Greater multihabitat use in Caribbean fishes when compared to their Great Barrier Reef counterparts

Journal Publication ResearchOnline@JCU
Hemingson, Christopher R.;Bellwood, David R.
David Bellwood
Abstract

Organisms often utilise different habitats for different reasons, whether it be for acquiring resources, avoiding predation or for reproduction. In coastal tropical ecosystems, coral reefs, seagrass beds and mangrove forests frequently occur in a complex mosaic of intermixed habitats. One of the most commonly identified links between these habitats is the nursery function; that some fish species utilise mangroves and seagrass as juveniles before moving onto reefs as adults. We investigated whether this potential link between habitats is reflected in the similarity of their fish assemblages and if this similarity differs between major biogeographic realms. Visual surveys in the three focal habitats in the Caribbean and on the Great Barrier Reef (GBR) provided assemblage composition data. We found a near ten-fold increase in the percentage of species that occupy all three habitats in the Caribbean when compared to the GBR. When only assessing species that occurred in multiple habitats, the Caribbean displayed strong shifts linked to ontogeny and greater abundances of multihabitat species, supporting the proposed nursery function. GBR assemblages remained more distinct regardless of ontogeny, offering little support for the nursery function. Most multihabitat species in the Caribbean reach larger adult body sizes (>= 30 cm, e.g. Haemulon flavolineatum) vs. smaller bodied (<30 cm, e.g. Halicheores miniatus) fishes on the GBR. When placed in this context, Caribbean species have a greater capacity to move and utilise more habitats compared to the limited movement from the smaller GBR species. The Caribbean and GBR therefore differ not only in the extent of species overlap between the three habitats, but also in the level of ontogenetic connectivity. It is likely that biogeographic history, evolution and tides, amongst other factors, influence these patterns.

Journal

Estuarine, Coastal and Shelf Science

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239

ISBN/ISSN

1096-0015

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Pages Count

8

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Publisher

Elsevier

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DOI

10.1016/j.ecss.2020.106748