Communities Structure of Reef Corals
259
Most alcyonaceans and many gorgonian octocorals have in their polyps
the algal symbionts zooxanthellae, the same as scleractinian corals (Kinzie
1974). Among common symbiotic alcyonaceans there could be mentioned
the genera Alcuonium, Lithophyton, Lobophytom, Sarcophyton, Sinularia,
Capnella, Cladiella, Lemnalia, Pralemnalia, the stolonifera coral Tubipora,
the coral Heliopora (fam. Helioporaceae), and genera of the family
Xeniidae. Among the gorgonacean soft corals are: Isis, Rumphella, Eunicea,
Pseudopterogorgia, Plexaura, and Plexaurella. Asymbiotic alcyonaceans and
gorgonians often could also be found in well-illuminated zones of the reef,
though most often they prefer deeper dark biotopes, caves or channels.
These are the alcyonaceans Nephthea, Dendronephthea, Clavularia,
Pashyclavularia, and the gorgonians Bebryce, Acabaria, Mopsella, and
luncella.
7.2 Communities Structure of Reef Corals
7.2.1 General Considerations
Since World War II, studies on the structure of coral communities and their
zonal distribution received an impulse after the introduction of scuba diving
and the development of underwater photography. During these studies, the
transsect method was most often used, i.e., the recording of species of corals
along the rope or the chain laid across the reef by scuba divers. This method
is more effective if the recording of coral colonies proceeds within squares
placed on the bottom along the transsect (Loya and Siobodkin 1971; Loya
1972; Stoddart and Johannes 1978; Kenchington 1984). To study coral
communities in deeper zones of the reef, submersibles have been employed
(Lang 1974; Fricke and Schuhmachez 1983; Reed 1985). The dynamics of
coral communities in time has been observed with the aid of photogranmetric monitoring (Done 1981; Bright et al. 1984). Parameters of species
diversity and distribution of coral communities are calculated using most
often Shannon-Winer's Index H' (Loya 1972; Pichon and Morrisey 1981),
cluster analysis (Done 1982) and the methodology of modeling (Abel et al.
1983).
The space distribution of the corals' taxa in bottom reef biotopes could be
taken as the static reflection of the structure of their communities, because it
is the result of both the stochastic processes of recruitment, growth and
survival of individual corals, and of the regular socio-ecological rel~tionships
between their specific populations, and between them and the environment
as well (Dana 1976). Among the factors controlling the space distribution of
corals the following could be mentioned: (1) the vector gradients of
parameters of physical stress, like waves, currents, tide height, nutrients
concentration, illumination, turbidity of water; (2) social factors: formation
259
Most alcyonaceans and many gorgonian octocorals have in their polyps
the algal symbionts zooxanthellae, the same as scleractinian corals (Kinzie
1974). Among common symbiotic alcyonaceans there could be mentioned
the genera Alcuonium, Lithophyton, Lobophytom, Sarcophyton, Sinularia,
Capnella, Cladiella, Lemnalia, Pralemnalia, the stolonifera coral Tubipora,
the coral Heliopora (fam. Helioporaceae), and genera of the family
Xeniidae. Among the gorgonacean soft corals are: Isis, Rumphella, Eunicea,
Pseudopterogorgia, Plexaura, and Plexaurella. Asymbiotic alcyonaceans and
gorgonians often could also be found in well-illuminated zones of the reef,
though most often they prefer deeper dark biotopes, caves or channels.
These are the alcyonaceans Nephthea, Dendronephthea, Clavularia,
Pashyclavularia, and the gorgonians Bebryce, Acabaria, Mopsella, and
luncella.
7.2 Communities Structure of Reef Corals
7.2.1 General Considerations
Since World War II, studies on the structure of coral communities and their
zonal distribution received an impulse after the introduction of scuba diving
and the development of underwater photography. During these studies, the
transsect method was most often used, i.e., the recording of species of corals
along the rope or the chain laid across the reef by scuba divers. This method
is more effective if the recording of coral colonies proceeds within squares
placed on the bottom along the transsect (Loya and Siobodkin 1971; Loya
1972; Stoddart and Johannes 1978; Kenchington 1984). To study coral
communities in deeper zones of the reef, submersibles have been employed
(Lang 1974; Fricke and Schuhmachez 1983; Reed 1985). The dynamics of
coral communities in time has been observed with the aid of photogranmetric monitoring (Done 1981; Bright et al. 1984). Parameters of species
diversity and distribution of coral communities are calculated using most
often Shannon-Winer's Index H' (Loya 1972; Pichon and Morrisey 1981),
cluster analysis (Done 1982) and the methodology of modeling (Abel et al.
1983).
The space distribution of the corals' taxa in bottom reef biotopes could be
taken as the static reflection of the structure of their communities, because it
is the result of both the stochastic processes of recruitment, growth and
survival of individual corals, and of the regular socio-ecological rel~tionships
between their specific populations, and between them and the environment
as well (Dana 1976). Among the factors controlling the space distribution of
corals the following could be mentioned: (1) the vector gradients of
parameters of physical stress, like waves, currents, tide height, nutrients
concentration, illumination, turbidity of water; (2) social factors: formation