Evaluation on the effect of de-icing salt along snowy road on vegetation composition and diversity (Case Study: mountain road of Godar Kafanooieh of Baft as the roof of Iranian desert)

An intense utilization of salt as lowering the freezing point of water in the mountainous areas of Iran country has been applied for long period. Therefore, this study aimed to determine the effect of road deicing salt on the vegetation composition, species richness and diversity indices in rangeland ecosystems of the area adjacent of Godar Kafanooieh road, Baft-Kerman, Iran in 2016. Sampling of vegetation was carried out after determining a homogeneous area of ​​ecological factors on the side of the road where runoff flowed into it. The establishment of 80 plots on a systematic sampling of vegetation along the four transects with length of 150 meters were taken.In this regard, the first ten plots on each transect were established every 5 meters and the distances between other plots were 10 meters. After calculating the diversity and richness indices based on presence or absence of species in the PAST and BIO-DAP softwares, the effect of distance from the salting road was performed by one-way ANOVA test and mean comparison was analyzed by Duncan's multiple range test. Results from 0 to 40 meters far from the road showed that plant species as Hertia intermedia, Ephorbia larica and Glycyrrhiza glabra have allocated high proportion of species composition. A significant increasing rate of Dominance and Burger indicators (86.7 and 97.7 percent in comparison to near road and 18.27 and 115 percent in comparison to furthest away distance from road (150 meters), respectively) and decreasing of Simpson, Shannon, Margarof, Menhing and Fisher indicators(45.2, 49.6, 38.5, 14.6 and 30.2 percent in comparison to near road and 53.4, 68.5, 77.6, 51.4 and 76.8 percent in comparison to the furthest away distance from road (150 meters), respectively) at the 40 meters far from the road indicated the dominance of few species with high population (mostly Salsola inconesense). Native rangeland species (Artemisia aucheri) along with other species such as Stipa barbata and Astragalus parrowianus were observed at 50 meters distance from the road and their contribution in vegetation composition were raised with increasing the distance. According to this research, salt deicing due to changing the ecologic condition for invader and halophyte species, will decrease richness and diversity species and lead to diminishing potential associated to increasing vulnerability of near rangeland ecosystems.