Climate change risk to islands under-estimated

Climate change risk to islands under-estimated.

Decades of work to create safe island havens for some of the world’s rarest species could be undone if sea levels rise as high as climate scientists predict, according to a new study.

Decades of work to create safe island havens for some of the world’s rarest species could be undone if sea levels rise as high as climate scientists predict, according to a new study.

Researchers say conservation projects on islands involving pest eradications and translocation of endangered species could be undone because many are low-lying and in danger of being submerged by sea level rises of up to 2.3 m by 2100.

The study estimates up to 20,000 islands globally could be entirely submerged threatening hundreds of endemic species with extinction. Of 604 islands where invasive species have been eradicated, 26 are predicted to be completely inundated at a sea level rise of 1m.

“New Zealand has led the world in pest eradications and translocations for decades, but with impending climate change, we will need to shift our focus to conservation programmes on larger islands such as Rakiura (Stewart I) and Aotea (Great Barrier I), and the New Zealand mainland,” says Dr James Russell of the University of Auckland’s School of Biological Sciences, co-author of the study involving researchers from the University of Paris Sud and Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO).

As well as rising sea levels, vulnerable species face a predicted increase in the number and intensity of cyclones, greater tidal ranges – causing more seawater flooding – and changing climatic conditions leading to habitat loss. And unlike their mainland counterparts, island species have nowhere to go.

“It may be that eventually we will be faced with some tough decisions about whether we move species in order to save them or whether we do nothing and let them go extinct,” Dr Russell says. “But one of the things we need to start thinking about now is which species are most at risk from rising sea levels and the options for saving them.”

Climate change and the looming threat from rising sea levels will need to be a key consideration for future island restoration work and it may be that larger islands at less risk of submersion will have to become a higher priority for invasive species eradication, the study concludes. The paper appears in this month’s issue of the prestigious international journal Trends in Ecology & Evolution. DOI: http://dx.doi.org/10.1016/j.tree.2014.01.001

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