Above the tree line, conditions are so incredibly hostile that trees can no longer win the battle with the elements. Yet, every year many species of alpine plants flourish and alpine meadows turn into colorful flower displays. How do alpine plants survive in this extreme habitat? Adaptions, of course!
UV radiation, drought & other misery
Plants that occur in alpine terrain – roughly above 2000 meters – are, after all, faced with severe temperature fluctuations, with warm summer days alternating with cold freezing nights. Moreover, the weather can suddenly change, think of storm, wind, hail, heavy showers and in the middle of summer it can suddenly snow. There is also no shade to protect against the merciless sun, so the strong ultraviolet rays can cause burns on leaves. Sometimes alpine plants like saxifrages or moss champions just grow on bare rock, almost without soil. And then there is drought! Mountain air contains less water vapor and is therefore drier than “low air”. The wind – which is often strongly present – dries out the environment even further. This creates a dry environment, despite the fact that precipitation regularly falls out of the sky in huge amounts.
Flora adaptations and smart tricks
Fortunately, every plant species above the tree line has its own strategy to cope with the extreme circumstances in which it lives. For example:
Edelweiss (Leontopodium alpinum) – the symbol of the Alps – is covered with a layer of white downy hairs to prevent evaporation of precious moisture. In addition, the down protects the plant against ultraviolet radiation. Cobweb houseleek (Sempervivum arachnoideum) uses the same trick and covers itself with – as its name suggests – cobweb-like hair.
- Besides, houseleek is a succulent plant and – just like its family members in the desert – it can store water and nutrients in its thick, fleshy leaves. This is a trick that several species above the tree line use, including saxifrages. Another example of alpine succulents is the Alpine rock-jasmine (Androsace alpina).
- Staying small is another way to protect yourself from dehydration. Small leaves help prevent evaporation of precious moisture and staying low to the ground – preferably behind a rock or in a dimple – works as a protection against the harmful effects of the wind. The moss campion (Silene acaulis) is therefore usually found in crevasses, between rock debris or on stony alpine meadows.
In short: all alpine plants and flora have brilliant adaptations to the conditions at high altitudes!