Disappearing wild goats trouble scientists

It is known as Gran Paradiso - the Great Paradise - and for decades Italy's oldest national park has protected the extraordinary wealth of wildlife that inhabits its alpine peaks, high passes and forests.

But the huge reserve has become anything but an ideal habitat for its most emblematic species - the ibex.

Italian conservationists are mystified by a precipitous decline in the species, Europe's largest alpine wild animal.

The population of the mountain goat, distinctive for its long backward-curving horns, has halved in recent years, with 75 per cent of young animals failing to reach maturity.

The latest census, taken last month, estimated that the ibex population had fallen from 5000 in the early 1990s to 2500.

Experts are baffled by the fact that whatever is killing off young ibex does not affect the adult animals, which can reach up to 100kg in weight.

"There has been no decline in the rate of survival among adult ibexes. It is just the young ones who are dying," said Dr Bruno Bassano, the national park's chief veterinarian. "The reason for it remains a mystery."

Biologists from two Italian universities - Pavia and Sassari - and a Canadian university, Sherbrooke in Quebec, are working on several theories as to what could be to blame.

"The first hypothesis is that the young ibex are dying as a result of a pathogen but one would have thought that would also affect the chamois in the park, whereas in fact they seem fine," said Bassano.

A second theory is that a series of mild winters over the past 15 years - possibly linked to global warming - has allowed old female ibexes to survive beyond their normal life expectancy. These biologically weaker animals have given birth to frail offspring unable to withstand the rigours of living in such challenging terrain.

The third possibility is that a series of long, hotter than average spring seasons resulted in grass growing much earlier than usual, so that by the time it was needed as food by young ibex its nutritional value was drastically reduced.

The population decline is all the more troubling because the ibex is the official symbol of Gran Paradiso, a 700sq km region of remote valleys and serrated ridges north of Turin, close to the border with France.

In 1922 the region was declared the country's first national park.

Gran Paradiso was, at the time, the last stronghold of the ibex in Europe.

THE ALPINE IBEX

What: A species of wild mountain goat in the European Alps, living in rough terrain at a height of 2000-4500m on vegetation. Related ibex species live in Spain and the Middle East.
Size: Adult male goats reach 1m and 100kg. Their horns can grow to 1m. Female goats are about half the size.
Predators: Wolves, lynxes, bears and foxes.