The effects of soil properties and physiographic factors on plant communities distribution (Case study: Behrestagh Rangeland, Haraz)

The main goal of all ecologists is to preserve the ecosystems stability، this will not achieved unless with preservation of biodiversity. Plant communities، as primary producers، are perseveres of biodiversity in natural habitats. In conclusion for ecosystem management and biodiversity assessment in large scale، it is essential to study plant communities distribution. Current study was done in mountainous rangeland of Behrestagh of Amol in Mazandaran province. Vegetation was sampled in homogenous units with random-systematic method. To do study a total of 140 plots (1×1 m) were placed. In each homogenous unit، 1 to 3 soil samples were taken and topography properties were recorded. Using cluster analysis، the plots with the same species compositions were grouped in unit sub-association. Vegetation was separated to 9 sub-associations. The result of multivariate analysis showed that there was significant correlation between environmental factors (soil and topography) and vegetation. Soil and topography factors together accounted for 30% of vegetation changes. Also، the results showed that soil factors were more effective than topography factors in communities distribution.