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Article
Contrasting shifts in coral assemblages with increasing disturbances
Coral Reefs
  • Morgan S. Pratchett, James Cook University
  • Michael J. McWilliam, James Cook University
  • Bernhard Riegl, Nova Southeastern University
ORCID
0000-0002-6003-9324
ResearcherID
F-8807-2011
Document Type
Article
Publication Date
6-1-2020
Keywords
  • Climate change,
  • Community shifts,
  • Coral reefs,
  • Modelling
Abstract

Increasing incidence of major disturbances is contributing to extensive and widespread coral loss, thereby undermining the biodiversity, structure and function of reef ecosystems. The composition of coral assemblages is already changing due to selective effects of recurrent disturbances, combined with marked differences in the underlying life-history dynamics of corals, which affects their recovery. This study quantifies the effects of varying disturbance regimes on two groups of corals with divergent life histories: short-lived species with rapid growth (bushy and tabular Acropora) and long-lived species with slow growth (massive and columnar Porites). Inter-decadal shifts in the coral assemblages across four locations suggest that a high frequency of moderate disturbances favours Porites, whereas infrequent, but severe disturbances favour rapidly replenishing Acropora. Using empirical modelling, we expand these observations to show that Acropora continues to dominate so long as the interval between major disturbances is > 2 years. The only disturbance regime we considered that favoured Porites was high frequency (2-year recurrence) of moderate disturbance, whereas high frequency of severe disturbances led to local extirpation of both Acropora and Porites. Our results show that increasing incidence of major disturbances will not necessarily lead to selective loss of species that are most susceptible to disturbance, as long as these species can continue to colonise vacant space and grow quickly in the aftermath of such disturbances. This study highlights the need to consider the sensitivity of taxa to changes in both disturbance frequency and severity when forecasting changes in the composition of coral assemblages under new disturbance regimes.

DOI
10.1007/s00338-020-01936-4
Citation Information
Morgan S. Pratchett, Michael J. McWilliam and Bernhard Riegl. "Contrasting shifts in coral assemblages with increasing disturbances" Coral Reefs Vol. 39 Iss. 3 (2020) p. 783 - 793 ISSN: 07224028
Available at: http://works.bepress.com/bernhard-riegl/230/