Growth form-dependent response to physical disturbance and thermal stress in Acropora corals
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Growth form-dependent response to physical disturbance and thermal stress in Acropora corals S. Muko • S. Arakaki • M. Nagao • Kazuhiko Sakai
Received: 12 December 2011 / Accepted: 3 October 2012 / Published online: 12 October 2012 Ó Springer-Verlag Berlin Heidelberg 2012
Abstract To predict the community structure in response to changing environmental conditions, it is necessary to know the species-specific reaction and relative impact strength of each disturbance. We investigated the coral communities in two sites, an exposed and a protected site, at Iriomote Island, Japan, from 2005 to 2008. During the study period, a cyclone and thermal stress were observed. All Acropora colonies, classified into four morphologies (arborescent, tabular, corymbose, and digitate), were identified and tracked through time to calculate the annual mortality and growth rate. The mortality of all Acropora Communicated by Biology Editor Dr. Mark Vermeij
Electronic supplementary material The online version of this article (doi:10.1007/s00338-012-0967-z) contains supplementary material, which is available to authorized users. S. Muko Faculty of Fisheries, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan S. Muko PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan S. Muko K. Sakai (&) Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, 3422 Sesoko, Motobu, Okinawa 905-0277, Japan e-mail: [email protected] S. Arakaki Amakusa Marine Biological Laboratory, Kyushu University, Amakusa 863-2507, Japan M. Nagao Institute of Geology and Geoinformation (IGG), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8567, Japan
colonies in the protected site was lower than that in the exposed site during the period without disturbances. Extremely higher mortality due to bleaching was observed in tabular and corymbose Acropora, compared to other growth forms, at the protected sites after thermal stress. In contrast, physical disturbance by a tropical cyclone induced the highest mortality in arborescent and digitate corals at the exposed site. Moreover, arborescent corals exhibited a remarkable decline 1 year after the tropical cyclone at the exposed site. The growth of colonies that survived coral bleaching did not decrease in the following year compared to previous year for all growth forms, but the growth of arborescent and tabular remnant corals at the exposed site declined severely after the tropical cyclone compared to previous year. The delayed mortality and lowered growth rate after the tropical cyclone were probably due to the damage caused by the tropical cyclone. These results indicate that the cyclone had a greater impact on fragile corals than expected. This study provides useful information for the evaluation of Acropora coral response to progressing global warming conditions, which are predicted to increase in frequency and intensity in the near future. Keywords Bleaching Tropical cy
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