Impact of coral predators on tropical reefs

Abstract

It is well known that herbivores have numerous and diverse impacts on plant and algal fitness, community structure and ecosystem function. The importance of corallivory as a selective force, however, has been underestimated. Corallivores, or consumers of live coral tissue, employ a wide variety of feeding strategies and can be obligate or facultative coral feeders. Our literature review reveals a complex array of corallivores across the globe, represented by 11 families of fishes and 5 invertebrate phyla and totaling over 160 species known to consume scleractinian corals worldwide. Importantly, although these corallivores span a wide taxonomic range, we found that they have been reported to feed on relatively few genera of hard corals, specifically, on only 28 scleractinian genera worldwide. Damage by corallivores ranges from minor to lethal, but there is a growing body of evidence to support that even limited removal of tissue or skeletal structures has growth and/or fitness consequences for a scleractinian coral colony. In light of increasing reef stressors and diminishing coral populations, we suggest that the role of corallivores in reef trophodynamics is more complex than appreciated previously.

Marked Ecological Shifts in Seagrass and Reef Molluscan Communities Since the Mid-Holocene in the Southwestern Caribbean

“…Anachis contributed 0.5% of total skeletal biomass in the present day, yet only 0.2% of fossil biomass. Coralliophila, a corallivorous carnivore (Rotjan and Lewis 2008), was found only in fossil samples where it constituted 0.33% of molluscan skeletal mass.…”

“…(1) The predatory gastropod Coralliophila was present in our fossil samples but entirely absent from our modern forereef-crest samples. Coralliophila predates upon hermatypic corals (Rotjan and Lewis 2008) and its absence in the present day may reflect the overwhelming decline in extent and structure of Caribbean reef corals since the mid-Holocene Precht 2001, Gardner et al 2003). (2) Some species of Anachis, an uncommon gastropod in all our samples but more prevalent in the modern day, are known to consume recently settled juvenile ascidians (Osman and Whitlatch 2004).…”

Relative gut lengths of coral reef butterflyfishes (Pisces: Chaetodontidae)

“…General categorisations include planktivores (e.g., Allen et al 1998), herbivores (e.g., Bouchon-Navaro 1986) and general omnivores (e.g., Bouchon-Navaro 1986). Unique to the butterflyfishes are the large number of species that have facultative or obligate usage of coral tissue as a prey source (see Rotjan and Lewis 2008). Coral-feeders in the genus Chaetodon have attracted a great deal of attention in the context of their role as potential indicator species (e.g., Crosby and Reese 1996), particularly those butterflyfish species that feed obligately and exclusively on corals (e.g., Chaetodon trifascialis, Irons 1989).…”

The corallivorous flatworm Amakusaplana acroporae: an invasive species threat to coral reefs?

“…Coral reefs, one of the most biodiverse and productive ecosystems in the world, are sensitive to a range of perturbations including the potentially devastating effects of corallivory, defined as the direct assimilation of live coral tissue (Hughes et al 2007;Rotjan and Lewis 2008).…”