1 - Saxifraga bryoides on bare rock

• On site weathering of minerals.

2 - Glacier forefield (Wildstrubel glacier, Swiss Alps)

3 - Left: fresh silt deposited from a glacier creek; right: border of an alpine sand dune (near the Pasterze glacier, Grossglockner, Austrian Alps).

• Release from mineral dust imported by wind (aeolic deposition) or run-off water (silt deposition) which together may accumulate up to 1 mm per year of dust and fine silt, commonly derived from open terrain such as glacier forefields (Fig. 2) and moraines. There are even sand dunes in some alpine areas (Fig. 3).

Alpine plants are commonly not short in mineral nutrients, because of the young age of soils and slope activity (Fig. 4). In old humic soils (Fig. 5) on relatively flat ground in humid climates, leaching (podzolisation, see slope processes and alpine soils) can, however, lead to the loss of essential nutrients. Disturbance of these sites (e.g. by digging a supply line or by ground animal activity, Fig. 6) can create long-lasting visible changes in plant cover (more lush appearance)

4 - Fresh mineral nutrients released by natural disturbance.

5 - Old soils on flat ground may have lost nutrients through leaching.

6 - Re-vitalisation by disturbance by ground animals (a marmot hole).

29 August 2011
© ALPECOLe 2002-2007