TY - JOUR T1 - Evaluating the Effects of Study Scale on Spatial Patterns of three Range Plant Species Using Quadrate Indices and Point Pattern Analysis in Chaharmahal- Bakhtirai Province Rangelands TT - بررسی اثر تغییر مقیاس بر الگوی پراکنش مکانی سه گونۀ مرتعی با شاخص‌های فاصله‌ای و روش آنالیز نقطه‌ای در مراتع استان چهارمحال بختیاری JF - IJAE JO - IJAE VL - 5 IS - 17 UR - http://ijae.iut.ac.ir/article-1-788-en.html Y1 - 2016 SP - 37 EP - 49 KW - Distance based index KW - Point pattern analysis KW - Rangeland ecosystems KW - Shahr-e-Kord. KW - Spatial pattern. N2 - This study aimed to investigate the spatial patterns of Acanthophyllum microcephalum Boiss, Nepeta glomerulosa Boiss and Hertia angustifolia and evaluate the effects of study scale on spatial patterns of three range plant species in Ghale-Gharak research-station located in Shahr-e-Kord. 40 points with a distance of five meters from each other were selected for sampling of vegetation along four 50 m transects using a random-systematic approach. The species spatial patterns were measured by 6 different distance-based methods including Hopkines, Johnson-and-Zimer, Eberhardt, Holgate, Hines and T-Square-index. A 100 m2 reference site (10 by 10 m) was selected to record the species co-ordinates and conduct point pattern analysis. The spatial patterns of the species were determined in 3 scales of 10×10, 5×10 and 5×5 meters to highlight the effects of scale on spatial patterns of vegetation. According to the results, H. angustifolia showed randomized spatial patterns due to its seed dispersal ability. N. glomerulosa and A. microcephalum showed a clustered spatial pattern beacuse their seed are in achene form and fall next to these species. All the 3 species had a clustered pattern when the scale of point pattern analysis was decreased. Identifying these plant spatial patterns and their controlling factors) such as seed dispersal mechanisms of the species and sampling scale) are required to select the best sampling strategy in rangeland assessment programs. M3 10.18869/acadpub.ijae.5.17.37 ER -