The role of brown bear (Ursus arctos) in the plant seed dispersal of Golestan National Park
Tarkesh Esfahani, M.
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The brown bear (Ursus arctos) is the largest carnivore species in Iran. It can be found in large parts of the Alborz and Zagros mountain ranges, but remarkable densities occur in the northern forest, ranging from Golestan National Park to the western Gilan. We investigated the potential of brown bear for endozoochory in Golestan National Park through a greenhouse experiment. In order to detect the temporal and spatial variability of the emerged seedlings, abundance, species richness and composition of the germinated seeds from the faecal samples collected in different habitats and across seasons were analyzed. A total of 268 seedlings belonging to 33 plant taxa, 25 genera and 19 families germinated from 64 brown bear faecal samples. Based on the obtained results, we could show seasonal variability in the number (P=0.003) and composition (P=0.001) of the dispersed seeds, which could be attributed to the plant species phenology. There were no significant differences regarding seed abundance and composition between the two types of habitats. Similarly, seed species richness did not significantly differ across seasons and habitats. Herbaceous growth form (24 taxa) represented the highest species richness in the germinated plants, while shrub plants were the most abundant germinated species (76% of the total germinated seeds). Fleshy fruits were the principal source of energy during the hyperphagia phase prior to hibernation. In contrast, seeds from dry fruits were observed in lower densities in the faeces, especially during spring and early summer. This was in line with the opportunistic feeding behavior of the brown bear. Considering that co-occurring ungulates in Golestan National Park are rather dispersed annual species, we could highlight the role of the brown bear in specifically dispersing shrub and tree species.
- RESEARCH: CIB Associates