Formerly ‘pristine’ South Atlantic Islands under threat from rafts of plastic bringing alien species, scientists warn

'I suspect that plastics are responsible both for the direct transfer of alien species and also for the spread of them when they arrive'

A massive spike in plastic washing up on the shores of remote South Atlantic islands has sparked concerns that it is bringing destructive alien species to the once pristine environments.

In British overseas territories including Ascension, St Helena and the Falkland Islands, the amount of plastic waste it 10 times greater than it had been a decade ago, scientists have found.

As they are considered biodiversity hotspots, researchers are concerned that their unique wildlife is at risk not only from choking on fragments, but also from the invasive species these plastics appear to be bringing with them.

As plastics break down in the ocean, the rough, pitted surfaces that they form become a perfect environment for small creatures to live on, meaning they often become floating rafts.

Alien species arriving on plastic can range in size from tiny microbes to larger creatures like crustaceans.

However, animals as large as iguanas have been observed rafting on debris that floats in the sea.

“Lots of things can settle on it, native and non-native, and anything that settles anywhere can travel anywhere – because as we know plastics have been picked up that have travelled the world ocean, they can go anywhere,” Dr David Barnes from the British Antarctic Survey, who led the study, told The Independent.

“I myself have found non-natives on plastic.”

It is difficult to know exactly how the non-natives arrived as they could have arrived on ships and later colonised the plastic.

However, Dr Barnes thinks plastics are “a very considerable problem for alien dispersal”.

He said: “I suspect that plastics are responsible both for the direct transfer of alien species, and also for the spread of them when they arrive at places."

Publishing their findings in the journal Current Biology, Dr Barnes and his team wrote that they found plastic waste was found littering the bottom of the sea around the islands and the beaches themselves, where it was highly prevalent.

They found up to up to 300 items per metre of shoreline on the East Falkland and St Helena, including areas that have been officially set aside for special protection.

“It’s all very well saying we have got this massive marine protected area around the UK overseas territories… But ultimately that doesn’t deal with any of this threat,” Dr Barnes said.

To stop plastic ending up on the islands, he added that industry and society must work together to find solutions that prevent it ending up in the ocean in the first place.

“These islands and the ocean around them are sentinels of our planet’s health. It is heart-breaking watching albatrosses trying to eat plastic thousands of miles from anywhere,” said Dr Andy Schofield, a biologist from the RSPB, who was also involved in the research. “This is a very big wake up call. Inaction threatens not just endangered birds and whale sharks, but the ecosystems many islanders rely on for food supply and health.”