Rats gone: Tenfold increase in wedge-tailed shearwaters on 2 Seychelles' islands听
This latest study estimated 2,768 and 2,406 breeding pairs in 2016 and 2021. (Rainer Von Brandis, Save Our Seas Foundation)
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(海角在线免费) - The population of wedge-tailed听shearwaters听on D'Arros Island and St Joseph Atoll in Seychelles has increased听tenfold, according to the Save our Seas Foundation (SOSF), which highlighted a successful eradication of rats, in a paper earlier this year for the Marine Ornithology journal.
The project to eradicate rats was听undertaken in the year 2003听and the island was declared rat-free in 2005.
This statement is supported by a series of surveys and research papers on the birds. The original survey was done in 2009 by scientists led by Michelle Kappes, the 2017 survey was conducted by Danielle Keys,听and the 2021 survey was by current D'Arros research centre staff.
Invasive rats and mice inhabit 80听percent听of the听islands in the Indian Ocean region听and pose听a serious conservation threat to breeding seabirds. Rodents easily听prey on听eggs and chicks of nest-bound birds and,听in some cases,听even听brooding adult seabirds,听which听have not developed any sense of anti-predator behaviour.
"The result,听as seen on Marion Island, is that seabirds face local extinction. Without successful intervention on this sub-Antarctic island, scientists believe that 19 out of 28 bird species could be lost by 2030," said the Save Our Seas Foundation D'Arros Research Centre.
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| The population of wedge-tailed听shearwaters听on D'Arros Island and St Joseph Atoll in Seychelles has increased听tenfold.听(Save Our Seas Foundation, Rainer von Brandis)听Photo License:听All Rights Reserved听 听听 |
According to the chief executive of SOSF, James Lea, this latest study estimated 2,768 and 2,406 breeding pairs in 2016 and 2021, respectively, nearly 10 times larger than estimated in 2009.
"D'Arros has preventive measures in place to ensure that the biosecurity of goods transported to D'Arros is implemented at source, and in addition, they have pens at offload sites and traps set around the island that provide a second layer of security,"听said Lea.
顿补苍颈别濒濒别听碍别测蝉,听a researcher from Nelson Mandela University in South Africa, said,听"The shearwaters on D'Arros island make up the largest breeding population in the western Indian Ocean compared听to Madagascar, Mauritius, and the Comoros.听St.Joseph Atoll is one of the largest breeding colonies of wedge-tailed shearwaters in the western Indian Ocean听and Fouquet Island is home to most of them."
The researcher stated that St. Joseph Atoll represents as much as 16听percent of the total population of wedge-tailed shearwaters in the western Indian Ocean. As a result, these birds might also be repopulating D'Arros Island,听which lies two kilometres from the St Joseph Atoll, as birds find new nesting grounds nearby to avoid overcrowding on the atoll.听Scientists call this phenomenon a听'source population.'
Understanding听the听changes enables researchers and managers to prioritise the future and perhaps even look to safeguarding populations elsewhere.
The Save Our Seas Foundation said that given the importance of the area to these breeding seabirds, the long-term monitoring of wedge-tailed shearwaters can help guide researchers on conservation strategies.
At present D'Arros Island, which is a private island, is occupied by staff of the Save Our Seas Foundation D'Arros Research Centre and they continue to monitor the shearwater population and promote its conservation as part of their long-term monitoring programmes.听
