The most important factors affecting the distribution of wild almond (Prunus scoparia (Spach) C.K.Schneid.) in Razavi and South Khorasan provinces, Iran

Background and objectives: The presence of plant species in each region is influenced by the environmental and biological factors of that region. Therefore, to establish the coverage and distribution of plant species and the factors affecting their growth and development, it is necessary to research the ecological requirements of the species and the environmental characteristics of the studied area. This information can be used for planning and implementing basic management plans for the restoration and modification of habitats and the protection of water and soil resources. This research aims to identify the habitat conditions of Prunus scoparia (Spach) C.K.Schneid.
Methodology: This research was conducted in Razavi and South Khorasan provinces across six habitats: Qaen, Bajestan, Ferdows, Khaf, Bardaskan, and Sarayan. In each representative area, a site was selected, and three transects of 100 meters were established, each with a distance of 20 meters. Along each transect, 10 plots of four square meters were established (a total of 30 plots in each habitat). In each plot, the percentage of canopy cover, density of a single plant species, litter percentage, and bare soil percentage with pebbles were determined. Additionally, for each habitat, two soil samples were collected from the beginning and end of each transect, resulting in a total of 36 soil samples. The soil texture, electrical conductivity, saturation moisture, pH, total nitrogen, phosphorus, potassium, sodium, calcium, magnesium, chlorine, lime, organic carbon, and organic matter were analyzed using conventional methods. After collecting all the climate, soil, topography, and vegetation data related to the six habitats of wild almond in Khorasan province, the scope of the ecological expansion of the studied species based on the studied factors was first determined. Then, using principal component analysis (PCA), the environmental factors affecting the distribution of wild almond species were identified.Results: The results showed that the Ferdows habitat exhibited the highest percentage of vegetation cover, while Bardaskan had the highest canopy cover percentage, density, and mean height for wild almond. The lowest percentage of vegetation cover, canopy cover, and density of the species was found in Bajestan, and the lowest mean height of the species was recorded in Khaf. Soil physical properties, such as soil texture components including the percentage of clay, sand, slope, and calcium, showed the largest contribution to explaining the variance of axis 1 and are more important than soil chemical properties. In the Bardaskan habitat, calcium and slope had a positive effect on the distribution of wild almond, but the percentage of clay showed a negative effect. Organic carbon is effective in the species distribution in this habitat. Altitude and rainfall are effective in the distribution of wild almond in Qaen. In general, clay, calcium, slope, sand, and maximum temperature play the biggest role in the distribution of the species in all the studied areas. There are many variations in the soil properties of the habitats. The two habitats of Khaf and Bardaskan are similar to each other in terms of soil characteristics, and wild almond is distributed in these habitats with high slopes and a high percentage of sand and calcium. In general, considering all the climatic, soil, and altitude characteristics, wild almond habitats are placed in three clusters. Khaf and Bardaskan habitats were in the first group, Sarayan and Bajestan habitats were in the second group, and Qaen and Ferdows habitats were in the third group.Conclusion: The range of distribution of wild almond in the studied areas was around 1480 to 1700 meters above sea level, generally in southern directions, with slopes ranging from 10% to 66%, and annual rainfall between 130 to 187 mm. The soil texture of the habitats is loamy to sandy-loam, and the soil is non-saline. Among the studied factors, soil calcium, soil texture, slope percentage, and maximum temperature had the most significant effects on the distribution of wild almond in the studied areas. Considering the distribution of this plant in a wide range of environmental conditions, including climate, physiography, and soil, and its positive effect on controlling soil erosion on slopes, it is recommended to cultivate this species in degraded mountainous areas.