Col de Tricot via Le Champel

3 points of interest

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  Lake

  Glacial lakes, trailblazing ecosystems

  Haute-Savoie's glaciers have lost 30% of their total surface area since 1850. The Bionnassay glacier here has retreated nearly 325m since the 1990s, creating a lake in the 2000s. Glacial retreat creates new lakes in some of the hollows where the glacier once stood. These new lakes are therefore still ‘dynamic’ and can give rise to hazards; they are constantly being created and then emptied. The de-glaciated surface is composed of up to 90% mineral zones (rock outcrops, moraine, scree), with the remainder made up of conifers, grassland, deciduous trees and lakes. In the Alps, scientists have modelled the expected emergence of between 200 and 900 additional lakes by 2100 on the new de-glaciated zones. (Bosson et al., Nature 2023). High mountain landscapes are changing, revealing new, rich and wild ecosystems!

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  Flora

  Silene acaulis

  It is an evergreen perennial ground cover plant. The leaves of Silene acaulis form a kind of moss carpet from which pink flowers with a short peduncle emerge. This plant can be seen from June to August. Despite being called acaulis (= stemless), this plant has a small, robust stem that can climb limestone and stony soils at altitudes of up to 2800 m!

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  Flora

  reen Alder (Alnus alnobetula): a valiant but dangerous coloniser

  A familiar sight in the steep ravines and slopes of the mid-mountain regions of the Alps and Corsica, Alnus alnobetula has the unique ability to bend under snow and even rockslides without breaking. It grows rapidly, taking just a few decades to transform a meadow into a dense forest. This prevents the seeds of other trees from sprouting, thus blocking the natural evolution of the Alpine ecosystem. This plant improves soil quality: Green alder retains nitrogen in the soil and also strengthens the soil that is vulnerable to landslides thanks to its robust roots. However, Green Alder is also considered to be a threat to ecosystems: it colonises environments lacking other plant species by overgrowing fields that could be suitable for grazing and spreads nitrogen, nitrate and nitrous oxide, which in large quantities is harmful to the environment.