فهرست مطالب خبات امامقلی

The aim of this study was to evaluate the most important environmental factor affecting changes species diversity in rangelands of Bijar protected region. Sampling in each plant type that was determined from field method was done along four 300 meter transects. 15 plots (1m2) established along each transect in 20 meter distances. The kind and the amount of existing species and the percentage of vegetation cover were determined in each plot. Also were taken soil samples from beginning and end of each transect from 0-20 and 20-100 cm depth. Measurement environmental factors in this study were included: soil texture (clay, silt, sand), gravel percentage, slope, aspect, altitude, organic material, EC, pH and lime. Species diversity in each type with counting total species as species richness were considered. Simpson and Shanon-Winer index as heterogeneous index and also Simpson, Kamargo and Smith-Wilson indices were considered as homogenous indices. Above mentioned case calculated using from Ecological Methodology. After collecting data, the Principal Component Analysis (PCA) was used to determine environmental factors affecting on changes of species diversity. The results showed that Ac. millefolium-S.barbata and D.mucronata-Th.kotschyanus types have the highest and lowest species diversity respectively. The obtained results of this study was showed that among studied factors, texture include clay, silt and sand percentage gravel, lime; altitude and slope had the most influence on changes of species diversity in studied region.Results from this study can be used to manage, restore and improve vegetation in areas with similar environmental conditions.