Diversity of plant species eaten and dispersed by the European bison Bison bonasus in Białowieża Forest

Abstract

The European bison influences vegetation by e.g. endozoochoric seed dispersal. The diet of the European bison includes 454 vascular plant species, i.e. close to 40% of the flora of Białowiez˙a Forest. Seeds contained in 75 samples of bison faeces developed into 12,392 seedlings, classified as 173 different plant species, of which 80% were perennials. Species whose seeds are disseminated via the gastrointestinal tract of the bison constitute 16% of the vascular plants recorded in Białowiez˙a Forest. The total number of plant species dispersed by bison is close to double the number recorded for domestic cattle, horses or Cervidae. The biodiversity of plant species dispersed by free-roaming bison is lower (102 species) than that of bison living in captivity (140 species). In the faeces of both free-roaming and captive bison the number of anthropogenic and meadow plant species was higher in winter than in summer. The European bison plays a significant role in the dispersal of plants, especially of non-forest species, which ensures their existence in the forest community. Plant seeds present in bison faeces which do not naturally occur in Białowiez˙a Forest (probably introduced with hay used for
supplementary feeding) contributes to the stability of flora biodiversity, but could also introduce the risk of invasion by alien species.