Biodiversity of herbaceous species in related to physiographic factors in forest ecosystems in central Zagros

The aim was to studying biodiversity of herbaceous species in related to physiographic factors (elevation, aspect and slope) in forest ecosystems of Zagros in north of Ilam, Arghavan reservoir region. For this study, 228 plots (1.5×1.5 meter) were selected based on random systematic method. In total, 88 herbaceous species belong to 71 genera and 24 families were recognized. Result showed that aspect had strong effect on richness and diversity of herbaceous species, while it hadn’t effect of evenness. Species richness and diversity were obtained higher in south aspect than north and west. Result also showed that elevation had significant effect on diversity and <1630 m elevation had high species diversity. Whereas elevation hadn’t effect on richness and evenness of herbaceous species. Furthermore slope hadn’t significant effect on diversity, richness and evenness of herbaceous species.