The World of Coral Reefs
Table 1.2: Regional patte
the clear pattern of max
rns of species
mum diversity
diversity in
in the Indo
coral reefs
Pacific reg
and related ecosystems:
on is shovim in all species groups
Taxonomic group
ndo-West Pacific
Eastern Pacific
Western Atlantic
Eastern Atlantic
Scleractinian corals'
719
34
62
Alcyonarian corals
690+
6
Sponges (general
2U
117
Gastropods;
Cypraeidae
178
24
6
9
Conus
316
30
57
22
Bivalves
2 000
564
378
427
Crustaceans:
Stomatopods
249
50
77
30
Caridean shrimps
91
28
41*
Echinoderms
1 200
208
148
Fish
iOOO
650
1400
450
Butterflytish and angelfish^
175
8
15
7
Seagrasses'
3A
7
9
2
Mangroves'
59
13
11
7
• All Atlantic
Source; Paulay 119971 except:
l.Veron 120001.
2. Allen el al 119991
3. WCMC database - figures include species with warm temperate distribu
^. Spalding et all 19971.
ions.
currents. Unfavorable currents may prevent the colonization of areas by new species, notably in the remote reef
regions of Brazil and the Eastern Pacific. The mechanisms,
and the importance of this transport, are further considered on page 23.
Changing patterns over geological time scales
Separate faunas - Atlantic and Indo-Pacific. Many of
the global patterns in reef and coral development can be
explained by looking at the tectonic and climatic history
of reefs. Scleractinian corals evolved during the Triassic
(205-250 million years ago) and quickly developed a
circum-global distribution, only restricted by areas of
suitably shallow substrate. As the continents broke up and
shifted, the global connection of tropical oceans became
more restricted. With the closure of the Tethys Sea, the
waters of the Indian Ocean and Western Pacific were
separated from those of the Atlantic and far Eastern
Pacific, and the coral reef communities in each began to
develop distinctive characteristics.
Low diversity in the Atlantic. The closure of the
isthmus of Panama divided the "western" fauna into
two. This entire region was then subjected to massive
extinctions during the Pliocene/Pleistocene glaciations,
removing many of the species which were once commonly
found on all coral reefs. The Atlantic corals now share
only seven genera with the Indo-Pacific. Even as
environmental conditions improved, continued eustatic
disruption may have prevented subsequent re-expansion
and diversification of the coral reef fauna, and there has
been little time since the end of these glaciations for any
further species radiation. The result today is clearly shown
in the far lower species diversity in the Atlantic reefs. For
scleractinian corals the Atlantic only holds about one tenth
the number of species as the Indo-Pacific, while similar
patterns hold for almost all other species groups, with
between one third and one tenth of the diversity on
Atlantic reefs as compared to Indo-Pacific reefs.
High diversity in the Indo-Pacific. The same period
of extinctions was not so extreme in the "eastern fauna",
the area now known as the Indo-Pacific. Right across
the region there are large areas of shallow coastal shelf
spanning considerable latitudinal ranges. Over these areas
there were more locations or refuges offering opportunities for survival of species during periods of environmental adversity. Species diversity remains high across
much of this region, although there is a clearer decline in
diversity moving east across the Central Pacific.
The Southeast Asian center of diversity. Quite apart
from the generally high diversity recorded across the IndoPacific, there is an area of outstanding diversity centered on
a triangle encompassing the Philippines and central and
Table 1.2: Regional patte
the clear pattern of max
rns of species
mum diversity
diversity in
in the Indo
coral reefs
Pacific reg
and related ecosystems:
on is shovim in all species groups
Taxonomic group
ndo-West Pacific
Eastern Pacific
Western Atlantic
Eastern Atlantic
Scleractinian corals'
719
34
62
Alcyonarian corals
690+
6
Sponges (general
2U
117
Gastropods;
Cypraeidae
178
24
6
9
Conus
316
30
57
22
Bivalves
2 000
564
378
427
Crustaceans:
Stomatopods
249
50
77
30
Caridean shrimps
91
28
41*
Echinoderms
1 200
208
148
Fish
iOOO
650
1400
450
Butterflytish and angelfish^
175
8
15
7
Seagrasses'
3A
7
9
2
Mangroves'
59
13
11
7
• All Atlantic
Source; Paulay 119971 except:
l.Veron 120001.
2. Allen el al 119991
3. WCMC database - figures include species with warm temperate distribu
^. Spalding et all 19971.
ions.
currents. Unfavorable currents may prevent the colonization of areas by new species, notably in the remote reef
regions of Brazil and the Eastern Pacific. The mechanisms,
and the importance of this transport, are further considered on page 23.
Changing patterns over geological time scales
Separate faunas - Atlantic and Indo-Pacific. Many of
the global patterns in reef and coral development can be
explained by looking at the tectonic and climatic history
of reefs. Scleractinian corals evolved during the Triassic
(205-250 million years ago) and quickly developed a
circum-global distribution, only restricted by areas of
suitably shallow substrate. As the continents broke up and
shifted, the global connection of tropical oceans became
more restricted. With the closure of the Tethys Sea, the
waters of the Indian Ocean and Western Pacific were
separated from those of the Atlantic and far Eastern
Pacific, and the coral reef communities in each began to
develop distinctive characteristics.
Low diversity in the Atlantic. The closure of the
isthmus of Panama divided the "western" fauna into
two. This entire region was then subjected to massive
extinctions during the Pliocene/Pleistocene glaciations,
removing many of the species which were once commonly
found on all coral reefs. The Atlantic corals now share
only seven genera with the Indo-Pacific. Even as
environmental conditions improved, continued eustatic
disruption may have prevented subsequent re-expansion
and diversification of the coral reef fauna, and there has
been little time since the end of these glaciations for any
further species radiation. The result today is clearly shown
in the far lower species diversity in the Atlantic reefs. For
scleractinian corals the Atlantic only holds about one tenth
the number of species as the Indo-Pacific, while similar
patterns hold for almost all other species groups, with
between one third and one tenth of the diversity on
Atlantic reefs as compared to Indo-Pacific reefs.
High diversity in the Indo-Pacific. The same period
of extinctions was not so extreme in the "eastern fauna",
the area now known as the Indo-Pacific. Right across
the region there are large areas of shallow coastal shelf
spanning considerable latitudinal ranges. Over these areas
there were more locations or refuges offering opportunities for survival of species during periods of environmental adversity. Species diversity remains high across
much of this region, although there is a clearer decline in
diversity moving east across the Central Pacific.
The Southeast Asian center of diversity. Quite apart
from the generally high diversity recorded across the IndoPacific, there is an area of outstanding diversity centered on
a triangle encompassing the Philippines and central and