Volume No. 2 Issue No.: 4C Page No.: 840-848 April-June 2008

 

EFFECTS OF SOIL CHARACTERISTICS ON DISTRIBUTION OF VEGETATION TYPES IN POSHTKOUH RANGELANDS OF YAZD PROVINCE (IRAN)

 

M.A. Zare Chahouki*, H. Azarnivand,

Department of Rehabilitation of Arid and Mountainous Regions, University of Tehran, Karaj (Iran)

 

Received on : October, 17, 2007

 

ABSTRACT

 

The objective of this research was to study the relationships between soil characteristics and vegetation in order to find the most effective factors in the separation of the vegetation types in Poshtkou rangelands of Yazd province. After delimitation of the study area, sampling of soil and vegetation were performed with randomized-systematic method. Vegetation data including density and cover percentage were estimated quantitatively in each plot, and with the help of two-way indicator species analysis (TWINSPAN), vegetation was classified into different groups. The topographical conditions were recorded in plot locations. Soil samples were taken at depths of 0-30 and 30-60 cm in each plot. The measured soil variables included texture, lime, saturation moisture, gypsum, acidity (pH), ECe, SAR, and soluble ions (Na+, K+, Mg2+, Cl-, Co32-, HCo3- and So42-). Multivariate methods including principal component analysis (PCA) and canonical correspondence analysis (CCA) were used to analyze the collected data. The results showed that the vegetation distribution pattern was mainly related to soil characteristics such as salinity, texture, soluble potassium, gypsum and lime. Totally, each plant species due to the habitat conditions, ecological needs and tolerance has a significant relation with soil properties.

 

Keywords : Poushtkouh Rangelands, Vegetation type, Soil characteristics, Principal component analysis, Canonical correspondence analysis, Ordination.

 

 

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