Study of spatial pattern of Plants using point pattern analysis, spatial and quadrate indices (Rangeland of Fereidan in Isfahan province)

Spatial patterns of vegetation in a range type dominated by Bromus tomentellus and Astragalus verus in Feridan- Isfahan were studied. Four 50 m2 reference sites were randomly selected (5 by 10 m). All perennial species were counted and their coordination were recorded accordingly. Two approaches were used to measure average distance between plants including “Closest individual” and “Nearest-neighbor method”. Individual plants were counted in quadrates. Spatial patterns of vegetations were determined using three methods including, Point Pattern Analysis, Spatial Indices (Hopkines, Pielou, Johnson and Zimer Index) and Quadrate Indices (Green and Morisita Index). Results indicated that perennial species had randomized spatial patterns due to the relatively homogeneous environmental characteristics of studied area and also selective pattern of vegetation. Point pattern analysis had more accuracy because it considered all perennial species coordination. With sufficient sample size and appropriate quadrate size and shape, quadrate indices had acceptable accuracy. Hopkines index had more precision to determine spatial pattern of vegetation than Johnson, Zimer and Pielou indices. It indicated that spatial indices based on the plant to plant distance (Nearestneighbor method) had more precision than indices that derived from point to plant distance (Closest individual).