European bison are ruminants that eat grasses and herbs as well as buds, leaves, twigs and bark. During late Summer and Autumn they also forage upon acorns, beech nuts and berries. They bend branches and trunks to reach nutritious parts. Bison debark more than any other large herbivore in Europe, which enables them to keep full-grown forests and shrubberies open. When a tree is blown down during a storm bison will soon discover it, stripping off its leaves, buds, twigs and bark. Bison sometimes also scrape away soil in order to reach the roots of grasses, trees and shrubs.
In Kraansvlak, the bulk of the diet of bison consists of grasses, besides bark (a.o. Spindle tree, Maple tree) and acorns. Therefore the animals need open woodlands and shrubberies to obtain a sufficient amount of food. They partly contribute to this themselves: closed Sea buckthorn shrubs are opened up to get to delicious snacks. In close Spindle tree shrubberies first all shrubs are debarked. After a few years, most Spindle trees disappeared being replaced by grassland and new young bushes. In combination with konik horses and fallow deer, a semi-open shrub system appears. Grasses initially grow explosively under the deteriorating shrubberies. The bison eat the nutritious grasses to a medium length, after which the horses graze off the rest locally. This enables flowers, but also trees and shrubs a chance to germinate. The young trees and bushes are suppressed by roe deer, fallow deer and bison. The result is a varied landscape with short grassy flower rich areas, rough grasslands, young shrubberies and solitary shrubs and trees.
This video shows some great examples of the foraging behaviour of bison in the Polish Bialowieza forest.
Different grazing behavior
Bison, cattle, horses and smaller herbivores such as roe deer, fallow deer and rabbits all show their own behavior. Horses graze of grasses shortly and also require dry grass for proper digestion. Cattle moreover feed upon lush grasses in addition to twigs. Bison graze less than the other two species and eat leaves and young shoots as well as debark more trees and shrubs. Roe deer and fallow deer nibble from shrubs, and rabbits forage upon short grasses. Together, all grazing animals assure a varied dune landscape is in place in which trees, shrubberies and grasslands are abundant. Bulls make so-called rutting pits and by doing so help dune dynamics. Bison often take sand baths in the area, this is beneficial to many pioneer plant species. The paths wild animals use, connect resting spots, sand baths and rutting pits with each other and form a highway for sand beetles and other species present in open dune landscapes.