Ngederrak,  Lighthouse Reefs recover – study

Ngederrak, Lighthouse Reefs recover – study

  20 Apr 2018

A collaborative study between The University of Queensland, Marine Spatial Ecology Lab (MSEL), and Palau International Coral Reef Center (PICRC) shows recovery of the Ngederrak and Lighthouse reefs after extensive damages as a result of Typhoon Bopha.

Ngederrak and Lighthouse reefs have been through a couple of natural disasters. First, in 1998, the massive coral bleaching event severely impacted the reefs. Before this massive bleaching event, the reefs were healthy and thriving, providing home to branching corals. Unfortunately, after this bleaching event, the coral cover significantly decreased, resulting in rubble. As such, rubble is not a suitable place for coral recruits to settle, thus recovery was slow.

In 2006, the rubble had cemented together, providing a stable area for coral recruits to settle and grow, which led to a healthy recovery of corals, reaching more than 60% coral cover in 2012. However, later in 2012, Typhoon Bopha damaged the reefs along the east side of Palau, reducing coral cover to basically zero at Ngederrak and Lighthouse reefs.

Since 2012, researchers from MSEL and PICRC continued to monitor these two areas for recovery. The 2018 data shows good recovery at two sites within these area, south side of Ngederrak and Lighthouse Reef. In the northern area of Ngederrak, there is little evidence of recovery, which could be caused by natural barriers like current patterns and larval disbursement.

At the south side of Ngederrak, the coral cover is increasing and now has exceeded 10%. The amount of small coral colonies shows that the reef is recovering and is continuing to do so, as evidenced by these baby corals.   In Lighthouse Reef, the recovery rate is even greater than Ngederrak, with coral cover now at 30%.

The research at Ngederrak and Lighthouse reefs show that while some reefs have been severely impacted by natural disasters, there is a great potential for recovery, though it may take years to do so.  While we see good recovery, continued monitoring is necessary in case of other disturbances, like the Crown of Thorns Starfish (COTS), which can severely decimate coral reefs if not kept in check. (PR)