Effect of shading by the table coral Acropora Hyacinthus on understory corals. [Acropora; Pocillopora]

Journal Article · Fri Feb 01 04:00:00 EST 1985 · Ecology; (United States)

OSTI ID:5779853

Stimson, J

Field surveys at Enewetak Atoll, Marshall Islands, show that coral density and diversity is much lower beneath Acropora table corals than in adjacent unshaded areas. Additionally, the understory community is predominantly composed of massive and encrusting species, while branching Acropora and Pocillopora predominate in unshaded areas. Results of experiments in which coral fragments were transferred to the shade of table Acropora and to adjacent unshaded areas show that shading slows the growth and leads to higher mortality of branching species, while massive and encrusting species are unaffected. Light measurements made beneath table Acropora show that illumination and irradiance values fall to levels at which most hermatypic corals do not occur. The fast-growing but fragile table Acropora are abundant in a wide variety of atoll habitats and grow rapidly to form a canopy approx. = 50 cm above the substrate. However, table Acropora also have high mortality rates, so that there is continuous production of unshaded areas. The growth and death of tables thus create local disturbances, and the resulting patchwork of recently shaded and unshaded areas may enhance coral diversity in areas of high coral cover.

• Research Organization: Univ. of Hawaii, Honolulu
• DOE Contract Number: AC08-76EV00703
• OSTI ID: 5779853
• Journal Information: Ecology; (United States), Journal Name: Ecology; (United States) Vol. 66:1; ISSN ECOLA
• Country of Publication: United States
• Language: English

Related Subjects

520100* -- Environment
Aquatic-- Basic Studies-- (-1989)
54 ENVIRONMENTAL SCIENCES
ABUNDANCE
BIOLOGICAL EFFECTS
CNIDARIA
COMPETITION
CORALS
DATA
ECOLOGY
ELECTROMAGNETIC RADIATION
ENIWETOK
EXPERIMENTAL DATA
GROWTH
HABITAT
INFORMATION
ISLANDS
MARSHALL ISLANDS
MICRONESIA
MORTALITY
NUMERICAL DATA
OCEANIA
POPULATION DENSITY
RADIATIONS
SPECIES DIVERSITY
VARIATIONS
VISIBLE RADIATION