Hassan Pourbabaei, Mehdi Heydari and Ali Najafifar
Abstract
The study was carried out in a part of Ghalarang protected area located in northwestern Ilam, featuring central Zagros forest ecosystems. The objective was to investigate the relationship between plant diversity and some physiographic attributes. The field data were collected using a number of 50 plots in a systematic randomized sampling. The factors including tree and shrub species type, number, and canopy coverage were recorded by measuring their small/large diameters in each plot. In order to record the grass species, the Whitakers nested plot method was applied. The results showed that there are 4 tree species, 3 shrubs, one bush species and 78 grasses in the study site. The family Asteraceae and the genus Euphorbia sp. form the most existing plants. Therophytes cover the most vegetative forms in the area. Plant diversity was the most in southern and southwestern and the lowest in western aspect. Moreover, plant richness was the most in southern and southwestern aspects. There was the most plant diversity and richness in the intermediate altitudes, while the high altitudes had the least diversity. The slope percentage had not a significant difference on plant diversity, richness and evenness.