Mohammad Jangju; Fereidoon Mellati; Zohreh Atashgahi; Majid Vatanpour
Volume 20, Issue 1 , June 2013, , Pages 145-160
Abstract
Autecology of three range plant species, i.e. Prangos latiloba Korov., Convolvulus commutatus Boiss, Stachys trinervis Aitch., was studied in the Northern Khorasan Province. These species provide forage for the grazing livestock in the rural rangelands, especially on the sheil formations. Geographical ...
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Autecology of three range plant species, i.e. Prangos latiloba Korov., Convolvulus commutatus Boiss, Stachys trinervis Aitch., was studied in the Northern Khorasan Province. These species provide forage for the grazing livestock in the rural rangelands, especially on the sheil formations. Geographical distribution was studied, in addition to topography, soil characteristics, and climate conditions of their natural habitats. Forage quality was assessed by measuring crude protein, ADF, NDF, dry matter, and ash. S. trinervis was growing in most of the rural rangelands, on the conglomerate, sandstone and shale formations, and under the arid and semiarid climate conditions. All species started their yearly growth at early April. For P. latiloba and C. commutatus, flowering and seed ripening stages similarly occurred at the early June and early August, respectively. For S. trinervis, phenological stages were overlapped, in which flowering, seed ripening and seed shedding were simultaneously found from the early May till early September. There was a sharp reduction in crude protein and increase in ADF and NDF factors, which led to significant reduction in the forage quality of all three species. The major limiting factors on geographic distribution of C. commutatus were: its high forage palatability and quality which had led to high effect of livestock grazing. For P. latiloba the main limiting factors were seed predation by pests and herbage harvesting by farmers. On the other hand, higher distribution of S. trinervis was due to having higher essences, lower palatability, overlap of phonological stages, and probably higher adaptation to climate and soil conditions.
Maryam Nikan; Hamid Ejtehadi; Mohammad Jangju; Farshid Memariani; Hajar Hasanpour; Fariba Noadoost
Volume 19, Issue 2 , September 2012, , Pages 306-320
Abstract
Livestock grazing is one of the most influencing factors on the rangeland community structure and composition, which can also change the vegetation diversity. The main aim of this research was to survey the flora and plant biodiversity at three rangeland sites, being used under different grazing intensities, ...
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Livestock grazing is one of the most influencing factors on the rangeland community structure and composition, which can also change the vegetation diversity. The main aim of this research was to survey the flora and plant biodiversity at three rangeland sites, being used under different grazing intensities, Baharkish, Quchan, Iran. Three sites were systematically selected along a spatial gradient of low, moderate and high grazing intensity, and 20 quadrates were randomly established within each site. Species composition, abundance and canopy cover were recorded within the quadrates. Simpson and Shannon diversity and Carmago and Smith & Wilson evenness indices were measured for each site. Floristic studies led to the identification of 156 plant species belonging to 34 families. The floristic composition of the area was strongly dominated by the Irano-Touranian elements. Shannon and Simpson diversity indices were significantly higher under the moderate than the low and heavy grazing intensity sites and the lowest diversity was significantly recorded for the heavy grazing site. Evenness indices did not significantly differ between the low and moderate grazing sites, but it was significantly lower under the high grazing site. In conclusion, proper livestock grazing is necessary for preservation of species diversity in the semiarid rangelands; Moderate grazing maintained the species diversity while light and sever grazing reduced or even eliminated some sensitive plant species.
Mohammad Jankju-Borzelabad; Mahdeyeh Tavakkoli
Volume 15, Issue 2 , January 2008, , Pages 215-226
Abstract
Due to the increasing attentions on multiple uses from rangelands, methods of improving seed germination rates were investigated on 10 arid rangeland species, which have ornamental and/or pharmacological values. 9 dormancy breaking treatments were applied, in a completely randomized design. Seeds ...
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Due to the increasing attentions on multiple uses from rangelands, methods of improving seed germination rates were investigated on 10 arid rangeland species, which have ornamental and/or pharmacological values. 9 dormancy breaking treatments were applied, in a completely randomized design. Seeds were then located in an incubator and daily germination rates were recorded. Between treatments, gibberlic acid caused the greatest influence, on germination of 5 out of 10 species. Low temperature, potassium nitrate, high temperature, sulphuric acid, and water imbibitions also increased germination rates of 3, 3, 3, 2, and 1 species respectively. Lowest effect was found for polyethylene glycol and wet sand treatments. The applied treatments led to high increases in germination rates of Stachys inflata, Pteropyrum aucheri, Capparis spinosa and Fortynia bungei. However, the results for Atraphaxis spinosa, Calligonum polygonoides, Calligonum bungei, Isatis cappadocica, Glaicium oxylobum, and Iris songarica may not be applicable for field workers, because of low (0-5 %) germination rate of these species, while they are valuable for researchers. Further interesting results of this experiment was a logical relationship between treatment that caused the highest increase in germination rate, and phenology stages, habitat conditions of some species.