دانلود رایگان مقاله ظرفیت پراکندگی دانه توسط گوسفند و بز در زیستگاه مرتع خشک

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.

Conclusion

Our study showed that sheep and goats are important dispersal vectors for a broad spectrum of plant species. We conclude that endo- and epizoochorous seed dispersal is of great importance for the maintenance of biodiversity, especially for characteristic and endangered plant species in semi-natural dry grassland communities. Additionally, decisions about which large herbivores to use will influence the final outcome. Goats differ not only in fur structure, but also in food selection. Even though the main reason for grazing goats in the larger flock of sheep is to suppress the growth of shrubs and trees, they also provide numerous benefits for the local vegetation. This might also hold true for the feeding behaviour and seed dispersal properties of the old sheep breed grey horned heath especially for their influence in the maintenance of plant biodiversity