5 – Coral Reef Habitats and Assemblages
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habitats and habitat associations. Although some
authors have lumped the entire range of environmental factors such as temperature, water quality and so
forth into the definition of an organism’s ‘habitat’, we
instead will use a more literal definition of habitat from
the latin habitare ‘the place where something lives’ (see
Box 5.1). So ‘habitat’ under this definition becomes a
spatial concept, and reflects an emphasis on habitat as
BOX 5.1 GLOSSARY
Assemblage. A set of the organisms that occur at any defined level of habitat. Occasionally
used interchangeably with ‘community’, the complete set of ecologically interacting
species.
Facultative habitat associate. A species usually found in a particular habitat patch type,
but which can survive in other habitats, such as the damselfish Pomacentrus moluccensis.
Habitat. In a strict sense, the place where an organism lives. Usually considered at one of
several spatial scales.
Habitat determiner. An organism that interacts with, and alters the impact of, a habitat
former. Crown-of-thorns starfish are habitat determiners. Their predation on corals may
exert strong effects on those species reliant on the habitat structure or heterogeneity
provided by the corals.
Habitat former. An organism that generates a physical structure that forms a habitat for
another organism. Tabulate corals such as Acropora hyacinthus are habitat-formers.
Habitat generalist. A species that occurs across a wide range of habitat patch types.
Habitat homogeneity. The degree to which constituent areas forming a habitat mosaic,
habitat zone, or landscape are similar in type or distribution.
Habitat interface. The junction between different adjacent habitat patches.
Habitat mosaic. A spatially cohesive collection of habitat patches.
Habitat patch. A discrete, internally homogenous uniform area with a characteristic
physical structure or biotic composition.
Habitat responder. An organism that simply occupies habitat, without forming habitat
for others or altering the action of a habitat former.
Habitat zone. A habitat mosaic with a recognisable physiographic and environmental
setting.
Landscape/seascape. A spatially cohesive collection of mosaics or habitat zones.
Landscapes (or seascapes) are not easily defined and are perceived at a wide range of
spatial and temporal scales by marine organisms. While many coral reef organisms are
sedentary and restricted in their ability to move between habitat patches, during their
larval phase they may sample the environment at much larger spatial scales.
Microhabitat. A characteristic position within a habitat patch.
Obligative habitat associate. A species that is only found in a particular habitat patch
type, such as gobies of the genus Gobiodon.
41
habitats and habitat associations. Although some
authors have lumped the entire range of environmental factors such as temperature, water quality and so
forth into the definition of an organism’s ‘habitat’, we
instead will use a more literal definition of habitat from
the latin habitare ‘the place where something lives’ (see
Box 5.1). So ‘habitat’ under this definition becomes a
spatial concept, and reflects an emphasis on habitat as
BOX 5.1 GLOSSARY
Assemblage. A set of the organisms that occur at any defined level of habitat. Occasionally
used interchangeably with ‘community’, the complete set of ecologically interacting
species.
Facultative habitat associate. A species usually found in a particular habitat patch type,
but which can survive in other habitats, such as the damselfish Pomacentrus moluccensis.
Habitat. In a strict sense, the place where an organism lives. Usually considered at one of
several spatial scales.
Habitat determiner. An organism that interacts with, and alters the impact of, a habitat
former. Crown-of-thorns starfish are habitat determiners. Their predation on corals may
exert strong effects on those species reliant on the habitat structure or heterogeneity
provided by the corals.
Habitat former. An organism that generates a physical structure that forms a habitat for
another organism. Tabulate corals such as Acropora hyacinthus are habitat-formers.
Habitat generalist. A species that occurs across a wide range of habitat patch types.
Habitat homogeneity. The degree to which constituent areas forming a habitat mosaic,
habitat zone, or landscape are similar in type or distribution.
Habitat interface. The junction between different adjacent habitat patches.
Habitat mosaic. A spatially cohesive collection of habitat patches.
Habitat patch. A discrete, internally homogenous uniform area with a characteristic
physical structure or biotic composition.
Habitat responder. An organism that simply occupies habitat, without forming habitat
for others or altering the action of a habitat former.
Habitat zone. A habitat mosaic with a recognisable physiographic and environmental
setting.
Landscape/seascape. A spatially cohesive collection of mosaics or habitat zones.
Landscapes (or seascapes) are not easily defined and are perceived at a wide range of
spatial and temporal scales by marine organisms. While many coral reef organisms are
sedentary and restricted in their ability to move between habitat patches, during their
larval phase they may sample the environment at much larger spatial scales.
Microhabitat. A characteristic position within a habitat patch.
Obligative habitat associate. A species that is only found in a particular habitat patch
type, such as gobies of the genus Gobiodon.