Effects of altitude gradient and physical and chemical soil factors on functional and distribution characteristics of Ferula haussknechtii H. Wolhff ex Rech. f. (Case study: Bayenchob Rangelands, Saral of Kurdistan)

This research was conducted to evaluate the environmental factors affecting functional characteristics (biomass, density, regeneration, cover%, basal area and species richness) of Ferula haussknechtii in Saral rangelands of Kurdistan. After determining three altitude classes (1850, 2250 and 2650 m), a systematic-random sampling was performed to measure aboveground biomass, cover percentage, height, basal area, and density of Ferula haussknechtii with 1.5-m2 plots along transects. In each plot, a soil sample was taken from 0-30 cm soil depth. Soil texture, CaCo3, acidity, electrical conductivity, nitrogen, potassium, phosphorus, and sodium were measured in the laboratory. Analysis of variance of data was done using a randomized complete design with R software, and also CCA was used to compare the relationship between species and environmental factors. The results showed that aboveground biomass, vegetation percentage, height and density of Ferula haussknechtii increased with increasing altitude, while the basal area of this species decreased. The green biomass, cover percentage, basal area and height of this species were positively correlated with nitrogen, carbon, potassium, silt and clay and negatively correlated with acidity, phosphorus and sand. The results also showed that due to the impact of this valuable species on the soil stabilization, forage supply and production of active ingredients, altitude, nitrogen, carbon, clay and silt were the most effective factors in establishing this species.