آت اكولوژي دو گونه مرتعي Agropyron pectiniforme و Bromus tomentosus در استان مازندران

Autecology of two range plants species of Bromus tomentosus and Agropyron pectlniforme in Mazandaran Province

Providing information about range plant species, to be used as the main basis for managing rangelands, necessitates studying their ecological behavior and relationship with biotic and abiotic components of rangeland ecosystems. In rangeland ecology, this type of studies is considered as autecology of range plant species. This research was conducted to study autecology of two range plant species of Bromus tomentosus and Agropyron pectiniforme in Mazandaran Province. Site characteristics, including topography, climate, soil, and accompanied plant species were determined. For each of the two species, phenology, root system, and their way of presence in the vegetation cover of rangeland ecosystem were examined. The results showed that Agropyron pectiniforme grows in locations with an elevation range of 1200-3000 m above sea level. Soil texture of growing areas is loamy or silty-loam. Soil electrical conductivity (EC) is 0.45-0.94 ds/m, while soil pH is 7 to 7.86. Annual precipitation at its ecological habitats is 320-653 mm; and average annual temperature is 7.2-16.2 degree of centigrade. Canopy cover and frequency for this species were 7.22% and 36.6%, respectively. The root system of this range plant species is fibrous and distributes among soil particles down to the depth of 21 centimeter. Vegetative growth stage of this species starts in late March and ends in late April. Its flowering stage is from early May until early June, and seed ripening is in late June. The results of study on Bromus tomentosus showed that this plant grows in locations with an elevation range of 2300-3300 m above sea level. Soil texture of growing areas is loamy or silty-loam. Soil electrical conductivity (EC) is 0.40-0.72 ds/m while soil pH is 7.21 to 7.47. Annual precipitation at its ecological habitats is 510-653 mm; and average annual temperature is 7.2 degree of centigrade. Canopy cover and frequency for this species were 16.75% and 5.73%, respectively. The root system of this species is fibrous and distributes among soil particles down to the depth of 27 centimeter. Its vegetative growth stage starts in early April and ends in early May. Flowering stage of this range plant is from mid May until mid June, and seed ripening occurs in mid July. Ecological characteristics of these two range plant species need to be considered in management programs ofrelated rangeland ecosystems.