Effects of Wild Boar (Sus scrofaL.) Rooting on Seedling Emergence in Białowieża Forest

Abstract

The wild boar is an omnivorous animal, and by foraging (rooting) disturbs the top soil layer. In some regions of Poland and Europe seasonal fluctuations in rooting have been observed. Wild boars not only eat plants, but also strongly modify their habitat. In Bialowieza National Park wild boar most frequently visit oak-hornbeam forests on fertile soil. On sites where the forest floor is covered with dense vegetation the germination of seeds is difficult, and wild boar rooting can promote the removal of diaspores from deeper layers of the soil seed bank. Within a 3-year observation on 30 subplots about 10,000 seedlings emerged representing 38 species. Our study revealed that rooted patches are characterised by a very rich and diverse flora of seedlings representing mostly forest species, but their density is low. The dominant species germinating in the disturbed ground vegetation is Urtica dioica, a species forming the persistent soil seed bank. There is a possibility that seedlings of herbaceous plants emerging on permanently rooted patches are of exogenous origin, since the seeds germinating there were in many cases damaged by repeatedly rooting animals and had no chance for further growth and reaching the generative phase. However, the soil seed bank in the rooted area has to be analysed to confirm this theory, that they have exogenous or endogenous origin. Seedling density in a repeatedly rooted oak-hornbeam forest is determined by factors other than those related to rooting. In this context the present study did not demonstrate a negative impact of rooting intensity on seedling emergence.