Effect of Drill-Seeding by Prangos ferulacea on vegetation composition in rangeland ecosystems of central Zagros

Drill-seeding with  Prangos ferulacea had been a common technique of rangeland restoration in central Zagros. It seems that no sufficient attention has been paid to ecological fitness of this species at planting time. Also, no monitoring has been done to show this species impacts on composition species after drill-seeding. In this study the effect of drill-seeding of this species was studied on species composition. This was carried out on Tange Sayad rangelands in Chaharmahal and Bakhtiari province. Vegetation was sampled on four sites, one as control and three densities of drill-seeding with P. ferulacea (low, moderate and high). The sampling was done using 2.25 m2 plot along transects. The result of this study showed 75 species were recorded in this area. In control site and low, moderate and high density of drill-seeding by Prangos 69, 50, 30 and 33 plant species respectively. The results showed that the species Astragalus microcephalus, Bromus danthoniae, Bromus tectorum and Melica persica were  the major species in control site and Geranium tuberosum, Prangos ferulacea and Ziziphora tenuir were higher tended to high density of Prangos. Also, Multivariate analyses showed that drill-seeding significantly influenced the species composition of vegetation composition. The result showed that goal of restoration was achieved regarding forage biomass and soil conservation. However, this species have negative impact on vegetation due to its dense stand. Therefore, it is recommended to avoid dense seeding. Also, it is better to apply mixed seeding.