Asghar Farajollahi; Mohammad ali Zare Chahouki; Hosein Azarnivand; Reza Yari; BahraM Gholinejad
Volume 19, Issue 1 , June 2012, , Pages 108-119
Abstract
In this study, the relationship between environmental factors and distribution of plant communities in rangelands of Bijar protected region was investigated. Vegetation types were determined by using physiononmy method. Plot size was determined with minimal area method and after primary sampling the ...
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In this study, the relationship between environmental factors and distribution of plant communities in rangelands of Bijar protected region was investigated. Vegetation types were determined by using physiononmy method. Plot size was determined with minimal area method and after primary sampling the number of plots was determined by statistical method. In each vegetation type, sampling was done along four transects of 300 m length. 15 plots of 1m2 were established along each transect at 20 meter intervals. The type and the amount of existing species and the percentage of vegetation cover were determined in each plot. In each community, 6 profiles were dug within sampling unit. Soil samples were taken from 0-20 and 20-100 cm according to the boundary of separated horizons and type of existing plant species in study area. physiographic features including altitude, slope and aspect were measured and among soil properties, clay, silt, sand, lime, pH, EC, organic mater and gravel were measured. After collecting data, the Principal Component Analysis (PCA) was used to determine relationship between vegetation cover and environmental factors by PC-ORD software. The results indicated that there were relationships between measured factors and distribution of vegetation. Texture, gravel, lime, altitude and slope had the most influence on distribution of plant communities.
Jamal Imani; Ali Tavili; Esaa Bandak; Bahram Gholinejad
Volume 17, Issue 3 , October 2010, , Pages 393-401
Abstract
Analysis of vegetation is one of the important factors in appropriate management of rangelands. The current research was conducted to evaluate canopy cover percentage, forage production, and species density in four areas including reference area, personal rangeland, key area and critical area in the ...
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Analysis of vegetation is one of the important factors in appropriate management of rangelands. The current research was conducted to evaluate canopy cover percentage, forage production, and species density in four areas including reference area, personal rangeland, key area and critical area in the region of village. In each area, 5 transects were established on which 10 quadrate 1 m were used with regard to the plant type and distribution of species. The lengths of each transect and the distance between them were determined 100 m and 20 m respectively according to the species density and distribution. Canopy cover percentage, forage production and species density were recorded in all quadrates. Clipping and weighing method was used to estimate forage production. Data analysis was performed using one way ANOVA and Duncan test. Results indicated that there was significant difference in canopy cover percentage (p≤ 0/1), forage production (p≤ 0/05) and species density (p≤ 0/01) among 4 studied areas. The result showed that with moving from reference to critical area, canopy cover percentage, forage production and species density dramatically decreased as palatable species (class I), average palatable species and non palatable and invasive species had the most canopy cover percentage, forage production and density respectively in reference area, personal rangeland and common area between village and critical area. Perennials and palatable grasses such as Bromus tomentellus and Hordeum bolbosum had the highest canopy cover percentage, forage production and density in reference area. With a gradual increase in grazing intensity, percentage of palatable species decreased while non palatable species like Boisseria squarrosa and Centaurea virgata increased. This research revealed that heavy grazing jeopardized the sustainability of the rangeland ecosystem by creating unfavorable changes in vegetation characteristics.