yellow Warbler October. Single males seen near t r ee s . March. One male seen foraging i n l i t t e r below buttonwood t ree . Dendroica magnolia, Magnolia Warbler October. Seen twice, feeding i n low shrubs. Dendroica caerulescens, Black-throated Blue Warbler October. Single b i rds seen twice in buttonwood t r e e . Dendroica coronata, Myrtle Warbler October. Seen dai ly , i n groups of up t o f ive birds, foraging i n Ambrosia on beach te r race and i n low shrubs. Attracted t o f resh water a t our camp. Dendroica s t r i a t a , Blackpoll Warbler October. One seen foraging in shrub th icke t . Dendroica palmarum, Palm Warbler October. A few seen i n Ambrosia on beach terrace. March. A few groups of s i x t o e ight birds seen along beach and in t e r io r . Seiurus aurocapillus, Ovenbird October. Single birds seen twice. Wilsonia c i t r ina , Hooded Warbler October. One b i rd seen under buttonwood t r e e . Very tame. Setophaga r u t i c i l l a , Redstart October. Seen four times i n buttonwood t r ee s and shrubs. Fringil l idae Tiar is bicolor, Black-faced Grassquit October. One pa i r seen. March. A few males singing from perches or on the ground. Ammodramus savannarum, Grasshopper Sparrow October. Seen once along beach. VEGETATION Plant Communities Most of the island i s covered with a continuous shrub layer of an even height of three t o four f e e t . The greates t var ia t ion in the vegetation i s found along the beach with i ts zones of changing slope and moisture character is t ics . Eight plant communities could be recognized as containing one o r more dominant species growing on s i t e s distinguishable by s o i l type and topography. 1. Beach slope This is the outer zone of vegetation on the sloping sand beach. I t consists of Tournefortia p a halodes growing as widely spaced bushes about two t o four fee t -&IT-' (Plate 4 ) . 2. Beach c re s t This community grows on the top of t he beach slope. I t occurs i n only a few areas and then i s a few f e e t wide. It consists of sparse growths of Cakile lanceolata and Sophora tomentosa. 3. Sand terrace This i s the f l a t sandy area located behind the beach c r e s t . I t i s up t o 40 f ee t wide i n some places and absent i n other places. I t contains Ambrosia h i s ida primarily with Capraria b i f lo ra i n a few places (Plates 4 an -7- 5 ) 4. Shrub thicket on rock O n r u m p f i a maritima grows i n pure stands. This i s mainly on the higher ground o r s teep slopes where a l l s o i l i s absent. 5. Shrub thicket on sand s o i l Where there is s o i l , mixed communities of shrubs are found. These consist mimari lv of four suecies. Phvllanthus eoiohvllanthus. . , - , - - --, Forestiera segregata, Croton lucidus and Croton l i nea r i s . This -lends in to the Strumpfia community where t he substra te i s pa r t sand and par t rock (Plate 6) . Croton thickets were c l a s s i f i ed by Beard (1949) as a subclimax community of the Windward and Leeward Islands of the southeast Caribbean region. These thickets , composed of various species of Croton, Beard said were "the most impoverished" of any of the plant communities, found on only the "driest , poorest and most degraded s i tes" . 6. Tree grove In a few places small clumps of buttonwood t rees , Conocarpus erectus grew. These are found a t the edge of the Sand te r race o r Brackish water border communities and i n the island i n t e r i o r around exposed rock pavements (Plate 2) . The t r ee s vary from a few f e e t t o about 15 fee t high. A few t a l l e r dead t r e e trunks stood along the south shore a t the beach c r e s t . 7. Palm grove One grove of s i l v e r thatch palm t rees grows near the west end of the island on sandy s o i l . These are about 20 t o 30 f e e t t a l l (Plate 7 ) . 8. Brackish water border A t the edges of the brackish ponds a t the west end there are stands of saltwort, Batis maritima. Brief descriptions of East Plana Cay's vegetation made by D.P. Ingraham i n 1891 (Allen 1891) and by Rabb and Hayden (1957) during t h e i r v i s i t i n 1953 are nearly iden t ica l with those made i n 1966 t o 1968. A s the only difference Ingraham mentions the presence of a few paw-paw t rees , Carica, and says the hu t i a "seemed very fond of the f r u i t of the paw-paw, and even of the body of the t r e e i t s e l f , as I have seen the trunk of t h i s t ree , nearly as large as my body, eaten so nearly off t ha t they could not susta in t h e i r own weight." We found four paw-paw t rees , a l l of which were about four t o s i x inches i n diameter. Perhaps t h i s species has been nearly eliminated from the is land by the hu t ia population. I t was impossible t o discover what other e f fec t s the very high rodent population has exerted on the vegetation over a long period of time. Vascular Flora Plants were collected on the second and t h i r d t r i p s by G. C . Clough. The ident i f icat ions were made by D r . F. R. Fosberg and Dr. M.-H. Sachet of the Smithsonian Ins t i tu t ion . D r . R. Hauke, University of Rhode Island, ass is ted in the determinations. One s e t of specimens is on f i l e with the Smithsonian and another s e t with t he Fairchild Tropical Garden, M i a m i , Florida. In addition t o t he 29 species l i s t e d below there were a t l e a s t two grass species which were not collected o r iden t i f ied . One grass species was observed as a dense patch about 12 f e e t i n diameter i n the i n t e r i o r on sand s o i l and the other grass grew i n a few places i n the Beach crest community. The s i x species of plants known t o be eaten by the hutias are indicated below. Hutia food habi t s were determined by observations of animal ac t iv i ty , examination of plants for signs o f grazing and browsing, and food preference t e s t s of captive animals performed on the island. Palmae Coccothrinax argentata (Jacq.) Bailey Palm called the s i l v e r thatch palm by Rabb and Hayden (1957). These were located near the west end. i n the same h lace where they mew i n . " 1891 ( ident i f ied from photo by R. W . Read). Amaryllidaceae Hymenocallis l i t t o r a l i s (Jacq.) Salisb. A few clumps growing i n Sand terrace community. Ulmaceae Trema lamarckiana (R. and S.) B 1 . Two t o four fee t high, flowering i n March. Common i n Shrub th icke ts on sand s o i l . Moraceae Ficus aurea Nutt. -- Rare, i n t e r i o r of island. Frui t i n October. Batidaceae Batis maritima L. A t edges of brackish ponds growing i n mud. Portulacaceae Portulaca haeos erma Urb. One i-n exposed, bare rocks. Cruciferae Cakile lanceolata (Willd.) Schulz In Beach crest community. Flowering i n October and March. Leguminosae Sophora tomentosa L. In Beach c res t community. Simarubaceae Suriana maritima L . Rare, on Beach c re s t . Prostra te form, two t o three f e e t high, flowering i n March. Euphorbiaceae Phyllanthus epiphyllanthus L. Common, two t o f ive f ee t t a l l . Hutia food. Croton l inear i s Jacq. A b u n d a n t , flowering i n October and March. Croton lucidus L. Abundant, flowering i n March. Hutia food, low preference. Euphorbia mesembryanthemifolia Jacq. In Sand terrace community. Caricaceae Carica papaya L. Rare, a few individuals on the island. Ten t o twelve f ee t high. Cact aceae Cephalocereus sp. Uncommon, four fee t t a l l . Melocactus intor tus (Mill.) Urb. Uncommon, isolated individuals on rocky substrate, i n bloom. Opuntia sp. Uncommon, on Sand te r race . Combretaceae Conocarpus erectus Common, up t o L . 15 f ee t high, t a l l e r dead Oleaceae trunks. Hutia food. Forestiera segregata (Jacq .) Krug and Urb . Abundant. Heavy f r u i t crop in March 1968. Hutia food. Asclepiadaceae Metastelma sp. A vine, growing over Opuntia. Flowering i n October. Convolvulaceae Evolvulus squamosus Brit ton Uncommon, on sand s o i l of Shrub thicket community. Ipomoea repanda Jacq. Vine creeping on ground. Flowers i n October. Boraginaceae Tournefortia gnaphalodes R. B r . Common on Beach slope. Flowering i n March. Hutia food, low preference. Verbenaceae Lantana involucrata L . Uncommon, shrub one t o three feet t a l l . A few on Sand terrace. Flowering i n March. Labiatae Salvia serot ina L. Uncommon. In openings of Shrub th icke ts on sandy s o i l . Six t o ten inches t a l l . Scrophulariaceae Capraria b i f lo ra L. Uncommon. In Sand terrace March, most i n seed then. Antirrhoea myrt i fol ia (Griseb.) Uncommon. In Sand terrace inches t a l l . Flowering i n community. A few flowers l e f t i n Six t o ten inches t a l l . Rubiaceae Urb . community. Isolated plants s i x October and March. Strumpfia maritima Jacq. Abundant. Flowering i n October. Hutia food, top preference. Compositae Ambrosia hispida Pursh Abundant in Sand te r race community. NOTES ON WEST PLANA CAY In March 1966 G. C. Clough v i s i t e d West Plana Cay, going ashore a t three different points on the west and northwest s ides . A t o t a l of three hours were spent on shore observation tours . In 1967 and 1968 ae r i a l observations were made by expedition members as they passed over the island i n a low-flying airplane. West Plana Cay i s qui te d i f f e r en t from i t s neighbor. In shape it is more nearly round; i n s i z e it i s nearly the same. There appears t o be very l i t t l e exposed coral rock on the island and much more s o i l . The vegetation is thicker and higher in many places. Grasses are common. A t the northwest point t he remains of an old v i l l age made of stone huts are found. Nearby is a new v i l lage of wood and thatch homes which are used temporarily every summer by residents of Acklin's and Crooked Islands. Coconut palm t r e e s and garden p lo t s were present around the old and new v i l lages . Two shallow wells which contained some fresh water had been dug near t he new v i l lage . One object which might possibly have been a very old fecal pe l l e t of a hu t ia was found along the beach. Otherwise, absolutely no signs of hut ias were found on West Plana Cay. REFERENCES Allen, J. A. 1891. Description of a new species of Capromys from the Plana Cays, Bahamas. Bull. h e r . MLIS. Nat. H i s t . 3: 329-336. Beard, J. S. 1949. The natural vegetation of the Windward and Leeward Islands. Oxford Forestry Memoirs. No. 21. Clough, G. C. 1969. The Bahaman hut ia : a rodent refound. Oryx 10 (2): 106-108. ---------- i n m s . High rodent productivity in a semi-arid, t rop ica l is land ecosystem, and, Ecology and behaviour of the Bahaman hutia, Geocapromys ingrahami. Howard, R. A. and Dunbar, H. 1964. Additions t o the f l o r a of Inagua, the Bahamas. Rhodora 66: 6-15. Rabb, G. B. and Hayden, E . B . , Jr. 1957. The Van Voast--American Museum of Natural History Bahama Islands Expedition. h e r . Mus. Novitates NO. 1836: 1-53. Walter, H. and Lieth, H. 1967. Klimadiagramm. Weltat las. Lief 3. Gustav Fischer Verlag. Jena. I Plate 1. East Plana Cay. Bluff on northern s ide with osprey nest on top of rock a t l e f t . Plate 2 . East Plana Cay. Flat rock pavement with broken s labs and crevices. Low Conocarpus t r ee s and Phyllanthus shrubs. P l a t e 3 . East Plana Cay. Eroded hole i n rocky i n t e r i o r which served as d iu rna l s h e l t e r f o r t h e rodents , Geocapromys ingrahami. Phyllanthus shrubs. P l a t e 4. East Plana Cay. South shore with t h e Beach slope community of Tournefor t ia i n cen te r . The Sand t e r r a c e community with . < Ambrosia begins a t t h e r i g h t . One clump o f Conocarpus i n . . center . Pla te 5 . East Plana Cay. Aer ia l photo of south shore. Beginning from t h e shore th ree p l a n t communities a r e v i s i b l e : Beach s lope , Sand t e r r a c e and Shmb t h i c k e t on sand s o i l . The Beach c r e s t community i s t o o narrow t o be v i s i b l e . P la t e 6. East Plana Cay. I n t e r i o r view of Shrub t h i c k e t on sand s o i l which contains t h e four main spec ies . Strumpfia e n t e r s i n t h e background. P l a t e 7 . East Plana Cay, nea r western t i p . The grove of s i l v e r tha tch palms.