An increase in demand for high altitude ski runs will have a serious impact on the number and diversity of Alpine bird species, Italian scientists warn.
Skiing has a "significant" impact on Alpine birds, scientists say
As winter snowfall at lower levels becomes less reliable, ecologists fear the demand for higher ski slopes will put pressure on the birds' habitat.
The team of researchers found a marked decline in bird numbers around ski runs when compared to natural grasslands.
The findings are published in the Journal of Applied Ecology.
Antonio Rolando, from the University of Turin, said: "Winter sports represent a potentially serious threat to the conservation of wildlife habitat in the Alps."
Writing in the paper, Professor Rolando described treeless areas at high altitudes as having an increased value as wildlife habitat because of the encroachment of human developments at lower levels.
"But they are affected and increasingly threatened by ski resorts," he wrote, "in particular by the construction and enlargement of ski pistes."
Professor Rolando and colleagues examined seven grassland locations in the western Italian Alps over two summers to assess the impact of skiing on Alpine bird populations.
The team focused their study on three types of habitat: recently constructed ski runs, grasslands near to ski runs, and habitats far away from any slopes.
The team reported that it found "significant differences".
"Plots located in natural open habitats supported the greatest bird species richness and diversity... whereas those set in the ski pistes had the lowest values."
Professor Rolando said the findings raised a number of worries: "More than one quarter of the 33 species in this study, including the rock partridge, red-billed chough and wheatear, are classified as species of European conservation concern."
As winter snowfalls became less reliable at lower altitudes, Professor Rolando said that pressure to develop new runs in semi-natural habitats at higher altitudes would only increase.
A report published in December warned that some Alpine ski resorts would become unviable within decades as a result of a warming climate.
The study by the Organisation for Economic Co-operation and Development (OECD) said sufficient snow was likely to become a thing of the past on lower-lying slopes.
Lack of snow could force ski resorts further up the slopes
An OECD official added that a number of Swiss banks were already refusing to finance resorts below 1,500m (4,900ft).
At the start of this year's skiing season, many resorts had to postpone their openings and the main ski races were cancelled because of a lack of snow.
If the industry headed further up the slopes to build new runs, the researchers said that developers should adopt environmentally sensitive practises to limit damage to the fragile habitat.
Professor Rolando suggested measures such as removing rocks and only levelling the roughest ground surfaces in order to preserve as much of the soil and natural plants as possible.
Once the revegetation of the piste had been achieved, the balance between skiers' safety and a suitable habitat for birds could be maintained by targeted pruning and cattle grazing, he added.
Further studies on the impact of winter sports on the Alpine environment would help establish a threshold within which future developments could be sustained without irreversible damage, he concluded.