Effects of topography and soil on vegetation in Zavareh rangelands, Ardestan - Isfahan province

By studying relationships between topography, soil and plant characteristics, there is more chance to achieve appropriate management based on ecological principals. This study aimed to evaluate the role of topography and soil characteristics in vegetation, and identify the most critical factors affecting the vegetation distribution. The study area is located in Ardestanrangelands, Isfahan province, Iran. Slope, aspect, elevation and geology maps were integrated using ArcGis software version 9.2, and fourteen homogeneous units were produced. These unites were decreased to nine as no significant changes were detected between them. Vegetation and soil characteristics were studied in these unites. In each unite, two belt transects with each 300 meters in length were established and vegetation characteristics were sampled in plots with 20 meters distance from each other placed along the transects.. Vegetation flora was also studied. Soil samples were collected from various parts of transects (at the beginning, middle and end) and their chemical and physical properties were analyzed. Principal Component Analysis (PCA) was used to interpret the collected environmental and vegetation data. According to the results, the two first axes of PCA explained 78.38 percent of variance of the vegetation distribution in the studied unites. Soil texture, electrical conductivity, Caco3, Caso4, Ca and organic matter content were the most important factors controlling the distribution of vegetation in the area.