Evaluating various indices for determining the spatial patterns of Artemisia fragrant and Bromus tomentellus (Case study: Baladeh Rangelands, Mazandaran)

This research was carried out to study the distribution pattern of Artemisia fragrant and Bromus tomentellus in Razan-Khushvash mountainous rangelands located around Noor city. Random- systematic approach was used to collect the data along three 100 meters transects within the 2200 and 2400 elevation range. Ten random points along each transect with distance of 10 m were selected and the data were collected from 30 points. The distance of to the nearest plant to the selected random points, that plant to nearest neighbor plant and distance of random point to second nearest plant were measured. One square meter plots were placed at the random points and the numbers of plant individuals were also counted. The plant distribution indices (Eberhart, Hopkins, Holgate, Johnson and Zimmer) were then calculated. The quadratic indices of species dispersal (Variance mean, Green, Lloyd, Morisita and Standard Morisita) were also calculated. One hundred percent inventories as control were conducted in 100m2 and 200m2 plots for Bromus tomentellus and Artemisia fragrant respectively. According to the calculated indices (Eberhart, variance mean, green, Morisita and standard Morisita), Artemisia fragrant had clumped pattern in the study area. Bromus tomentellus had a random to clumped pattern based on some calculated quadrate indices as it was confirmed by the one hundred percent inventory. Although the obtained results from Variance mean, Green, Morisita and standard Morisita indices showed a clumped pattern for Bromus tomentellus, Hopkins index showed a random pattern for the species. Overall, quadratic indices can be recommended to study the spatial pattern of the species in the study area compared to distance methods.