Antony Gormley's world tour continues: this stop, the Alps

hHgh on a hill was a lonely Gormley, layee odl, layee odl, lay-ee-o... As Maria might have trilled had she spotted the solitary, watchful figure, his feet planted firmly in grass and edelweiss, his gaze directed balefully out over the snowy peaks of the Alps. In fact, this Gormley is far from lonely. He's one of 100 identical figures, cropping up across the mountains of Vorarlberg in west Austria, like so many cast-iron von Trapps.

Antony Gormley has landed in Austria. His new work, Horizon Field, is his most sprawling to date, covering an area of 150 sq km. Some of the figures are clustered in groups, others are solitary. They perch on cliff-tops, rust-coloured bodies etched against a periwinkle-blue sky. They balance perilously on slopes of scree. Some peek over the brows of hills, their feet buried in snowy slippers. Others sun themselves in grassy alpine fields.

This is a new, dramatically rural environment for the sculptures which, prior to this, have been rather urban creatures. Thirty-one of them materialised on London's South Bank in 2007 – a punctuation mark in the flow of commuters over Waterloo Bridge, here, an alarming, suicidal sight on the rooftop of the Shell Building, there. In March, they flew over to New York to land on a parapet on the 26th floor of the Empire State Building and outside the Flatiron Building, among other places. Their naked skyscraper antics stopped traffic in a city still grieving its 9/11 dead. In both cities, the sculptures loomed, watching over the passive crowds, silently willing them to look up once in a while. They were just there – depending on your levels of metropolitan paranoia, a benevolent or sinister addition to the skyline and sidewalks.

This new Austrian tribe demands more active engagement from the viewer. Scattered across a vast plain, the tops of their bald heads make a horizontal line at 2,039m above sea level, "an altitude that is readily accessible but, at the same time, lies beyond the realm of everyday life". While the odd lonely goatherd may stumble across them, most of the figures are only accessible by means of a map, a 30-minute cable car ride and a hike. To reach others, you'll need skis.

So embedded are the figures in the landscape, the artist has already forgotten where some of them are. "I know where they are conceptually, but I'm as lost as the next man when it comes to actually finding these things," he admits. That's unlikely to deter packs of tourists from embarking on the Gormley rambling tour when the work is officially unveiled next month. "It's going to be a very annoying attraction and will involve an enormous amount of very fruitless walking and sweat," says Gormley. "At the same time, if this is the catalyst for getting people off their arses, then it's a good thing."

The Gormley body exercise plan? Perhaps. As he prepares to turn 60 in August, the exhibitionist artist has hired a personal trainer (a dancer called Julian) to tune his body for the rigours of making his work. His sculptures, it seems, have started to sag. "They've got fatter, basically – as is the way of bodies. I suppose there's always some vanity involved in these things."

The commission from the Kunsthaus Bregenz has been a typically physically challenging five-year project, starting with a summer spent looking for sites. By day, Gormley roamed the hills with his wife, Vicken ("my long-suffering partner in life and art"). By night, he slept on the top floor of a hay barn, "with cows and cheese below". Endless negotiations with local farmers, ski-lift operators, hunters, environmental agencies and avalanche advisers followed. Then came the heavy work. The 100 figures were brought over from Calabria in Italy where they had been installed among 8.5 hectares of Roman remains as the 2006 work Time Horizon. Each figure weighs 630kg and had to be hauled up the slopes on Ski-doos or dropped from helicopters. Fifteen mountain rescue teams helped out while the Austrian army were drafted in to dig the foundations. "They were strong and good, hard working and disciplined. I'd like to use the army more regularly for my projects," says Gormley. "They do these silly training exercises where they ruin perfectly good forests with tanks – this is more creative."

The work will remain in place until spring 2012. Dwarfed by the majesty of the mountains – they are "no bigger than the average-sized boulder" up there – and at the mercy of the elements, there's a new vulnerability to the familiar figures. Deliberately so, says Gormley. "I see this as an environmental project. It's asking where does the human being fit in the scheme of things? If there are six billion years left for the great nuclear reactor at the centre of our solar system to carry on producing energy, how long will homo erectus in its modern form participate in the evolution of life on this planet? We could be out of the door very soon."

As well as acting as mute, impassive markers in space and time, standing stones for the 21st century, they are also, irrefutably, yet more Gormleys. The artist's global domination continues. "They're separate from me. I don't identify with them at all," he demurs. "I am simply trying to identify human spaces in space at large. This is my material. It's not particularly special but it's what I've got. Yes, I'm leaving these industrial clones of myself. But they're not actually me." Austria will be the last stop on the tour. "We've done enough now. These life-like forms have had a good outing. It's time for them to go, to be dispersed or buried or something."

Meanwhile, the Gormley show rolls on with exhibitions in Paris and Rome, a new 25m-high, 60-tonne sculpture in Amsterdam and a high-profile hotel extension in London, to name but a few projects. And there are still more corners of the Earth to be populated. "I like deserts, I'd like to do something there. And I haven't quite exhausted my fascination with water yet. I've done a salt lake, but I haven't done a freshwater lake..." Watch this space – there'll probably be a Gormley in it before long.

kunsthaus-bregenz.at