Ecological parameters affecting the distribution of Vaccinium arctostaphylos L. in ecotone rangelands of Namin County, Iran

The aim of this study was to investigate the ecological factors affecting the distribution of the rare, endangered and medicinal species of Vaccinium arctostaphylos L. in ecotone rangelands of Namin County in 2019.

Sampling were performed from the presence and absence locations of V. arctostaphylos in eight habitats. Soil samples were taken from a depth of 0-30 cm and physiographic variables in were recorded. Moreover, a digital elevation model, slope and aspect map was derived. Rainfall and temperature gradient maps, was derived using gradient equations, and the values for sampling points were extracted. Data analysis performed by independent t-test and discriminant analysis test.

Results showed the Stream Power Index (SPI) (p<0.05), pH, EC, lime, soluble sodium, organic carbon, soil texture and species density (p<0.01) are significantly different between the presence and absence of the species. Results of discriminant analysis showed the three functions explained 86.4, 10.7, and 2.8% of the total data variance, respectively. Generally, 19 variable including elevation, slope, aspect, precipitation, Topographic Wetness Index (TWI), plan curvature index (PC), SPI, pH, EC, lime, phosphorus, soluble potassium, soluble sodium, magnesium, organic carbon, bicarbonate solution, saturation percentage (SP), sand percentage and species density were identified as the important factors affecting the distribution of V. arctostaphylos. SP was the most important factor in the presence and absence of species.

Generally, by identifying the most effective ecological factors on the distribution of V. arctostaphylos, effective steps have been taken to improve the habitat of the rare species.