Variable responses of benthic communities to anomalously warm sea temperatures on a high-latitude coral reef

Tom C L Bridge; Renata Ferrari; Mitch Bryson; Renae Hovey; Will F Figueira; Stefan B Williams; Oscar Pizarro; Alastair R Harborne; Maria Byrne

doi:10.1371/journal.pone.0113079

Variable responses of benthic communities to anomalously warm sea temperatures on a high-latitude coral reef

PLoS One. 2014 Nov 26;9(11):e113079. doi: 10.1371/journal.pone.0113079. eCollection 2014.

Authors

Tom C L Bridge¹, Renata Ferrari², Mitch Bryson³, Renae Hovey⁴, Will F Figueira⁵, Stefan B Williams³, Oscar Pizarro³, Alastair R Harborne⁶, Maria Byrne⁷

Affiliations

¹ ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, Australia; Australian Institute of Marine Science, PMB #3, Townsville MC, Townsville, QLD, Australia.
² School of Biological Sciences, University of Sydney, Sydney, NSW, Australia; Australian Centre for Field Robotics, School of Engineering, University of Sydney, Sydney, NSW, Australia.
³ Australian Centre for Field Robotics, School of Engineering, University of Sydney, Sydney, NSW, Australia.
⁴ School of Earth and Environment and Oceans Institute, University of Western Australia, Crawley, WA, Australia.
⁵ School of Biological Sciences, University of Sydney, Sydney, NSW, Australia.
⁶ Marine Spatial Ecology Laboratory and ARC Centre of Excellence for Coral Reef Studies, School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia.
⁷ School of Biological Sciences, University of Sydney, Sydney, NSW, Australia; School of Anatomy, University of Sydney, Sydney, NSW, Australia.

Abstract

High-latitude reefs support unique ecological communities occurring at the biogeographic boundaries between tropical and temperate marine ecosystems. Due to their lower ambient temperatures, they are regarded as potential refugia for tropical species shifting poleward due to rising sea temperatures. However, acute warming events can cause rapid shifts in the composition of high-latitude reef communities, including range contractions of temperate macroalgae and bleaching-induced mortality in corals. While bleaching has been reported on numerous high-latitude reefs, post-bleaching trajectories of benthic communities are poorly described. Consequently, the longer-term effects of thermal anomalies on high-latitude reefs are difficult to predict. Here, we use an autonomous underwater vehicle to conduct repeated surveys of three 625 m(2) plots on a coral-dominated high-latitude reef in the Houtman Abrolhos Islands, Western Australia, over a four-year period spanning a large-magnitude thermal anomaly. Quantification of benthic communities revealed high coral cover (>70%, comprising three main morphospecies) prior to the bleaching event. Plating Montipora was most susceptible to bleaching, but in the plot where it was most abundant, coral cover did not change significantly because of post-bleaching increases in branching Acropora. In the other two plots, coral cover decreased while macroalgal cover increased markedly. Overall, coral cover declined from 73% to 59% over the course of the study, while macroalgal cover increased from 11% to 24%. The significant differences in impacts and post-bleaching trajectories among plots underline the importance of understanding the underlying causes of such variation to improve predictions of how climate change will affect reefs, especially at high-latitudes.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animal Distribution / physiology*
Animals
Anthozoa / physiology*
Climate Change
Coral Reefs*
Ecosystem
Seaweed / physiology*
Temperature
Western Australia

Grants and funding

This project was funded by the Great Barrier Reef Foundation's Resilient Coral Reefs Successfully Adapting to Climate Change research and development program in collaboration with the Australian Government. Additional support was provided by The Australian Research Council (ARC) and Australia's Integrated Marine Observing System (IMOS), funded by the Department of Innovation, Industry, Science and Research through the National Collaborative Research Infrastructure Scheme and the Education Investment Fund, and the Marine Biodiversity Hub, a collaborative partnership supported through funding from the Australian Government's National Environmental Research Program (NERP). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.