The most illustrative examples of vegetation zonation are found in locations where environmental conditions vary strongly at a shortdistance. Here below this phenomenon is lined out for coastal and a high mountain vegetation. Zonation, though in a less pronounced way, can be found in the district of Nijmegen along the banks of the Hatertse and Wijchense Fens.
Example 1: coastal vegetation
Zonation in the vegetation on the banks of the Hatertse Fens
Ath the Northsea coast of the the Netherlands a number of environmental factors can be named that change seen from the coast line along a perpendicular land inwards. Three factors in this profile decrease rapidly at a short distance, namely the salinity, wind velocity and mechanical influence of moving sand particles. One factor that increases is for example the formation of a stable soil. The zonation that arises shows a transition from a band without vegetation to avery open system with only a few plants adapted to extreme conditions, like Sand Couch and See Rocket, to an open grassland dominated by Marram Grass. Behind the first row of dunes the landscape changes to a more closed grassland and brushwood (low shrubs vegetation with Seabuckthorn, Sweet Briar, Dog-rose, Honey Suckle and Wild Privet). More landinward the inner dune wood can be found in which is tall trees occur, like Birch, Aspen, Oak and Sycamore.
Example 2: high mountain
At a much greater scale a vegetation zonation can be found in a mountain like for examples in the Alps. Differences in altitude can ange froma vallye at 800-1200 m high to barren rocks at 3500-4000 m high. Environmental conditions that can vary strongly depending on the altitude are:
|Vegetation zonation in mountains
|Vegetation zonation along the slopes of a mountain, from low to high altitude: deciduous tree forest, needle trees forest, (dwarf) bushes, Alm meadows, open grassland, cushion plants, mosses and lichens, Barren rocks.|
From low to high the zonation can be described as follows:
- Shortening of the vegetation season due to temperatures below the freezing point and long periods of snow coverage
- Low noctual temperatures also in summer
- High (diurnal) temperatures due to high levels of irradiation by the sun; besides a high proportion of ultraviolet light a high altitude
- Strong wind at high altitude
- More precipitation at increasing height
Deciduous forest followed by needle trees and (dwarf)bushes vegetation. Above the timber line at about 2200 m dense (close) grasslands (alm meadows) can be found and thereabove open grass land. Even higher, only sparse cushion plants grow, followed by a vegetation of mosses and lichens and finally (nearly) barren rocks.