Investigation of Relationship between Vegetation, Topography and Some Soil Physico-Chemical Characteristics in Nodoushan Rangelands of Yazd Province (Iran)

The relationship between topography, soil factors, and distribution of ecological vegetation groups in the Nodoushan arid rangelands of Yazd province (Iran) was investigated. The present species were recorded in each vegetation group using a randomized-systematic sampling method. Plant cover and density were estimated quantitatively using the transect and quadrate methods, and the two-way indicator species analysis (TWINSPAN), after which vegetation was classified into different groups. Soil samples were taken from 0–30 cm in each quadrat. In each vegetation group, 20 environmental variables including altitude, slope, aspect, percentage of bare rock, grazing intensity, percentage of gravel, soluble ions (Na+, K+, Mg2+, Ca2+), total nitrogen, organic matter, lime, gypsum, EC, pH, and percentage of sand, silt and clay were measured. Multivariate techniques including detrended correspondence analysis (DCA) were used to analyze the collected data. The results showed that the vegetation distribution was related to elevation, slope, and soil characteristics such as texture, organic matter, gypsum, acidity, lime, and gravity percentage.