Before disembarking at Grytviken, the Director of the South Georgia Heritage Trust came on board to talk about the challenges and successes of habitat restoration on the island. They’ve got a seriously impressive record.
I’ve mentioned the reindeer, but of course they’re fairly big and slow-moving. Once the decision had been taken to eradicate them, it was a matter of keeping shooting. (I didn’t have a decent belt with me, and along with another voyage crew member, had half-hoped for a reindeer skin belt to be picked up in the Grytviken Museum Shop, but sadly it was not to be.) There are reindeer trophies in abandoned sheds (as here at Ocean Harbour) and skeletons dotted around the island, but the animals themselves are gone.
Rats, on the other hand, are notoriously difficult to eliminate once they are established. This is true in many island environments as they are so adaptable, omnivorous and fast-breeding. South Georgia has been particularly vulnerable for two reasons. Its wildlife, like the better known New Zealand ground-nesting birds, is un-adapted to such a predator. And the tussac grass is a fantastic environment for rodents, with hidden tunnels, warmth and water. Many smaller birds have really suffered, such as prions, pin-tailed ducks and pipits. By the mid-noughties, it seemed that the once common pipit, the world’s most southerly songbird, had stopped nesting on the main island altogether, while the smaller offshore islands were vulnerable to further invasion.
South Georgia presents some unique challenges for such a programme. It is large of course, and much of it is unvisited. The winds are so extreme that finding pilots was really hard: eventually they mostly came from Aotearoa, a place with some experience of flying in really difficult weather. (I used to fly in and out of Wellington every week: even the scheduled passenger flights are white-knuckle events.) The ecology is delicate and the protection of indigenous species really important as so many are themselves endangered.
The island also faces a big time pressure. Until recently the rats were constrained by ice: even the most ambitious rodent finds crossing miles of glacier a bit of a challenge. But, as everywhere, the South Georgia glaciers are retreating. This picture, a screen shot from the site of Prof Mauri Pelto, a senior American glaciologist, highlights the retreat of the Neumayer glacier, which is not untypical. He says, based on analysis of NASA satellite material, ‘Landsat Image from 1999 to 2014 indicates retreat of 4800 m from the red to the green arrow , this is 320 m/year.’ As the ice disappears, the rats can spread. The Heritage Trust knew that it needed to act sooner rather than later before the rats got into even more of the island.
In 2011, SGHT set about eradicating the rats, using charitable support from the United States, starting with a big area around Grytviken itself. Helicopters spread bait using a spinning underslung bucket, and it was spread by hand in whaling stations and coves. The poison was specially designed for the local ecology to ensure minimal risk of effects on other species. The poison makes the rats photophobic, so they die underground, reducing the risk of scavengers, such as skuas, eating the bodies and being poisoned themselves. About 300 tons of bait has been used in the project.
They have now undertaken three phases covering all of the island, with continuing charitable help and support from the British Antarctic Survey. The last phase, in the southern part of the island, though the smallest area, was in some ways the hardest. 2015 was a bad year for storms and 150 knot winds destroyed one of their three precious helicopters, fortunately while it was on the ground.
The next, and hopefully final phase is the monitoring. The intention is to monitor for four and a half years (rather than the usual two) because the area is so large and changing fast. The first big push will be in 2017 when the Trust aims to get to many of the remotest area to search for rat-sign. They have successfully won money from the Darwin Plus initiative but of course need to raise more. You can easily donate on their site. (I did.) In the meantime, as I said yesterday, travelers visiting remote areas are themselves important eyes and ears for the project. So far, just one year on from the last phase, the signs are good, with no evidence of rats being reported.
Don’t just take my word for this impressive achievement either. The Dundee Professor, Tony Martin, who runs the project was named Conservationist of the Year for his work on South Georgia. The ultimate success, of course, is that pipits are breeding again on the main island, as this BBC picture of a nest at Schleiper Bay celebrates. Some good news in a world growing more dangerous by the day.