Reintroduced species as vectors for seed-dispersal

Reintroductions may play an important role in re-establishing key ecosystem functions. We focused on the role of reintroduced ungulates as internal seed dispersers (endozoochory). We compared seed dispersal by three plain ungulates inhabiting the Negev desert in Israel: the reintroduced Arabian oryx (Oryx leucoryx), a medium sized bulk feeder ruminant; the reintroduced Asiatic wild ass (Equus hemionus), a large hindgut fermenter; and the extant ungulate of the region, the Dorcas gazelle (Gazella dorcas), a small concentrate selector ruminant. We collected 5–10% of the mass of clearly delineated fresh dung piles, and germinated them in sterile soil. We found that each species dispersed a unique plant community with little overlap. The wild ass transported the most species, followed by the oryx, and lastly the gazelle. In addition, the area’s keystone plant species, Acacia raddiana and Acacia tortilis, were overwhelmingly transported by the two reintroduced ungulates, especially the oryx. The passage through the oryx digestive system was found beneficiary not only for the Acacia seeds’ germination success but also for the initial growth rate of the Acacia seedlings. Reintroduced large ungulates facilitate the restoration of key ecosystem functions and contribute to restoring biodiversity well beyond the preservation of the reintroduced species itself.