412
Destruction and Recovery of Reef Systems, Reef and Man
Warious kinds of construction works significantly damaged reefs, among
them the building of airstrips and dikes, the preparation of beaches,
dredging and blasting in the construction of channels, passages and piers for
boats. In places of construction corals are killed not only directly but also by
siltation (Guilcher 1985). The same results from the extermination of forests
and the extensive agriculture in coastal areas close to reefs (Johannes 1977b;
Kuhlmann 1985, 1988b). Most reef fish in such areas also die. Many of them
being strictly terrestrial do not abandon their home ground even after being
subjected to stress (Amesbury 1981). The building sites for construction
works on many reefs were huge. For example, during construction of
airstrips on Guam and Tahiti hundreds of hectares of beautiful reefs
perished (Johannes 1970). Military construction altered the water exchange
in the lagoon of the Palmira atoll so that the corals in it died. Hundreds of
hectares of beautiful reefs perished also during the construction of a military
chemical plant at the Johnston stoll. In many countries the reefs are
endangered by excavation of sand and lime for construction works (Galzin
1981). It causes resuspension of sediments, increase in bacteria numbers by
one order of magnitude, and decrease in oxygen content. The reef
biocoenoses in areas of excavation were damaged, corals, especially the
ramose species, died (Salvat et al. 1979; Najim 1981). Corals are also
excavated as material for construction and for the production of lime
(Brown and Wells 1989). Their massive colonies are sawed up for use in
making lime plates for facings of buildings.
The level of anthropogenic stress and the state of the modern ecological
situation in different reef regions we have tried to estimate relying on
literature data (Brown 1986; Gomez 1981, 1982, Gomez et al. 1981) and our
own experience (Table 11.4) The severest stress suffer reefs of S. E. Asia.
The local people of this region have been using reef resources very
extensively for a long time. They get lime from reefs, blast and excavate reef
flat rocks, take the corals for construction, and collect shells and fish (Brown
1986). On the reefs of Hainan, where corals are taken for the souvenir trade
and aquaria, in 1960 110 species of corals were recorded, but today only 20
are left. Destructive fishery is wide spread in this region and many important
species of reef fauna are overfished. Many reefs here were inhibited and
attacked by Acanthaster. But the reefs of S. E. Asia suffer most of all from
siltation by terrigenous material coming from the fields (Soerigato 1981).
The reefs of Thailand are stressed by waste waters from the tin mines, and
by booming tourism and construction (Yap and Gomez 1983, 1984; Sudara
1988). The reefs of Polynesia and Micronesia suffer from the expansion of
tourist business, desiructive fishery, and overfishing. More than half of the
Tonga reefs are degrading. Mass mortality of corals on them proceeds,
many species of fish and molluscs have disappeared (Chesher 1985). Reefs
of New Caledonia are polluted from the nickel mines. On Hawaii arose the
problem of wastewater discharge by crowds of tourists numbering millions.
On Oahu Island these waters had been dumpted into Kaneohe bay, where
Destruction and Recovery of Reef Systems, Reef and Man
Warious kinds of construction works significantly damaged reefs, among
them the building of airstrips and dikes, the preparation of beaches,
dredging and blasting in the construction of channels, passages and piers for
boats. In places of construction corals are killed not only directly but also by
siltation (Guilcher 1985). The same results from the extermination of forests
and the extensive agriculture in coastal areas close to reefs (Johannes 1977b;
Kuhlmann 1985, 1988b). Most reef fish in such areas also die. Many of them
being strictly terrestrial do not abandon their home ground even after being
subjected to stress (Amesbury 1981). The building sites for construction
works on many reefs were huge. For example, during construction of
airstrips on Guam and Tahiti hundreds of hectares of beautiful reefs
perished (Johannes 1970). Military construction altered the water exchange
in the lagoon of the Palmira atoll so that the corals in it died. Hundreds of
hectares of beautiful reefs perished also during the construction of a military
chemical plant at the Johnston stoll. In many countries the reefs are
endangered by excavation of sand and lime for construction works (Galzin
1981). It causes resuspension of sediments, increase in bacteria numbers by
one order of magnitude, and decrease in oxygen content. The reef
biocoenoses in areas of excavation were damaged, corals, especially the
ramose species, died (Salvat et al. 1979; Najim 1981). Corals are also
excavated as material for construction and for the production of lime
(Brown and Wells 1989). Their massive colonies are sawed up for use in
making lime plates for facings of buildings.
The level of anthropogenic stress and the state of the modern ecological
situation in different reef regions we have tried to estimate relying on
literature data (Brown 1986; Gomez 1981, 1982, Gomez et al. 1981) and our
own experience (Table 11.4) The severest stress suffer reefs of S. E. Asia.
The local people of this region have been using reef resources very
extensively for a long time. They get lime from reefs, blast and excavate reef
flat rocks, take the corals for construction, and collect shells and fish (Brown
1986). On the reefs of Hainan, where corals are taken for the souvenir trade
and aquaria, in 1960 110 species of corals were recorded, but today only 20
are left. Destructive fishery is wide spread in this region and many important
species of reef fauna are overfished. Many reefs here were inhibited and
attacked by Acanthaster. But the reefs of S. E. Asia suffer most of all from
siltation by terrigenous material coming from the fields (Soerigato 1981).
The reefs of Thailand are stressed by waste waters from the tin mines, and
by booming tourism and construction (Yap and Gomez 1983, 1984; Sudara
1988). The reefs of Polynesia and Micronesia suffer from the expansion of
tourist business, desiructive fishery, and overfishing. More than half of the
Tonga reefs are degrading. Mass mortality of corals on them proceeds,
many species of fish and molluscs have disappeared (Chesher 1985). Reefs
of New Caledonia are polluted from the nickel mines. On Hawaii arose the
problem of wastewater discharge by crowds of tourists numbering millions.
On Oahu Island these waters had been dumpted into Kaneohe bay, where