Contrasting shifts in coral assemblages with increasing disturbances

Pratchett, Morgan S., McWilliam, Michael J., and Riegl, Bernhard (2020) Contrasting shifts in coral assemblages with increasing disturbances. Coral Reefs, 39. pp. 783-793.

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Abstract

Increasing incidence of major disturbances is contributing to extensive and widespread coral loss, thereby undermining the biodiversity, structure and func- tion of reef ecosystems. The composition of coral assem- blages 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 spe- cies with slow growth (massive and columnar Porites). Inter-decadal shifts in the coral assemblages across four locations suggest that a high frequency of moderate dis- turbances 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 distur- bance 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.

Item ID: 63856
Item Type: Article (Research - C1)
ISSN: 1432-0975
Keywords: climate change; coral reefs; community shifts; modelling
Copyright Information: © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Funders: American Australian Association, Australian Research Council (ARC)
Projects and Grants: AAA Sir Keith Murdoch Fellowship, ARC Centre of Excellence for Coral Reef Studies CE140100020
Date Deposited: 04 Aug 2020 04:48
FoR Codes: 06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 60%
05 ENVIRONMENTAL SCIENCES > 0501 Ecological Applications > 050101 Ecological Impacts of Climate Change @ 40%
SEO Codes: 96 ENVIRONMENT > 9603 Climate and Climate Change > 960307 Effects of Climate Change and Variability on Australia (excl. Social Impacts) @ 30%
97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 70%
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