Interesting facts 

Pioneers on the Edge of the Glacier

The glaciers in the UNESCO World Heritage site have retreated a long way in the past few decades, as they have all over the Alps. The Unteraar glacier is now around 2,4 km shorter than it was in 1876, while the Great Aletsch glacier has actually lost over 3 kilometres since 1860. This is the beginning of the struggle for survival for plants in certain succession stages.


As the glaciers shrink, the ground they free is initially infertile, but it takes only a few years for the colonisation to start. The first to get a foothold are inconspicuous and extremely undemanding mosses and lichens; they pave the way for the first spots of colour in the greyish-brown terrain: alpine Toadflax, alpine Willow herb, yellow Saxifrage and other species gradually colonise the inhospitable realm, using an astonishing diversity of sophisticated strategies to fight for their survival on the edge of the glacier. These pioneers bring nutrients to the loose debris of the moraines, thus enriching the soil. The first pioneer plants gradually give way to bushes and then trees. It may be decades or even centuries before a forest takes root again. This evolution, known technically as succession, is particularly striking at the Great Aletsch glacier and the comprehensive research that has been done and the extensive follow-up literature help to understand what is happening. The Aletsch area has a remarkable botanic particularity to offer.