What of the Future? - Climate Change Impacts on Freshwater Ecosystems - page 298

High mountain zone
The high mountains had always been iconic in Europe for the photographic
panoramas of snow-capped peaks rising to a blue sky, the ski slopes in winter and
the alpine meadows studded with flowers in summer, let alone the images from
the world's most viewed film The Sound of Music . Set deep in the mountains, the
River Ppartnov had a small catchment of 300km 2 that epitomized the region.
Winter temperatures in the early 21st century averaged around freezing point
and in summer about 25 °C, but changed a great deal from the tips of the highest
peaks at 3,000m to the valley floor 2,400m below. Precipitation likewise was
much higher, 900 mm, on the mountains but only 400 mm in the valley. Much of
the water ran off in streams because much of the snow melted in spring and for
some years the mountain glaciers had been retreating from their much greater
extents a century or more before, when they had challenged the early visiting
mountaineers. Evergreen forests of spruce and fir, with the deciduous larch, gave
out at an altitude of 2,000 m to grasslands and tundras, where marmots and, on
the rocky heights, the rarer ibex could be seen. An occasional brown bear still
wandered through the forest and fed on berries at the tree line. Small farms,
usually only a few hectares in area, kept some cows and grew grass and potatoes
or a small plot of grain, and even some maize up to 1,200 m and on the flat valley
floor. Tourists came for winter sports and in summer to walk up to the small tarns
in the corries and along the lively rivers. They spent their euros on woodcarvings
and embroidery and schnapps in the picturesque town in the valley, where the
river had been long embanked and canalized to preserve the scarce land from any
flooding. The flood plain had prehistorically occupied the entire valley floor. Just
above the town the river had also been dammed to provide some local hydropower,
not least to drive machinery at the local sawmill.
By the mid-20th century, the precipitation had not changed much but had
shifted towards a greater winter snowfall and a much drier summer as temperatures
had increased. The snow line had moved some 200 m upwards, leaving the lower
ski slopes abandoned and the glaciers below the peaks had noticeably retreated.
Much more water was cascading down the streams in spring, and the forests
sometimes resounded to the crash of large boulders moving as the force of the
water recarved the channels. The forest too had changed with dwarf pine, beech
and other deciduous trees starting to take over from the previous evergreens. The
water was still relatively cool and the arctic charr and brook trout still persisted
but there had been some subtle chemical changes as higher temperatures had
increased the weathering of the rock debris ground previously by the glacier
movement. Levels of some heavy metals had risen and the local authorities had
condemned the water for direct human supply and for stock watering, so that
farming patterns had changed and the sound of cow bells was no longer heard
as it had been when they came in for milking in the evenings. Farming was
under pressure in any case, as overheads had increased in a global market that
did not favour small operators, despite the generally increasing world shortage of
food. Tourism still thrived, for the higher slopes were still covered with snow
for several months and a refrigeration plant had been built, based on a small