classification and ordination of vegetation cover in arid and semi-arid rangelands (case study: nir rangelands of yazd province)

نویسندگان

محمدعلی زارع چاهوکی

دانشیار دانشکده منابع طبیعی، دانشگاه تهران، ایران مسعود یوسفی

کارشناس ارشد سازمان تحقیقات، آموزش و ترویج وزارت جهاد کشاورزی، ایران محمد جعفری

استاد دانشکده منابع طبیعی، دانشگاه تهران، ایران حسین آذرنیوند

استاد دانشکده منابع طبیعی، دانشگاه تهران، ایران مرجان شفیع زاده نصرآبادی

چکیده

the current research was carried out to find out the most effective environmental factors in plant species occurrence by classification and ordination methods. for this purpose, the study was conducted in nir rangelands of yazd province and topography, climate, soil and grazing intensity data of the region were determined. sampling method was randomized–systematic and within each sampling unit 3-5 parallel transects with 300-500 m length, each containing 30-50 quadrates (according to vegetation variations) were established. quadrate size was determined for each vegetation type using the minimal area; hence suitable quadrate size for different species was determined 1*2m–10*10m (2-100 m2). soil samples were taken from 0-30 and 30-80 cm in starting and ending points of each transect. measured soil properties included gravel, texture, available moisture, saturation moisture, organic matter, lime, gypsum, ph and electrical conductivity. to analyze environmental data, classification (using twinspan) and ordination (using pca, cca) were used. the results indicated that soil salinity, texture and available water play the main role in distribution of plant species.

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مرتع و آبخیزداری

جلد ۶۵، شماره ۳، صفحات ۳۶۱-۳۷۸

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