Endozoochorous seed dispersal by large mammals is one of the most important mechanisms affecting long-distance dispersal of plant species. Herbivores functional groups play different roles in endozoochorous seed dispersal. The aim of this study was to investigate the potential of endozoochorous seed dispersal by the two herbivores, the red and the roe deer, and two omnivores, the wild boar and the brown bear in the Golestan National Park. To investigate their potential endozoochorous seed dispersal, two different seed germination methods were used: controlled greenhouse and natural conditions. After dung samples preparation, two 20-g paired sub-samples were extracted from each of the 445 faecal samples and assigned to each of the two methods. The plants germinating from the faecal samples of the animal vectors feeding in the same habitat and season were compared to investigate the contribution of each species to the composition of the dispersed pool in two different habitats (forest, and prairie-forest ecotone).The results were then compared with the species composition of the above-ground vegetation and soil seed bank in which the dung were collected. Totally, 136 plant taxa (3078 seedlings) germinated from the 445 paired dung sub-samples. We observed remarkably higher taxonomic richness and abundance under controlled greenhouse than under natural conditions (p ? 0.001). Graminoids and forbs composed 91% of the seedlings in greenhouse but shrubs were more abundant (55% of the seedlings) under natural conditions. Based on the species accumulation curve, red deer followed by wild boar dispersed a substantially higher number of plant species compared with other mammals under greenhouse condition, while under natural conditions brown bear was the most effective vector. In general, seed density in the dung sub-samples depended on the feeding regime of the vectors and followed a seasonal pattern compatible with plant seed shedding periods. The studied herbivores were more effective vectors than the omnivores in spring, when herbaceous plants dominate. Whereas, shrubs were mostly occurred in omnivorous dung samples collected in summer and autumn. The richness and abundance of the germinated plant species differed significantly between those emerged from dung and soil seed bank (p 0.05) except for brown bear. However, the Canonical Correspondence Analysis (CCA) confirmed differences between brown bear dung seed content and soil seed bank (F 483, 8 =3.367, P 0.001), which was related to high number of shrub species in brown bear dung sample. With regard to omnivore species, there was high correlations between local flora and dispersed flora (P 0.05, r s = 0.69), and soil seed bank and dispersed flora (P 0.01, r s = 0.83) in forest habitat type. While, there were high correlations between soil seed bank and dispersed flora by herbivores in both habitat types (P 0.01). These results allow the conclusion that: (1) The four studied sympatric vectors provide different seed dispersal services and may therefore, be regarded as complementary; (2) A positive bias occurs when only considering germination under controlled greenhouse conditio and (3) Animal vectors can affect both the above-ground vegetation and soil seed bank in local and regional scales. Therefore, management plans for sympatric herbivore populations should take account of their varying seed dispersal functions. Keywords : Endozoochory, Herbivores, Local flora, Omnivores, Potential endozoochorous seed dispersal, Soil seed bank