Comparative Effects of Different Disturbances in Coral Reef Habitats in Moorea, French Polynesia

Abstract

Degradation and loss of critical coastal habitats has significant ramifications for marine fisheries, such that knowledge of changes in habitat quality and quantity are fundamental to effective ecosystem management. This study explores changes in the structure of coral reef habitats, specifically changes in coral cover and composition, in Moorea, French Polynesia, to assess the independent and combined effects of different disturbances since 1979. During this period, reefs on the north coast have been subject to coral bleaching, severe tropical storms, as well as outbreaks of Acanthaster. Coral cover varied significantly among years, showing marked declines during some, but not all, disturbances. The greatest rates of coral loss coincided with outbreaks of A. planci. Moreover, successive disturbances have had differential effects among coral genera, leading to strong directional shifts in coral composition. Acropora is declining in abundance and coral assemblages are becoming increasingly dominated by Pocillopora and Porites. Observed changes in the cover and composition of corals are likely to have further significant impacts on the reef fish assemblages. Given that significant disturbances have been mostly associated with outbreaks of A. planci, rather than climate change, effective ecosystem management may reduce and/or delay impending effects of climate change.

Diel pCO2 oscillations modulate the response of the coral Acropora hyacinthus to ocean acidification

“…This outcome was likely due to the small diel variation in pCO 2 that we detected (69 versus 85 µatm at upstream and downstream habitats), which is much lower than the very large daily variation in pCO 2 recently recorded in reef waters at Lady Elliot Island, Australia (Shaw et al 2012). While it is currently unknown why upstream−downstream variation in pCO 2 in reef waters in Moorea was so small at the time of measurement, it is possible that contempo-rary values reflect the low coral cover in the back reef of Moorea (Edmunds et al 2010, Trapon et al 2011), the strong cross reef transport of seawater in Moorea that lessens residence time of water over the reef (e.g. Rosman & Hench 2011), and the greater depth of water (~2 m) compared to Lady Elliot Island (~0.4 m) where diel pCO 2 variation is strongly developed (Shaw et al 2012).…”

30 Years of Research on Crown-of-thorns Starfish (1986-2016): Scientific Advances and Emerging Opportunities

“…More broadly, outbreaks of Acanthaster spp. are a major contributor to sustained declines in coral cover and degradation of coral reefs at many locations throughout the Indo west-Pacific (Osborne et al 2011;Trapon et al 2011;De'ath et al 2012).…”

“…More broadly, outbreaks of Acanthaster spp. are a major contributor to sustained declines in coral cover and degradation of coral reefs at many locations throughout the Indo west-Pacific (Osborne et al 2011;Trapon et al 2011;De'ath et al 2012).While there has been considerable research, and a larger number of scientific articles (>940) focused on Acanthaster spp., extending back to the 1960s (Goreau 1964;Pearson and Endean 1969), research interest (and funding) has waxed and waned through this period (Fig. 1).…”

“…The same is probably true for other reef regions, where outbreaks of Acanthaster spp. are among the major causes of acute coral loss (Pratchett et al 2009;Trapon et al 2011;Baird et al 2013;Pisapia et al 2016).The purpose of this review is not to provide a comprehensive overview of CoTS biology or research, which are already available elsewhere Birkeland and Lucas 1990;Pratchett et al 2014a), but to consider major advances (and apparent failings) in CoTS research over the past few decades. Our assessment of research progress is based on a critical judgment of the extent to which research (including original research presented within this special issue) has addressed the knowledge gaps highlighted by a seminal review in 1986 (Moran 1986).…”

“…Completely denuded reefs also recover much more slowly than reefs in which at least some corals survive to grow and reproduce (Connell et al 1997;Gilmour et al 2013). Moreover, it is increasingly apparent that major disturbances are occurring too frequently to allow for recovery of coral assemblages in the intervening period (Trapon et al 2011).The recovery of coral assemblages following outbreaks of A. cf. solaris was explicitly studied on the GBR based on temporal dissimiliarity in taxonomic composition of benthic assemblages on reefs (Mellin et al 2016b).…”