Climate
There are many different climatic factors – wind, humidity, air and soil temperature – which, together with soil conditions, distribute the plants to grow in different places in the landscape.
A parched sunburnt sandy wind-swept slope without a hint of topsoil is a harsh place for a little seed to take root. Only the hardiest manage to do it. Grey hairgrass is one of the hardy ones. Thyme and crowberry can also be lucky and gain a foothold. Sand sedge migrates in via root shoots. Reindeer moss also finds a foothold here and there and spreads.
A short distance further to the south, where the thicket has grown higher and has provided shelter against the often strong westerly wind, the plants have established a more ground-covering and diverse community than on the windy slope with grey hairgrass – with a number of other species. Gradually, as the low thicket grows higher and the hardy grey hairgrass, among others, multiplies, it covers the white sand, improves conditions for growth at the site, and neighbouring plants then move in. This process often goes under the lofty name “succession”, which suggests inheritance. The last arrivals have indeed also inherited the site in a way after the hairgrass.
Succession can be seen in many other places where the plant growth is able to develop over a number of years.