Seed dispersal capacity of sheep and goats in a near-coastal dry grassland habitat

Abstract

Our aim was to investigate the influence of seed dispersal via sheep and goats on the biodiversity of the characteristic plant community and endangered plant species in near-coastal dry grasslands. We examined epi- and endozoochory by sheep and goats, grazing with a shepherd in a protected dry grassland area in northern Germany. We recorded the species and density of seeds trapped in fur and excreted in faeces of sheep and goats. These two ungulates dispersed seeds of 44% of all the species from the study site. These included seeds from 31 locally endangered plant species. The diversity and number of seeds were higher in fur and faeces of sheep compared to goats. This pattern was also found for the occurrence of seeds from plants characteristic to this habitat and Red List species. Extrapolation of these observations to the whole flock of sheep (n=630) and goats (n=20) suggests that there are about 357,000 seed transported in the fur whereas up to 1,500,000 seeds are dispersed via endozoochory. These observations underline the importance of free-ranging sheep and goats in shaping the biodiversity of plant species in dry grasslands.