402
Destruction and Recovery of Reef Systems, Reef and Man
communities cannot completely recover for several tens of years, Often they
do not recover at all, remaining overgrown by coralline algae and seaweeds
(Woodley et al. 1981; Pearson 1981). For example, there could be
mentioned the hurricane Hatty, which destroyed the reefs of British
Honduras in 1961. Even after 11 years they showed no signs of recovery
(Stoddard 1974). In 1980 the strongest hurricane in the century, Allen,
destroyed the reefs off Jamaica (Woodley et al. 1981). The corals were
smashed even in protected places. According to D. Stoddart, the now bare
algal flats of many Indo-oceanic reefs, were not so long ago covered with
corals, which were then extinguished by fierce typhoons and could no longer
recover.
The recovery of coral communities, damaged by cyclones of average
strength, starts with the recruitment of pieces of Acropora branches, most of
which usually survive. For example, on the Belize reefs, damaged by the
cyclone Greta with winds of 120-150 km h -1, the ramose corals were
destroyed down to a depth of 25 m. But about 40% of torn-away colonies of
Acropora palmata survived and started to implant themselves and grow at
new places. Most pieces of the branches of A. palmata and A. cervicornis
also survived and recruiting in new places began to take place, thus giving
start to the formation of new colonies (Highsmith et al. 1980). Because of
the intensive growth of these newly settled pieces of ramose corals, the rate
of calcification in these damaged reefs did not decrease but increased
(Connell 1978). Periodic cyclones are an important factor in the formation
of the zonal structure of reef bottom communities (Dollar 1982). Over 62
years, beginning with 1900, a total of 286 hurricanes passed over the
Caribbean reefs. Periodic cyclones are an important factor in the evolution
of reef corals. In perticular, this factor furthered in acroporids the ability of
pieces of their colonies to survive, quickly settle and grow fast in new places
(Highsmith et al. 1980).
In the recovery of coral communities after such catastrophic destruction
an important role is played also by the recruitment of planulae and the
growth of new coral colonies (Endean 1976). In 1975 we observed a mass
colonization of the bare reef flat at the Funafuti atoll, from which the corals
had been wiped off by the typhoon Baby in 1970, by young colonies of
Acropora hyacinthus. The colonies had an even size of 5-7 cm and had
grown up from the settled planulae. Their number attained ten per m- 2 .
The success of recolonization of damaged reef by corals depends greatly
upon the amount of sites where their colonies survived, becoming sources of
new planulae, and also upon the possibility of transfer from neighbouring,
less destroyed reefs. The success of recruitment of new planulae depends
upon the safety of the herbivorous fish populations after the cyclone, which
clean the hard substrate for their settling. Within 10 years after the cyclone
attack the colonies of Acropora attained a size of 50-70 cm. The colonies of
massive corals could attain sizes of 20-40 cm only after 20 years. The total
recovery of a coral community after the passage of a tropical cyclone takes 5
Destruction and Recovery of Reef Systems, Reef and Man
communities cannot completely recover for several tens of years, Often they
do not recover at all, remaining overgrown by coralline algae and seaweeds
(Woodley et al. 1981; Pearson 1981). For example, there could be
mentioned the hurricane Hatty, which destroyed the reefs of British
Honduras in 1961. Even after 11 years they showed no signs of recovery
(Stoddard 1974). In 1980 the strongest hurricane in the century, Allen,
destroyed the reefs off Jamaica (Woodley et al. 1981). The corals were
smashed even in protected places. According to D. Stoddart, the now bare
algal flats of many Indo-oceanic reefs, were not so long ago covered with
corals, which were then extinguished by fierce typhoons and could no longer
recover.
The recovery of coral communities, damaged by cyclones of average
strength, starts with the recruitment of pieces of Acropora branches, most of
which usually survive. For example, on the Belize reefs, damaged by the
cyclone Greta with winds of 120-150 km h -1, the ramose corals were
destroyed down to a depth of 25 m. But about 40% of torn-away colonies of
Acropora palmata survived and started to implant themselves and grow at
new places. Most pieces of the branches of A. palmata and A. cervicornis
also survived and recruiting in new places began to take place, thus giving
start to the formation of new colonies (Highsmith et al. 1980). Because of
the intensive growth of these newly settled pieces of ramose corals, the rate
of calcification in these damaged reefs did not decrease but increased
(Connell 1978). Periodic cyclones are an important factor in the formation
of the zonal structure of reef bottom communities (Dollar 1982). Over 62
years, beginning with 1900, a total of 286 hurricanes passed over the
Caribbean reefs. Periodic cyclones are an important factor in the evolution
of reef corals. In perticular, this factor furthered in acroporids the ability of
pieces of their colonies to survive, quickly settle and grow fast in new places
(Highsmith et al. 1980).
In the recovery of coral communities after such catastrophic destruction
an important role is played also by the recruitment of planulae and the
growth of new coral colonies (Endean 1976). In 1975 we observed a mass
colonization of the bare reef flat at the Funafuti atoll, from which the corals
had been wiped off by the typhoon Baby in 1970, by young colonies of
Acropora hyacinthus. The colonies had an even size of 5-7 cm and had
grown up from the settled planulae. Their number attained ten per m- 2 .
The success of recolonization of damaged reef by corals depends greatly
upon the amount of sites where their colonies survived, becoming sources of
new planulae, and also upon the possibility of transfer from neighbouring,
less destroyed reefs. The success of recruitment of new planulae depends
upon the safety of the herbivorous fish populations after the cyclone, which
clean the hard substrate for their settling. Within 10 years after the cyclone
attack the colonies of Acropora attained a size of 50-70 cm. The colonies of
massive corals could attain sizes of 20-40 cm only after 20 years. The total
recovery of a coral community after the passage of a tropical cyclone takes 5