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Seabirds and Coral Reef Health

Seabirds and Coral Reef Health

New scientific results highlight the link between large seabird colonies and healthy coral reef with high growth rates.  

To read more on Island Conservation website: https://www.islandconservation.org/seabirds-enhance-coral-reef-growth-new-scientific-research/

Read the original study here: https://www.nature.com/articles/s41598-019-41030-6

Young Booby on Temoe Island (Gambier Archipelago) – SOPManu

About the study

Colonies of Acropora formosa were sampled from Namenalailai (hereafter Namena) – a remote island in Fiji Archipelago. This island has abundant nesting seabirds and a large marine protected area. Then samples of coral were taken from Cousteau, a neighboring island with a similar environment, also a marine protected area but with much fewer nesting seabirds.

These samples, both Acropora formosa coral, were first tested for nutrient content, specifically nitrogen. Then samples of coral from Namena were planted within Cousteau coral reefs and vice versa in order to analyze growth rates within both coral samples. The changes in these transplanted reefs were then monitored for one year.

The results

This study shows that reef-building corals grown near a large seabird colony exhibited growth rates up to four times greater than conspecifics from the same area that were transplanted distant from seabird nutrients.

Seabirds are vital to coral ecosystem balance because when they nest on islands they leave behind guano filled with nutrients such as nitrogen. Not only does seabird nutrient positively affect corals directly but it also contributes to symbiotic relationships within the coral ecosystem.

Conservation and management implications

Seabird populations are becoming increasingly threatened worldwide, one of the biggest factors being the presence of invasive species. Large seabird colonies often reside on islands where they are unable to escape. The major threats for them are invasive predators including such as rats, mice, pigs or feral cats. Removing invasive species from islands allow seabird populations to flourish. It also creates healthier coral environments. Abundant coral reefs bring far-reaching benefits such as higher rates in biodiversity, mitigation to climate change, and better stability in fish populations.

Protecting our seabird worldwide populations from human disturbance or invasive species should be a top conservation priority. 

Polynesian Storm-petrel @Ray Pierce (listed as EN on IUCN Red List)
Polynesian Storm-petrel @Ray Pierce (listed as EN on IUCN Red List)