Matt Ridley from the UK: The ecological restoration of South Georgia

The success of a bold bid to rid a subantarctic island of rats and deer - how South Georgia's environment has been repaired.

In claiming the Falklands, the Argentinian government also claims South Georgia, even though it is 700 miles further away from its coast, was unambiguously claimed by Captain Cook when uninhabited, and is run as a separate territory by the British government. Indeed, as I found out last week when I was lucky to visit courtesy of the island’s government, it is a place where something truly astonishing has been achieved in the world of conservation.

In summer South Georgia teems with wildlife: four million fur seals crowd its shores, elephant seals are piled in somnolent heaps on beaches, penguin colonies boggle the mind in their scale, the cliffs and slopes are alive with more than 50 million albatrosses, prions and petrels, while whales once again blow in the surrounding ocean. This wealth of wildlife is the result of changing economic incentives plus regulation— to stop sealing, whaling and penguinning and to control fishing.

But a few years ago, conservationists decided that protection was not enough. Rats and reindeer also thrived on the island, introduced by sealers and whalers more than a century ago. The rats had driven certain birds extinct on the main island, while the reindeer had altered the vegetation, suppressing some indigenous plants. Around the world invasive species such as these are the source of more extinctions than any other cause.

In an unusual combination of private-public enterprise, the South Georgia Heritage Trust and the government of South Georgia decided that every rat and every reindeer must go. This was almost absurdly ambitious: in the 1980s one expert wrote about the prospect of rat eradication on South Georgia: “regrettably, this is virtually impossible”. But the New Zealanders had pulled it off on the smaller Campbell Island and the Australians on Macquarie Island, so valuable experience existed. Bold people began to think it might be done on the much larger, colder and more mountainous South Georgia too.

A poison called brodifacoum, which is irresistibly tasty to rats, had been developed in Wisconsin; helicopter pilots had learnt to spread the bait from buckets slung below their aircraft (if necessary flinging it sidewise on to cliffs); and GPS allowed the choppers to ensure that they covered every square metre of the island and revisited those they had missed.

The trust raised £7 million, mostly from private sources, bought three helicopters, found skilled pilots and set to work. Led by Tony Martin, of Dundee University, they first tackled two large but fairly accessible peninsulas of the east coast, separated from the rest of the island by glaciers too large for rats to cross. Two years later they returned and did the western half of the island, and in 2014-15 they completed the eastern half. As feats of flying, logistics and digital mapping go, the achievement was unique.

Rat tracks in the snow vanished. To check that it had worked, monitoring devices have been spaced all around the island, with peanut-flavoured bait formulated in such a way as to show if it had been gnawed. To date there has been just a single breach when last summer, soon after two ships had berthed there, rat footprints were found by builders in the snow in the British Antarctic Survey station at King Edward Point. The area was blitzed with rat poison and no more signs were found.

The collateral damage was minimal. Predatory skuas suffered briefly from eating the poisoned rats, but their population has already bounced back. Mice lived in one part of the island and these too were exterminated.

The reindeer project began in 2012, funded by the government — it’s probably harder to raise donations for wiping out reindeer than rats. Led by Dr Jennifer Lee, the team first herded about 1,000 deer into a specially built corral on one peninsula, where they were humanely stunned and butchered to provide excellent steaks for the visiting cruise ships. A few had been previously removed alive to two ranches in the Falklands.

The remaining 6,000 reindeer were hunted down within two years by Norwegian deer stalkers. Last summer just 47 remained and were soon shot. This summer a single male has been found, spotted by Sarah Lurcock, the island’s museum director, on a camping trip in a remote spot. It was dispatched last week: conservation cannot be a sentimental business.

Keeping South Georgia free of alien pests is now an obsession. Visitors must have clean footwear and clothing, while every ounce of cargo brought onshore is inspected in a small room in a building that can be sealed in an emergency. It’s not just rodents that they are trying to keep out: earwigs have become a pest on the Falklands, whence supplies come. Every object — even every potato — that comes ashore is inspected, and broccoli and leeks are banned (their leaves are too good at concealing earwigs or soil).

The conservationists are now focusing on introduced plants, trying to spray them with herbicide wherever possible. Some such as dandelions are too well established and will have to stay, but others have not yet gained much of a foothold and should soon be eradicated — though seeds may remain for some time.

South Georgia may be logistically difficult, but it is politically simple. The population is a handful of scientists, the government a handful of multi-tasking officials under the commissioner, Colin Roberts, who is also the governor of the Falklands. In Britain if you propose radical measures to get rid of (say) the signal crayfish, an American species that has ruined the insect life, fish life and water quality of my local river, you enter a bureaucratic maze of cautious regulation and delay. We need to be bolder.

Spraying, shooting and poisoning are not what most people think of as conservation. But South Georgia teaches the lesson that wildlife preservation is not just a matter of slapping on legal protection but requires active intervention to eradicate invaders. Rat eradication has been tried, so far without success, on Henderson, a remote Pacific island whose birdlife has suffered. Gough island, northeast of South Georgia, has an epidemic of mice, which gnaw young albatrosses to death and is next on the list. We have a duty to undo what we have done wrong to nature.

Matt Ridley, a member of the British House of Lords, is an acclaimed author who blogs at www.rationaloptimist.com.