Recovery of coral assemblages despite acute and recurrent disturbances on a South Central Pacific reef

Abstract

Coral reefs are increasingly threatened by various types of disturbances, and their recovery is challenged by accelerating, human-induced environmental changes. Recurrent disturbances reduce the pool of mature adult colonies of reef-building corals and undermine post-disturbance recovery from newly settled recruits. Using a long-term interannual data set, we show that coral assemblages on the reef slope of Moorea, French Polynesia, have maintained a high capacity to recover despite a unique frequency of large-scale disturbances which, since the 1990s, have caused catastrophic declines in coral cover and abundance. In 2014, only four years after one of the most extreme cases of coral decline documented, abundance of juvenile and adult colonies had regained or exceeded pre-disturbance levels, and no phase-shift to macroalgal dominance was recorded. This rapid recovery has been achieved despite constantly low coral recruitment rates, suggesting a high post-disturbance survivorship of recruits. However, taxonomic differences in coral susceptibility to disturbances and contrasting recovery trajectories have resulted in changes in the relative composition of species. In the present context of global coral reef decline, our study establishes a new benchmark for the capacity of certain benthic reef communities to sustain and recover their coral cover from repeated, intense disturbances.

Synchrony patterns reveal different degrees of trophic guild vulnerability after disturbances in a coral reef fish community

“…Here, we also found a strong shift in the fish community composition after the 2006 COTS outbreak and the 2010 cyclone similarly to the study by Lamy et al () and showed that these taxonomic changes are maintained during the subsequent recovery phase. Therefore, even if coral communities have partially returned to pre‐disturbance composition (Adjeroud et al, ), there is no recovery of the taxonomical composition of the fish community. The contrasting results between coral and fish communities could be interpreted as lags in the fish community response to changes in the coral community (Graham et al, ).…”

“…Moorea's coral reefs historically exhibited high recovery of coral cover and fish abundance when exposed to various environmental disturbances (Galzin et al, ; Lamy, Galzin, Kulbicki, Lison de Loma, & Claudet, ; Martin, Moritz, Siu, & Galzin, ). Although the coral community has partially returned to its pre‐disturbance composition (Adjeroud et al, ), disturbances induced long‐term composition changes in the fish community (Berumen & Pratchett, ; Lamy et al, ). Such changes first indicate that fish species respond differently to disturbances but also that the alteration of the fish community persists for at least a few years after coral cover recovery.…”

Predicting coral community recovery using multi‐species population dynamics models

“…; Adjeroud et al . ). In turn, a decline in coral abundance, composition, and size can reduce the provision of ecosystem services, largely because mixed assemblages of corals create complex physical structures that form habitat for a diversity of organisms (Graham et al .…”

“…; Adjeroud et al . ). Recovery has been observed in cases where surviving coral colonies regrow, larval supply from remote populations facilitate recolonization, and/or grazing fishes control macroalgal growth (Gilmour et al .…”

“…This is especially true for tropical coral reefs that provide a plethora of ecosystem services yet are being degraded at an increasing rate by human activities (Hughes et al 2017). Coral reefs are impacted by storms, predator outbreaks, bleaching events, and other environmental perturbations that reduce live coral cover, the abundance and size of coral colonies, and coral taxonomic diversity (De'ath et al 2012;Riegl et al 2017;Adjeroud et al 2018). In turn, a decline in coral abundance, composition, and size can reduce the provision of ecosystem services, largely because mixed assemblages of corals create complex physical structures that form habitat for a diversity of organisms (Graham et al 2008;Fabricius et al 2014;Holbrook et al 2015;Lamy et al 2016;Darling et al 2017), provide refuge from multiple kinds of stress (Schmitt & Holbrook 2007;Lenihan et al 2008;Kayal et al 2011;Bozec et al 2013), as well as support fisheries that benefit millions of people (Cinner et al 2012;Rogers et al 2014).…”