Habitat assessment for Vaccinium arctostaphyllus L. by logistic regression method in the rangelands of Namin-Ardabil

To assess the potential habitat of plants and appropriate planning for conservation and restoration policies the best fitted method should be used. In order to model the habitat distribution of the rare species of Vaccinium arctostaphyllus L., within the eight habitats of the plant, two place, with and without the species, were selected. Random-systematic method in the growing season was used. Data on different factors such as latitude and longitude, physiography of each habitat were recorded using GPS at 40 point. Soil samples were collected from a depth of 0-30 cm (active rooting depth). Then some physical and chemical properties of soil such as pH, electrical conductivity, soil texture, lime, soluble potassium, magnesium, soluble sodium, particulate organic matter, absorbable phosphorus, soluble bicarbonate and percentage of clay, silt and sand were measured in the laboratory. In the next step, logistic regression was used to determine the relationship between environmental factors and the distribution of V. arctostaphyllus L. Map of environmental factors affecting the distribution of the species was prepared using IDW spatial statistics to evaluate the interpolation methods. The Kappa index was used to assess the matching of forecasted map and the ground truth. The results of logistic regression showed that the most important factors affecting the distribution of V. arctostaphyllus L. were slope, geographical direction, phosphorus and silt. Presence of the species negatively is related to the geographical direction. Overlapping of the areas showed that these species are distributed in high slope and west and southwest direction. Also, the compliance of the forecast map with the actual habitat map was assessed at a good level (Kappa index: 0.65). In general, the results showed that the logistic regression method is able to give a good prediction for the habitat of the V. arctostaphyllus L. species. The results of this study could be used to identify and evaluate the susceptible habitats of this species and the possibility of conservation, reproduction and breeding as a rare and native medicinal plant.