Potential of seed dispersal of rangeland species by Gazelle subguttrosa in arid and semi-arid ecosystems

In order to assess the potential seed dispersal of plant species by herbivores in rangeland of arid and semiarid ecosystems, Gazelle subguttrosa in Kolah-Ghazi National Park was selected. In this experiment, five main habitats with five replications were studies. During spring and autumn in growing seasons 10 freshly pellet groups of herbivore were randomly collected in each of selected habitat and totally 250 dung sample. Seed contents of dung samples were determined in greenhouse germination experiments were performed over 8 months. In total, 833 seedlings from 60 plants (43 seed species in dung samples of gazelle), mainly annual with attractive inflorescence and small seeds which only colonize through endozoochory were recorded in. The highest and lowest seed densities were recorded in April and October. Given the composition, density and species contents, seed contents variations in dung samples were evaluated via multivariate analysis DCA. Seed contents in dung samples varied significantly. Overall, seed contents of dung samples varied in different months so that dung samples collected in the first three months:April, May, and June were located on the left side of the first axis of DCA while those in other months in right side of first axis respectively. Analysis of variance coordinates of dung samples in different months showed significant differences in the seed contents (P=0.02). The seed contents of dung samples in April and May were significantly different from other three months, but this difference was more pronounced in the autumn months.