The use of Nearest Neighbor, Mean Square and Ripley's K- function methods to determine spatial pattern of Saxaul (Haloxylon ammodenderon C.A.Mey) in Siahkooh protected area, Yazd province

Saxaul (Haloxylon ammodenderon C.A.Mey) communities are important part of vegetations in central deserts of Iran. Due to their protective and conservative role specially in providing habitat for wildlife and soil erosion control, any research about them has an outstanding worth. In this research, primarily a 10 ha shrub-land of Saxaul in Siahkooh of Yazd was selected and fully callipered in 30×30 meters quadrates. In each quadrate, species, crown diameters, distance and azimuth from left downside angle were measured. Stem map of all plants was drawn by ArcMap software. Then spatial pattern of plants was determined by three

i) Nearest Neighbor, ii) Ripley’s K- function and iii) mean square method which is a kind of quadrat variance methods. Results of Nearest Neighbor method showed that, spatial pattern of plants is random. Other methods showed that spatial pattern is random, but by increasing the distance over 10 meters, the pattern tended to be clumped. Overall, the spatial pattern of Saxaul was random and tended to be clumped by increasing the distance. It seems that homogenous site conditions are the most important causes of random pattern for Saxaul species in small scale. In larger scale (far from playa), Saxaul shrubs were more dense and the spatial pattern tended to be clumped.