Open Access

Kiowa Alraune Schulze, Rainer Buchwald, Thilo Heinken

• Large herbivores are significant vectors for the long distance dispersal of seeds in various habitats, both attached to animals (epizoochory) and via gut passage (endozoochory). The majority of studies on epizoochory have examined dispersal in the fur of domesticated ungulates. Studies on wild ungulates are important to understand dispersal processes in many habitats, but rare due to methodological constraints. We studied epizoochory of seeds by European bison in an open-forest-mosaic (nutrient poor grassland and heathland, mixed forest) in NW Germany, where bison had been introduced for the purpose of nature conservation. At the study site it was possible to apply a method by which hoof material of freeranging bison was non-invasively collected. We identified a total of 1082 seeds from 32 plant species in the hoof material. The three most abundant species were Polygonum aviculare, Agrostis capillaris and Betula spp. Seed species originated from various habitat types of the study area, while the majority of seeds derived from trampled areas. Compared to the non-dispersed plant species of the study area, dispersed plant species had a higher seed longevity index, suggesting that many seeds were picked up from the soil seed bank. Epizoochory ranking indices of dispersed seed species, classifying the importance of epizoochory, revealed that transport in the fur may be of minor importance for many species, i.e. epizoochory by the hooves turned out to be negatively correlated to epizoochory in the fur. We conclude that European bison disperses a considerable number of seed species through trampling. Further research should consider epizoochory via the hooves and include integrative approaches to understand the different dispersal mechanisms by ungulates and their longterm synergetic effect on plant communities.
• Die Ausbreitung von Diasporen ist ein essentieller ökologischer Prozess zur Erhaltung der Phytodiversität in einer Landschaft. Es ist bekannt, dass Großherbivoren in ihrem Habitat als passive (epizoochor, externe Samenanheftung) und aktive (endozoochor, Nahrungsaufnahme) Ausbreitungsvektoren über große Distanzen wirken. Die Mehrzahl der relevanten Untersuchungen (u. a. Fischer et al. 1996, Couvreur et al. 2004, Cosyns et al. 2005) wurde mit domestizierten Huftieren durchgeführt. Dagegen ist weniger bekannt über die Rolle wildlebender Huftiere als Ausbreitungsvektoren, weil derartige Studien überwiegend an geschossenen oder anderweitig immobilisierten Huftieren durchgeführt worden sind.