Cernohorsky N.H.,Masaryk University |
McClanahan T.R.,Wildlife Conservation Society |
Babu I.,Coral Reef Research |
Horsak M.,Masaryk University
Coral Reefs | Year: 2015
Despite large herbivorous fish being generally accepted as the main group responsible for preventing algal accumulation on coral reefs, few studies have experimentally examined the relative importance of herbivore size on algal communities. This study used exclusion cages with two different mesh sizes (1 × 1 cm and 6 × 6 cm) to investigate the impact of different-sized herbivores on algal accumulation rates on the shallow (<2 m) back-reef of Agatti atoll, Lakshadweep. The fine-mesh cages excluded all visible herbivores, which had rapid and lasting effects on the benthic communities, and, after 127 d of deployment, there was a visible and significant increase in algae (mainly macroalgae) with algal volume being 13 times greater than in adjacent open areas. The coarse-mesh cages excluded larger fishes (>8 cm body depth) while allowing smaller fishes to access the plots. In contrast to the conclusions of most previous studies, the exclusion of large herbivores had no significant effect on the accumulation of benthic algae and the amount of algae present within the coarse-mesh cages was relatively consistent throughout the experimental period (around 50 % coverage and 1–2 mm height). The difference in algal accumulation between the fine-mesh and coarse-mesh cages appears to be related to the actions of small individuals from 12 herbivorous fish species (0.17 ind. m−2 and 7.7 g m−2) that were able to enter through the coarse mesh. Although restricted to a single habitat, these results suggest that when present in sufficient densities and diversity, small herbivorous fishes can prevent the accumulation of algal biomass on coral reefs. © 2015 Springer-Verlag Berlin Heidelberg
Veron J.,Coral Reef Research |
Veron J.,University of Queensland |
Veron J.,James Cook University
Zoological Journal of the Linnean Society | Year: 2013
Coral taxonomy has entered a historical phase where nomenclatorial uncertainty is rapidly increasing. The fundamental cause is mandatory adherence to historical monographs that lack essential information of all sorts, and also to type specimens, if they exist at all, that are commonly unrecognizable fragments or are uncharacteristic of the species they are believed to represent. Historical problems, including incorrect subsequent type species designations, also create uncertainty for many well-established genera. The advent of insitu studies in the 1970s revealed these issues; now molecular technology is again changing the taxonomic landscape. The competing methodologies involved must be seen in context if they are to avoid becoming an additional basis for continuing nomenclatorial instability. To prevent this happening, the International Commission on Zoological Nomenclature (ICZN) will need to focus on rules that consolidate well-established nomenclature and allow for the designation of new type specimens that are unambiguous, and which include both skeletal material and soft tissue for molecular study. Taxonomic and biogeographic findings have now become linked, with molecular methodologies providing the capacity to re-visit past taxonomic decisions, and to extend both taxonomy and biogeography into the realm of evolutionary theory. It is proposed that most species will ultimately be seen as operational taxonomic units that are human rather than natural constructs, which in consequence will always have fuzzy morphological, genetic, and distribution boundaries. The pathway ahead calls for the integration of morphological and molecular taxonomies, and for website delivery of information that crosses current discipline boundaries. © 2013 The Author. Zoological Journal of the Linnean Society published by John Wiley & Sons Ltd on behalf of The Linnean Society of London.
Vo S.T.,Vietnam Academy of Science and Technology |
DeVantier L.,Coral Reef Research |
Tuyen H.T.,Vietnam Academy of Science and Technology |
Hoang P.K.,Vietnam Academy of Science and Technology
Raffles Bulletin of Zoology | Year: 2014
Reef geomorphology, species composition and community structure of reef-building corals of Ninh Hai (south central Vietnam) were investigated from 2003-2011, contributing towards development of an integrated, representative national and regional network of Marine Protected Areas. Ninh Hai hosts extensive and diverse fringing coral reefs covering more than 2,300ha, the result of favourable physico-chemical conditions of sea temperature, water clarity, and sediment levels. These well-developed fringing reefs are rare or absent in other parts of Vietnam, and hence provide a high degree of complementarity to the developing national MPA network. The fringing reefs of Ninh Hai are in relatively good condition (average live coral cover > 25%), comprised of some 310 species from 60 genera of reef-building coral, including 11 species and one genus (Scapophyllia) previously unknown from the western South China Sea. Coral community structure shows considerable differences with other reefs in Vietnam. With the adjacent dry coastal forest ecosystem, these reefs are now protected within the Nui Chua National Park, one of very few examples of integrated conservation management of a terrestrial-coastal marine ecosystem in Vietnam or indeed Southeast Asia. The regular presence of cool water upwelling during the summer months may provide a "refuge" against future reef degradation from extensive coral death from 'bleaching' during episode of elevated sea temperatures. These reefs may thus aid in replenishment of other reefs, via dispersal and recruitment of corals locally and regionally. © National University of Singapore.
Veron J.E.N.,Coral Reef Research
Diversity | Year: 2011
This article summarises the sometimes controversial contributions made by the different sciences to predict the path of ocean acidification impacts on the diversity of coral reefs during the present century. Although the seawater carbonate system has been known for a long time, the understanding of acidification impacts on marine biota is in its infancy. Most publications about ocean acidification are less than a decade old and over half are about coral reefs. Contributions from physiological studies, particularly of coral calcification, have covered such a wide spectrum of variables that no cohesive picture of the mechanisms involved has yet emerged. To date, these studies show that coral calcification varies with carbonate ion availability which, in turn controls aragonite saturation. They also reveal synergies between acidification and the better understood role of elevated temperature. Ecological studies are unlikely to reveal much detail except for the observations of the effects of carbon dioxide springs in reefs. Although ocean acidification events are not well constrained in the geological record, recent studies show that they are clearly linked to extinction events including four of the five greatest crises in the history of coral reefs. However, as ocean acidification is now occurring faster than at any know time in the past, future predictions based on past events are in unchartered waters. Pooled evidence to date indicates that ocean acidification will be severely affecting reefs by mid century and will have reduced them to ecologically collapsed carbonate platforms by the century's end. This review concludes that most impacts will be synergistic and that the primary outcome will be a progressive reduction of species diversity correlated with habitat loss and widespread extinctions in most metazoan phyla. © 2011 by the authors.