Geography and Ecology of Diego Garcia Atoll, Chagos Archipelago.

294 Pages·2006·12.17 MB·English

ATOLL RESEARCH
BULLETIN
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'ISIE SrnSONIAN INSmZTTION
Washington, D.C, U.S.A.
ATOLL RESEARCH BULLETIN
No. 14,9
GEOGRAPHY AND ECOLOGY OF DIEGO GARCIA
ATOLL, CHAGOS ARCHIPELAGO
Edited by
D. R. Stoddart and J. D. Taylor
Issued by
THE SMITHSONIAN INSTITUTION
Washington, D.C., U.S.A.
August 27, 1971
ACKNOWLEDGEMENT
The Atoll Research Bulletin is issued by the Smithsonian
Institution as a part of its Tropical Biology Program. It is co-
sponsored by the Museum of Natural History, the Office of Environ-
mental Sciences, and the Smithsonian Press. The Press supports
and handles production and distribution. The editing is done by
the Tropical Biology staff, Botany Department, Museum of Natural
History.
The Bulletin was founded and the first 117 numbers issued by the
Pacific Science Board, National Academy of Sciences, with financial
support from the Office of Naval Research. Its pages were largely
devoted to reports resulting from the Pacific Science Board's Coral
Atoll Program.
The sole responsibility for all statements made by authors of
papers in the Atoll Research Bulletin rests with them, and statements
made in the Bulletin do not necessarily represent the views of the
Smithsonian nor those of the editors of the Bulletin.
Editors
F. R. Fosberg
M.-H. Sachet
Smithsonian Institution
Washington, D. C. 20560
D. R. Stoddart
Department of Geography
University of Cambridge
Downing Place
Cambzidge, England
"I make it my province to dwell in this prelimi-
nary discourse on those objects only, which most
excited my attention. Among the number of these
I reckon, for instance, the harbour of Diego
Garcia, and the prospect of the island itself is
pleasant. We judged to have twelve leagues in
circumference. Its form resembles a horse shoe.
Its greatest breadth is not above a quarter of a
league; the ground is however sufficiently ele-
vated to serve as a fence and shelter to a vast
reservoir of sand, which affords spacious room
to the most numerous fleets. This level is four
leagues long, and its main breadth is about one
league. Its excellent harbour has two entrances
to the north. The roads are extremely fine. Its
situation I ascertain it to be in the 7 deg. 14
min. South Latitude, and in the 68 degree east
longitude from the meridian of Paris."
A B B ~R OCHON (1793, 48-49)
"This Island is one of the wonderful phaenomena
of this globe."
JAMES HORSBURGH (1809, 131)
Contributors
W. R. P. Bourne
62 Vicarage Road, Watford, England
A. A. Bullock
Royal Botanic Gardens, Kew , Richmond, Surrey, England
(retired)
A. M. Clark
Department of Zoology, British Museum (Natural History),
London, S.W.7., England
F. R. Fosberg
Smithsonian Institution, National Museum of Natural
History, Washington, D.C. 20560, U.S.A.
J. F. Peake
Department of Zoology, British Museum (Natural History),
London, S.W.7., England
C. F. Rhyne
Department of Botany, University of North Carolina, Chapel
Hill, N.C. 27514, U.S.A. (formerly Smithsonian Institution,
Washington, D.C. 20560, U.S.A.)
B. R. Rosen
School of Physics, The University, Newcastle-on-Tyne,
England (formerly Department of Geology, University College
of Wales, Aberystwyth, Wales)
R. Sims
Department of Zoology, British Museum (Natural History),
London, S.W.7., England
W. A. Smith
Department of Zoology, British Museum (Natural History),
,
London, S .W.7. England
D. R. Stoddart
Department of Geography, University of Cambridge, England
J. D. Taylor
Department of Zoology, British Museum (Natural History)
London, S.W.7., England
C. C. Townsend
c/o Royal Botanic Gardens, Kew, Richmond, Surrey, England
Contents
Page
Scientific studies at Diego Garcia Atoll
D. R. Stoddart
Geomorphology of Diego Garcia Atoll
D. R. Stoddart
Diego Garcia climate and marine environment
D. R. Stoddart
Observations on the shallow-water marine fauna
J. D. Taylor
Marine algae of Diego Garcia
C. F. Rhyne
Annotated check list and bibliography of corals
of the Chagos Archipelago (including the recent
collection from Diego Garcia), with remarks on
their distribution
B. R. Rosen
Echinoderms from Diego Garcia
A. M. Clark and J. D. Taylor
Crustacea: Brachyura and Anomura from Diego
Garcia
J. D. Taylor
Crustacea: Cirripedes from Diego Garcia
W. A. Smith
Marine Mollusca from Diego Garcia
J. D. Taylor
Land vegetation of Diego Garcia
D. R. Stoddart
List of Diego Garcia vascular plants
F. R. Fosberg and A. A. Bullock
List of Diego Garcia Bryophyta
C. C. Townsend
Terrestrial fauna af Diego Garcia and other
Chagos atolls
D. R. Stoddart
Page
15. Earthworms of Diego Garcia 171
R. Sims
16. Non-marine Mollusca of Diego Garcia
J. F. Peake
17. The birds of the Chagos Group, Indian Ocean
W. R. P. Bourne
18. Settlement and development of Diego Garcia
D. R. Stoddart
19. Bibliography of Diego Garcia
D. R. Stoddart
TABLES
Page
. . . . . .
Scientific studies at Diego Garcia 3
Studies of marine biota by the Percy
. . . . . . . . . .
Sladen Trust Expedition 5
Characteristics of some beach, dune and
. . . . . . . .
barachois sediments at Diego Garcia 16
Characteristics of some lagoon sediments
. . . . . . . . . . . . . . . .
at Diego Garcia 25
Genera and subgenera of scleractinian corals
collected by expeditions to the Chagos
. . . . . . . . . . . . . . . . . . .
Archipelago. 69
Genera and subgenera of scleractinian corals
recorded from each atoll of the Chagos
. . . . . . . . . . . . . . . . . . . .
Archipelago 69
Crustacea recorded by the Percy Sladen
. . . .
Expedition in the Chagos Archipelago 165
Insects recorded by the Percy Sladen
. . . . . . .
Expedition in the Chagos Archipelago 166
Observations of birds at sea between 0-15'S,
182
FIGURES
1. The western Indian Ocean, showing the
. . . . . . . .
location of Diego Garcia Frontispiece
Following
page
. . . . . . . . . . . . . . . .
2. Diego Garcia Atoll 26
. . . . . . .
3. Bathymetry of the Chagos Archipelago 11
. . . . . .
4. Profiles of the land rim of Diego Garcia I I
5. Barachois Maurice. Based on Crown Copyright
. . . . . . . . . . . . . . . . . .
air photographs
$1
Following
Barachois Sylvain. Based on Crown Copyright
. . . . . . . . . . . . . . . . . .
air photographs
. . . . . . . . . . . .
Profiles in Barachois Maurice
. . . . . . . .
Profile of the land rim at Cust Point
. . . . . . . . . . . . . . . . . . . . .
West Island
. . . . . . . . . . . . . . . . . . . .
MiddleIsland
. . . . . . . . . . . . . . . . . . . . .
East Island
Profiles of the seaward reef front, north side
. . . . . . . . . . . . . . . . . . .
of the atoll
. . . . . . . . . . .
Bathymetry of the lagoon floor
. . . . . . . . . . . .
Profiles of the lagoon floor
Hypsometric curves for lagoons of atolls in the
. . . . . . . . . . . . . . . .
Chagos Archipelago
. . . . . . . . . . . .
Location of sediment samples
Cumulative frequency curves for sediment
. . . . . . . . . . . . . . . . . . . . . .
samples
Cumulative frequency curves for lagoon floor
. . . . . . . . . . . . . . . . .
sediment samples
Surface wind frequencies for each month at 0000,
. . . . . . . . . . .
0600 and 1200 GMT, 1956-1960
Surface wind frequencies for each month at 0000,
. . . . . . . .
0600, 1200 and 1800 (SIT, 1961-1965
Occurrence of calms, (a) 1956-1960, (b) 1961-
. . . . . . . . . . . . . . . . . . . . . . .
1965
. . . . . . . . . . .
Monthly temperatures 1951-1967
. . . . . . . .
Monthly rainfall 1937-1938, 1950-1966
. . . . . .
Mean rainfall per rain day for each month
Tidal records at East Point and Eclipse Point,
. . . . . . . . . . . . . . . . . .
June-July 1967 30
Intertidal zonation on the seaward shore of
. . . . . . . . . . . . . . . . . . . .
WestIsland 39
Intertidal zonation on seaward beachrock at
. . . . . . . . . . . . . . . . . . . .
SouthPoint !1
Intertidal zonation on a cobbled lagoon
. . . . . . . . . . . . . . . . . .
shore, Carcasse !f
Intertidal zonation on beach rock, entrance to
. . . . . . . . . . . . . . . . .
Barachois Maurice !1
Intertidal zonation on the reef platform at
. . . . . . . . . . . . . . . . . .
Northwest Point ,I
. . . . . . . . . . . . .
Distribution of vegetation 142
The Chagos Archipelago and neighbouring islands,
. . . . . . . . . . .
from -The English Pilot (1755) 217
The Chagos Archipelago and neighbouring islands,
showing eighteenth century exploratory
voyages, from the Neptune Oriental of D'Apr'es
. . . . . . . . . . . . . . ,,
de Mannevillette (1755)
Place names and topography of Diego Garcia on
the maps of Draper (1824), Hoart and Hoart
(c. l824), and Hoart (c. l82S), and
. . . . . . . . . . . . .
according to G. C. Bourne 11