Post on 27-Apr-2020
NO. 241 March 1980
ATOLL RESEARCH BULLETIN
241. Geography and Ecology of Little Cayman Ediled by D.R. Sroddm and M.E.C. GiglioLi
Issued by THE SMITHSONIAN INSTlTUTION Washington, D.C., U.S.A.
ACKNOWLEDGEMENT
The A t o l l Resea rch B u l l e t i n i s i s s u e d by t h e Smi thson ian I n s t i t u t i o n , a s a p a r t of i t s a c t i v i t y i n t r o p i c a l b i o l o g y , t o p l a c e on r e c o r d i n f o r m a t i o n on t h e b i o t a of t r o p i c a l i s l a n d s and r e e f s , and on t h e envi ronment t h a t s u p p o r t s t h e b i o t a . The B u l l e t i n i s s u p p o r t e d by t h e N a t i o n a l Museum of N a t u r a l H i s t o r y and is produced and d i s t r i b u t e d by t h e Smi thson ian P r e s s . The e d i t i n g i s done by members of t h e Museum s t a f f and by D r . D. R. S t o d d a r t ,
The B u l l e t i n was founded and t h e f i r s t 117 numbers i s s u e d by t h e P a c i f i c S c i e n c e Board, N a t i o n a l Academy o f S c i e n c e s , w i t h f i n a n c i a l s u p p o r t from t h e O f f i c e of Naval Research . Its p a g e s were l a r g e l y d e v o t e d t o r e p o r t s r e s u l t i n g from t h e P a c i f i c S c i e n c e Board ' s C o r a l A t o l l Program,
The s o l e r e s p o n s i b i l i t y f o r a l l s t a t e m e n t s made by a u t h o r s of p a p e r s i n t h e A t o l l Research B u l l e t i n r e s t s w i t h them, and s t a t e m e n t s made i n t h e B u l l e t i n do n o t n e c e s s a r i l y r e p r e s e n t t h e v i ews of t h e Smi thson ian n o r t h o s e of t h e e d i t o r s of t h e B u l l e t i n .
IT, R, h'osberg I a n G , MacIn ty re Me-Ti. S a c h e t
Smi thson ian ins tiru t i o n Vash ing ton , D. C. 2G560
D. R, S t o d d a r t
Department of Geography U n i v e r s i t y of Cambridge Downing P l a c e Cambridge, England
ATOLL RESEARCH BULLETIN
No. 241
OELOCY OF LIT
@:clltd 1n D.R. 3 t o t l r i a n t anti 11.E.(:. d;ielioli
P l a t e 1. The south c o a s t of L i t t l e Cayman, from t h e -
southeas t ; noon cumulus extending along t h e l eng th of t he i s l a n d
CONTRIBUTORS
R.R. ASKEW Department of Zoology, The Universi ty , Manchester, England
A.W. DIAMOND Department of Zoology, Univers i ty of Nairobi , Nairobi , Kenya
M. E. C. G I G L I O L I Mosquito Research and Control Uni t , Grand Cayman, Cayman I s l ands , West Ind ie s
M.V. HOUNSOME The Manchester Museum, Manchester, England
G.W, POTTS Marine Bio logica l Associat ion of t h e U . K . , The Marine Laboratory, Plymouth, England
G.R. PROCTOR Natural History Divis ion, I n s t i t u t e of Jamaica, Kingston, Jamaica
D.R. STODDART Department of Geography, Universi ty of Cambridge, Cambridge, England
C . WOODROFFE Department of Geography, Univers i ty of S h e f f i e l d , She f f i e ld , England
iii
CONTENTS
S c i e n t i f i c survey of L i t t l e C a y m a n
D.R. Stoddart
G e o l o g y and g e o m o r p h o l o g y of L i t t l e C a y m a n
D.R. Stoddart
M a n g r o v e s e d i m e n t s of L i t t l e C a y m a n
C . Woodroffe
T h e zonat ion of rocky l i t t o r a l areas around L i t - t l e C a y m a n
T h e l i t t o r a l f ishes of L i t t l e C a y m a n
G. W . P o t t s
V e g e t a t i o n of L i t t l e C a y m a n
D . R . Stoddar t
C h e c k l i s t of the p lan t s of L i t t l e C a y m a n
G.R. P r o c t o r
'l'errestrial f a u n a [ e x c l u d i ~ l q b i r d s and i n s e c t s ) or' L i t t l e C a ynan
C e r i o n I r m a ( M a y n a r d ) (Molluscs: C e r i o ~ l i d a e 1 or? L i t t l e C a y m a n
M.V. H o u n s o m e and R . R . A s k e w
T h e insect fauna of L i t t l e C a y m a n
R . R . A s k e w
T h e O d o n a t a of t h e C a y m a n Is lands
R . R . A s k e w
T h e b u t t e r f l y ( L e p i d o p t e r a , R h o p a l o c e r a ) fauna of the C a y m a n I s lands
Page 1
11
1 7
2 3
4 3
5 3
7 1
8 1
91
9 7
115
R.R. A s k e w
13. Hawkmoths (Lepidoptera, Sphingidae) of L i t t l e Cayman 139
R. R . Askew
14. Ecology and species turnover of the b i r d s of L i t t l e Cayman 141
A.W. Diamond
15. The Red-footed Booby colony on L i t t l e Cayman: s i z e , s t r u c t u r e and s igni f icance 165
A.W. Diamond
16. L i t t l e Cayman: ecology and s igni f icance
D.R. Stoddart
LIST OF PLATES
1. The south c o a s t of L i t t l e Cayman, from the southeas t ; noon cumulus extending along the length of the i s l a n d F r o n t i s p i e c e
Fo l lowing page 16
2. Sparrowhawk H i l l from the no r th c o a s t beach r idge
3. Limestone r i d g e in land of t h e c o a s t a l s a l t pond a t Charles Bight
4. Limestone r idge and c o a s t a l sand f l a t and s a l t pond a t Mary's Bay
5. Dissected sur face on the Bluff Limestone (6032 1763) ; che s i d a s of t he frame a r e 50 cm long
6. De ta i l of sur face d i s sec t ion on Bluff Limestone
7. Large dol ine i n Bluff Limestone (6028 1778)
8. Cave speleothems revealed by roof co l l apse (6003 1781)
9. Bluff coas t a t East Poin t
10. Ironshore platform west of Calabash Spot
11. D i p l o r i a colcmiss i n coas t a l Ironshore a-t S a l t Rocks
I%, Strombus she i l s I n c o a s ~ a l Ironshore a t S a l t Rocks
13. Ironshore deposiLs on the landward margins of t h e Blossom Vi l lage lagoon
14. Potholes i n the Ironshore sur face a t S a l t Rocks
15. Bedded c a l c a r e n i t e s overlying r ee f f a c i e s i n t h e Ironshore a t S a l t Rocks
16. De ta i l of t h e bedded c a l c a r e n i t e s a t S a l t Rocks
17. Beach r idge e a s t of P i r a t e ' s Poin t
18. Beach r idge a t Calabash Poin t
19. Sand beach r idge with juveni le C a s u a r i n a i n Wearis Bay
2 0 . Storm wash-over cobbles nor th of East Rocky Poin t , Blossom
Bay
2 1 . Hurricane-deposited storm blocks on the Ironshore platform south of t h e a i r s t r i p (5957 1737)
F o l l o w i n g page 42
Preston Bay showing the exposed l i t t o r a l rocks and sandybeach above them
West End Rocks with a l a r g e l i t t o r a l rock pool i n t he f oreg.-ound
E c k i r l i n u s n o d i a l o s u s i n c r ev ices wi-th L i t t o r i n a z i c z a c on the upper m i d l i t t o r a l region of Pres-ton Bay
T e c t a r i i a s rnuz- icatus (arrowed) among the leaves of ,Sesuvium p o r t u l a c a s t r u m a.t West End Rocks
N e r i t a p e l o r o n t a and N. t e s s e l l a t a on rocks a t t he m i d l i t t o r a l zone, E c b i n i n u s n o d u l o s u s and L i t t o r i n a z i c z a c a r e p re sen t i n c r ev ices
T u r b i n a r i a t u r b i n a t a , P a d i n a s a n c t a e - c r u c i s and D i c t y o t a sp. i n t he lower m i d l i t t o r a l zone a t West End Rocks
East End showing t h e s t eep and deeply d i s s e c t e d l i t t o r a l region
T e c t a r i u s r n u r i c a t u s i n l a r g e numbers i n -the s u p r a l i t t o r a l f r i n g e a t Eas t End
~ c a r ~ t h o p l e u r a i j r a n u l a t a i n shallow rock pools i n t he lower m i d l i t t o r a l zone
Rock pool a t West End Rocks showing P u p e r i t a pupa and L i t t o r i n a m e s p i l l u r n sca t t e r ed over the bottom of the pool
v i i
35. P u p e r i t a pupa gathered on a rocky pinnacle within a rock pool
36. Diadema a n t i l l a r u m i n a low t i d e l e v e l rock pool a t Preston
Bay
F o l l o w i n g page 7 0
37. Dry evergreen f o r e s t south of Sparrowhawk H i l l ; note t h e human f i g u r e i n the c e n t r e of t h e p i c t u r e (6003 1775)
38. Dry evergreen woodland in land from Jackson's Bay (5977 1768)
39. Dry evergreen t h i c k e t on Sparrowhawk H i l l (6004 1780)
40. Open dry evergreen t h i c k e t on the northern s lopes of Sparrowhawk H i l l (6003 1781)
41. A c r o s t i c h u m aureum i n l imestone so lu t ion holes nor th of Blossom Vi l lage (5953 1750)
42. Wind-sheared c o a s t a l hedge of Cocco loba w i f e r a , Owen Is land
4 Pioneer H y m e n o c a l l i s l i t o r e a and o ther herbaceocs p ioneers a t Sandy Point
44. Decapitated coconuts on t h e c o a s t a l beach r idge near West Point
45. Coconut p l a n t a t i o n with many dead t r e e s on Owen Is land
46. Low R h i z o p h o r a i n the c o a s t a l lagoon e a s t of Diggary 's Poin t (6030 1773)
47, T a l l A v i c e n n i a woodland i n Tarpon Lake
4 8 , ' i 'a i l l i i l i zophora ;.ioociland i n Tarpon Lake
49- I n t e r i o r of t a l l Ri i i zophora woodland a t Tarpon Lake
50, Dwarf in land Rhi zophora i n an i n t e r i o r depression (5975 17613
51. Inland S e s u v i u ~ n marsh with open pools a t t h e e a s t end of the i s l a n d (6074 1795)
F o l l o w i n g page 96
52. The s i t e on the t rans- i s land t r ack no r th of Blosson Vi l lage where l i v i n g Cerion n a n u s was found. The s n a i l s were l i v i n g on shrubs of E v o l v u l u s a r b u s c u l a here seen growing on t h e pa th
v i i i
53 . C e r i o n nanus and young C.pannosum on a s ing le p lan t of E v o l v u l u s a r b u s c u l a . Inse t : a l i v i n g specimen of C . nanus
54. Six s h e l l s of C . nanus with an example of C . pannosum f o r comparison ( t o the same s c a l e ) . Four typ ica l s h e l l s a r e shown together with two examples of extremes i n length/height r a t i o
LIST OF FIGURES
F o l l o w i n g page 10
1. Location of t he Cayman I s l ands
2 . Iilonth1.y r a in fa l l . a t L i t t l e Cayman
F o l l o w i n g page 1 6
3. Topography of L i t t l e Cayman, based on the Direc tora te of Overseas Surveys l:25,000 map (1965)
4 . Topographic t r a v e r s e s A-F: f o r l oca t ions see Figure 3
5. Geology and h a b i t a t s of L i t t l e Cayman
6. Topographic p r o f i l e s a t S a l t Rocks
7. Beach r idge and c l i f f e d coas t p r o f i l e s : f o r l o c a t i o n s see Figure 3
8. Size composition of beach sediments
F o l l o w i n g page 22
9 , Topographic p r o f i l e of in land dwarf Rhi zophora scrub
LO, Topographic p r o f 1 I . e ~ of A, Fhi zophora woodland a t Tarpon Lake, I3, North coas t salt-pond Rhizopi loza woodland near Sparrowhawk Hil. l
11, Map of L i t t l e Cayman showing the main coas t a l sampling a reas
1 2 . Graphs of the d a i l y t i d a l range during t h e per iod of t h e expedit ion together with hourly t i d a l he ights on a neap t i d e and a spr ing t i d e . The da ta were provided by D r . K. George and based on f i g u r e s obtained from A d m i r a l t y T i d e T a b l e s , Vol. 11, 1975
P r o f i l e of t h e shore a t Preston Bay with an i n d i c a t i o n of t h e v e r t i c a l zonat ion of t h e l i t t o r a l spec ies . The i n s e t shows how on t h e upper shore some spec i e s remain i n pools ( N e r i t a v e r s i c o l o r ) , i n mois t c r ev ices ( L i t t o r i n a z i c z a c ) , and on the open rock ( E c h i n i n u s n o d u l o s u s and N o d i l i t t o r i n a t u b e r c u l a t a ) . L i t t o r i n a z i c z a c r e f e r s t o t he appropr ia te spec i e s of t he L. z i c z a c "complex" (Borkowski and Borkowski, 1969) found i n an a rea , and does so i n subsequent f i g u r e s
Histograms i n d i c a t i n g t h e d i s t r i b u t i o n of four spec i e s of gastropod along t h e j e t t y a t Preston Bay. Black columns r ep resen t t h e e a s t s i d e of t h e j e t t y and s t i p p l e d columns t h e west s i d e
P r o f i l e of t h e shore a t West End Rocks wi th an i n d i c a t i o n of t h e v e r t i c a l zonat ion of t h e common l i t t o r a l spec i e s
P r o f i l e of t h e shore a t J ackson ' s Bay Poin t i n d i c a t i n g t h e v e r t i c a l zonation of t h e common l i t t o r a l spec i e s . The d o d i e occurrence of some l i t t o r i n i d s and n e r i t e s i s a r e s u l t of t h e i r presence on a l a r g e boulder found j u s t below MLWM
The d i s t r i b u t i o n of rno l lu sca~~ zones around. a bou.ld.er a t Jackson ' s Bay Poin t ( see Figure 1 6 ) . It should be not iced t h a t t h e r e i s a d i f f e r e n c e i n t he e x t e n t of t h e zones on the seaward and landward s i d e s of the boulder
P r o f i l e of t h e shore a t t h e Eas t End i n d i c a t i n g t h e d i s t r i b u t i o n of t he common l i t t o r a l spec ies
Out l ines and o r i e n t a t i o n s of l i t t o r a l rock pools a t West End Rocks and Jackson ' s Bay. Pools A , B and C occurred a t approximately mid-tide l e v e l s and D, E and F a t low t i d e l e v e l s . A diagrazmacic secclon X-Y of pool A i s given with the d i s t r i b u ~ i o n of some of t h e common rock pool i n v e r t e b r a t e s
t70110winy page 52
20. Dlagran! of ( a ) Splash Zone and. (b) S u y e Zone ; > O O ~ S wi th t h e i r t y p l c a i inhabitants: 1, Eucinostoiilus a r q e n c e u s ; 2 . B a t h y g o b i u s s o p o r a t o r ; 3. Hbudefduf s a x a t i l i s ; 4. L u t j a n u s apodus; 5. Gerres c i n e r e u s ; 6. Tomicodon f a s c i a t u s ; 7 . A d i o r y x v e x i l l a r i u s ; 8 . Eupomacentrus l e u c o s t i c t u s ; 9. P u p e r i t a pupa; 10. A c e t a b u l a r i a s a n c t a e - c r u c i s ; 11. Thalassoma b i f a s c i a t u m ; 1 2 . Diadema a n t i l l a r u m ; 13. C a n t h i q a s t e r r o s t r a t a ; 14. L i t t o r i n a mespil lurn; 15. Echidna c a t e n a t a
Fo l lowing page 70
2 1 . Habi ta t s and geology of L i t t l e Cayman
2 2 . Vegetation and topography of Owen I s l and
Fol lowing page 90
23. Number of spec ie s (o ther than i n s e c t s and b i r d s ) and sampling s i t e s , L i t t l e Cayman, 1975
Fol lowing page 11 4
24. The progression of i n s e c t spec ies recorded on L i t t l e Cayman by da tes . F u l l c i r c l e s s i g n i f y d a t e s on which ha l f t he f i n a l t o t a l of spec ie s i n each group were found. The l i g h t t r a p was f i r s t operated on 14 J u l y , t he Malaise t r a p on 16 J u l y , and the main c e n t r a l f o r e s t c o l l e c t i o n s were made on 28 July
Fol lowing page 138
25. The r e l a t i o n s h i p between t h e numbers of b u t t e r f l y spec ies and t h e a r e a s (sq km on a logari thmic s c a l e ) of Cuba, Hispa.niola, Puerto Rico, Jamaica, and the Cayman I s l ands (r = 0.98)
26 . Map of L i t t l e Cayman showing l o c a l i t i e s mentioned i n t h e t e x t and the s i t u a t i o n of t h e t r a n s e c t s
2 7 . Associat ions between t h e b u t t e r f l y faunas of t h e Greater A n t i l l e s based upon mean va lues of Co le ' s Coef f i c i en t of Associat ion. The s c a l e r ep resen t s p o s i t i v e va lues of Co le ' s Coef f i c i en t
28. Numbers of b u t t e r f l i e s s igh ted a t hourly i n t e r v a . 1 ~ ( l o c a l t ime) during t r a n s e c t s on t h r e e days a t P i r a t e ' s P o i n t , L i t t l e Cayman. Shade temperatures a r e shown above. For each hour t h e columns r ep resen t (from l e f t t o r i g h t ) 16, 1 7 and 20 J u l y
30, Map showing locatl.on af th.e ma-is! h a b i t a t s on 1~it.t.l.e C'ai~mari,
place names, and c u t pa ths used a s t r a i l s ec t s
31. Feeding he igh t s of four insec t ivorous passe r ines on L i t t l e Cay~nan: ( a ) Caribbean Elaenia; (b) Bananaquit; ( c ) V i t e l l i n e Warbler; (d) Yellow Warbler. Ordinate: he ight i n i n t e r v a l s of 2 m ( G r = ground). Abscissa: percentage of feeding observa t ions i n each he ight c l a s s . White a reas ( r i g h t of 0 % ) : feeds on f r u i t (Elaenia, V i t e l l i n e Warbler) o r nec ta r (Bananaquit, Yellow Warbler) . Black a r e a s ( l e f t of 0%) : feeds on i n s e c t s . For sample s i z e s , s ee Table 29
x i i
Fol lowing page 170
32. Out l ine map of L i t t l e Cayman, showing t h e l o c a t i o n o f t h e booby colony and d e t a i l of t h e colony a r e a . Numerals r e f e r t o prev ious s i t e s of t h e colony (see t e x t ) . L e t t e r s r e p r e s e n t s e c t i o n s of t h e p r e s e n t c o l o n y used i n t h e census (see Table 30) . Arrows r ep re sen t main f l i g h t l i n e s
33. Diurnal v a r i a t i o n i n number of boobies p r e s e n t i n t h e sample a r e a of t h e colony
Fol lowing page 180
34. Recommended marine and t e r r e s t r i a l conservat ion a r e a s , L i t t l e Cayman
x i i i
LIST OF TABLES
R a i n f a l l records a t L i t t l e Cayman. Data by cour t e s ty of the Mosquito Research and Control Unit, Grand Cayman
Publ ica t ions on i n s e c t s of L i t t l e Cayman a r i s i n g from t h e Oxford Universi ty Expedition t o the Cayman I s l ands i n 1938
Size d i s t r i b u t i o n of t he common l i t t o r a l Mollusca around L i t t l e Cayman
Dis t r ibu t ion of l i t t o r a l Mollusca
C l a s s i f i c a t i o n of l i t t o r a l f i s h e s
Mean s i z e , sample s i z e and h a b i t a t preference of t h e f i s h e s found occupying s i x l i t t o r a l rock pools
T e r r e s t r i a l fauna of L i t t l e Cayman (excluding b i r d s and i n s e c t s ) , J u l y and August 1975
Species d i v e r s i t y i n each of the h a b i t a t types
Numbers of l i v i n g a d u l t Cerion nanus and Cerion pannosum found on Evolvulus p l a n t s , and the numbers of empty
Page 2
5
32
3 6
4 5
4 6
8 4
87
s h e l l s of t he two spec ie s per 0.25 sq m , a t s i t e s A and B 94
Numbers of Evolvulus p l a n t s with and without Cerion of e i t h e r spec ie s a t s i t e s A and B 94
Numisers sf Evolvulus p l a t s car ry ing I.ive Cerion of one or both spec ies a t s i t e 8. The expected f i g u r e s assume a randoul d i s t r i b u t i o n of each spec ie s 9 0
Ordina~l d i s t r i b u t i o n of spec ies of i n s e c t s f o - a d on L i t t l e Cayman. N u h e r s of spec ies f o r North Mmerica nor th of Mexico a r e from Borror and DeLong (1966)
Within-family s i z e ranges of L i t t l e Cayman and B r i t i s h i n s e c t s . Dimensions a r e body length (excluding antennae and abdominal appendages) except f o r Odonata, Neuroptera and Lepidoptera where wing expanse i s given, and Scarabaeidae f o r which e l y t r a l length i s shown
Percentage composition of sweep-net saniples from L i t t l e Cayman compared with those repor ted by Janzen and Pond (1975) from Michigan, U.S.A.
xiv
Percentage composition of Malaise t r a p samples from L i t t l e Cayman, and from Surinam and Kansas (Matthews and Matthews 1971) 110
Comparison of l i g h t t r a p ca t ches of Macrolepidoptera on L i t t l e Cayman and a t Woodchester Park, Glouces te rsh i re , England. 111
Numbers of spec i e s caught by d i f f e r e n t methods on L i t t l e Cayman. F igu re s i n paren theses show t h e numbers of spec i e s caught only by the method i n d i c a t e d , and the percentages a r e of t h e numbers of spec i e s caught by each method o u t of t h e t o t a l number of spec i e s found on the i s l a n d belonging t o t h e group
Species of Odonata recorded from t h e Cayman I s l a n d s by t h e 1938 Oxford Univers i ty Expedi t ion and t h e 1975 Royal Society and Cayman I s l a n d s Government Expedi t ion
B u t t e r f l y spec i e s recorded by the 1938 and 1975 Expedi t ions t o t h e Cayman I s l a n d s
Matrix showing the numbers of spec i e s shared bstween Cuba, Hispaniola , Puer to Rico, Jamaica and t h e Cayman I s l ands (upper r i g h t ) , va lues f o r C o l e ' s c o e f f i c i e n t of a s s o c i a t i o n (lower l e f t ) , and t h e t o t a l number of b u t t e r f l y spec i e s recorded f o r each i s l a n d 132
Numbers of b u t t e r f l i e s counted p e r f i v e minutes i n each h a b i t a t zone on t h r e e t r a n s e c t s of L i t t l e Cayman 135
The spec i e s of land-birds breeding i n t h e Cayman I s l ands , and t h e i r d i s t r i b u t i o n elsewhere 14 3
D i s t r i b u t i o n a l a f f i x i t i e s of the breeding land--birds of the Cayman 1sianc"is and L i t t l e Cayman, F igures i n b racke t s show t h e nl-1;nber of Cen t r a l A ~ ~ r i c a n s p c c i e s t h a t a r e r e s t r i c t e d t o offs i lore i s l a n d s - 144
The endemic forms of Cay~iian i s l a n d s land-b i rds , and t h e i s l a n d s on which they breed. Popula-tions probably ex t inc - t a r e bracketed 145
D i s t r i b u t i o n of Cayman I s l a n d s endemic land-b i rds . F igures i n b racke t s show t o t a l s before r e c e n t e x t i n c t i o n s
Ex t inc t ions and c o l o n i s a t i o n s i n t h e Cayman I s l a n d s a v i f auna 149
Breeding records of L i t t l e Cayman b i r d s , 9 July-11 August 19 75 150
28 . Average number of b i r d s p e r hour recorded i n four h a b i t a t s on L i t t l e Cayman
29. Habi ta t s of breeding b i r d s of L i t t l e Cayman 15 2
30. Feeding methods of four insec t ivorous passe r ines on L i t t l e Cayman 154
31. Census of boobies along t h e southern edge of t h e colony, 0800-1000, 1 August 1975 167