Recovery of an isolated coral reef system following severe disturbance, Scott Reef and Seringapatam, Timor Sea

Brief description

Benthic CoverPercentage cover of hard corals, soft corals and other benthic groups on the reef slope at Scott Reef and Seringapatam. During most years from 1994 to 2010, percentage cover was quantified along permanent transects (250 m) at each of 21 sites across seven regions of Scott Reef and Seringapatam.Size-structure and fecunditySize structure and reproductive output of Acropora assemblages on the reef slope at Scott Reef and Seringapatam. The longest linear dimension of Acropora colonies was measured along permanent transects of 200 m² for colonies >10 cm, and 50 m² for colonies Coral recruitmentRecruitment of Acropora corals on the reef slope at Scott Reef and Seringapatam. During most years from 1996 to 2010, terracotta settlement plates (n = 108) were deployed and collected across 18 permanent sites and six regions of Scott Reef and Seringapatam, one month either side of the mass coral spawning in Autumn each year.Coral survivalPost-bleaching survival of corals at Scott Reef and Seringapatam. Colonies (n = 5333) of branching (Acropora spicifera) and massive (Goniastrea retiformis/edwardsi) corals of all sizes were tagged and resurveyed in May each year, at eight sites across four regions of Scott Reef and Seringapatam. Coral reef recovery from major disturbance is hypothesised to depend on the arrival of propagules from nearby undisturbed reefs. Therefore, reefs isolated by distance or current patterns are thought to be highly vulnerable to catastrophic disturbance. Here, we show that on an isolated reef system in north Western Australia, coral cover increased from 9% to 44% within 12 years of a coral bleaching event, despite a 94% reduction in larval supply for six years after the bleaching. The initial increase in coral cover was the result of high rates of growth and survival of remnant colonies followed by a significant increase in juvenile recruitment as colonies matured. We show that isolated reefs can recover from major disturbance, and that the benefits of their isolation from chronic anthropogenic pressures can outweigh the costs of limited connectivity.

Lineage

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Notes

Credit
Gilmour, James, Dr (Principal Investigator)