Rapid recovery of a coral reef at Darwin Island, Galapagos Islands
Surveys at Darwin Island in 2006 and 2007 have demonstrated that this northernmost Galapagos Islands coral reef has recovered significantly since the 1982–3 El Niño event. When first surveyed in 1975, this structural reef exhibited actively accreting frameworks of pocilloporid and poritid corals. Th...
| Main Authors: | , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
2009
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| Subjects: | |
| Online Access: | http://aquaticcommons.org/21423/ http://aquaticcommons.org/21423/1/GR_66_p6-13.pdf |
| Summary: | Surveys at Darwin Island in 2006 and 2007 have demonstrated that this northernmost Galapagos Islands coral reef has recovered significantly since the 1982–3 El Niño event. When first surveyed in 1975, this structural reef exhibited actively accreting frameworks of pocilloporid and poritid corals. The coral suffered severe mortality in 1983, resulting in the near total loss of pocilloporids and extensive partial mortality of poritid corals. Large sections of the reef had not recovered by 1992 and dead frameworks were subject to bio-erosion, although small numbers of sexual recruits of pocilloporid corals and numerous recruits plus regenerating patches of Porites lobata were present in some areas. An increase in live coral cover and recruitment was apparent through 2000 and 2002. Recent sampling at three sites along the reef has demonstrated mean (± 1 SD) live coral cover of 21.9 ± 1.7 % with P. lobata as the predominant species. Pocillopora spp. were present, but not so abundant as in earlier surveys. In spite of moderate erosion by echinoid and fish grazers, much of the original coral framework remained intact, providing a substrate for coral regeneration and recruitment. Recovery can be attributed to the original reef structure remaining intact, asexual regrowth of surviving tissues and sexual recruitment of poritid corals from surviving source populations. |
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