Investigating the Pattern of Spatial Distribution of Dactylis glomerata L. and Distance-Based Quadrate Indices in Shekarab Region, Tandoureh National Park

The distribution pattern is one of the most important features of plant communities which refers to the condition and distribution of a species within a plant community. This study aims at investigating the distribution pattern of Orchard grass (Dactylis glomerata) assuming that the density of the plant is procedural. The study area was located in Northern Khorasan province, 30 km from the south of Dargaz. A systematic random sampling method was used to collect samples from three Northward ranges. Each domain was divided into three sub-domains, including high density, medium density, and low density (from high to low range). In each sub-domain, the random sampling was carried out from five plots (2×1) and one 30-meter transect which contained 10 randomly selected spots. A total of 45 plots and 9 transects were used to sample the region. Indices used in this study included Johnson-Zimmer distance index and the quadrate indices of Eberhart and the standard Morisita. The experiment carried out in Shekarab region of Tandoureh National Park revealed that this plant has a clumped distribution pattern based on Johnson-Zimmer and Eberhart indices. Morisita indices and standard Morisita showed different distribution patterns.