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Antarctica’s ice-free islands set to grow (hindu)

Until now the impacts of climate change and associated ice melt on bidoversity have been overlooked

Scattered within the vast frozen expanse of Antarctica are isolated ice-free nooks — nunataks (exposed mountain tops), scree slopes, cliffs, valleys and coastal oases — which cover less than 1% of the area, but support almost all of the continent’s biodiversity.

But by the turn of the century these ice-free islands could grow by over 17,000 sq.km (a 25% increase) due to climate change, according to a paper published in Nature.

While this may sound like good news for Antarctica's biodiversity that is likely to find larger habitats, “it is not known if the potential negative impacts will outweigh the benefits,” the authors say.

Invasive species


As ice-free islands expand and coalesce, biodiversity could homogenise, less competitive species could go extinct and ecosystems destabilise from the spread of invasive species, which already pose a threat to native species, says the paper.Much life thrives in Antarctica's ice-free pockets: small invertebrates (nematodes, springtails, and tardigrades) vascular plants, lichen, fungi, mosses and algae. They also serve as breeding ground for sea birds (including the Adelie penguins) and elephant seals.

One of the biggest threats from an increase in ice-free area appears to be the spread of invasive species, lead author Jasmine R. Lee from School of Biological Science at the University of Queensland, Australia, told The Hindu in an email. “The species that will lose will most likely be those that are not very competitive and can’t cope with the invasive species,” said Dr. Lee

Newly exposed habitats have already been colonised by invasive species in the Antarctic Peninsula, the paper points out. “Rocks recently exposed by snow melt have been subsequently colonized by Rhizocarpon lichens [and]... the invasive grass Poa annua has colonized new ice-free land near Ecology Glacier,” the paper notes.

The greatest change in climate is projected for the Antarctic Peninsula by the end of the century, and more than 85% of the new ice-free area is believed to occur in the north Antarctic Peninsula.

While considerable research has been directed towards the impact of climate change on melting Antarctic ice sheets and consequent sea level rise, “until very recently, the impacts of climate change and associated ice melt on native Antarctic biodiversity have been largely overlooked,” says the paper.

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