مجله مرتع
سال هشتم شماره 4 (پیاپی 32، زمستان 1393)

The objectives of this study were to estimate the six macro elements contents Ca, Mg, P, Cl, Na and K in eight species of rangeland forbs Prangus uloptera Medicago sativa, Lotus goeblia, Trifolium montanum, Sanguisorba minor, Stachys inflate, Melilotus officinalis and Ferula ovina used by sheep in Taleghan rangelands sampled in vegetative, flowering and seeding stages. The amount of measured elements in plant species were compared using t-test with a fixed value to ewes and rams need of Fashandi race. The amount of P (3/88 to 12/35 g/kg), Ca (4/05 to 12/88 g/kg), K (12/2 to 29/9 g/kg) and Cl (4/09 to 10/87 g/kg) obtained from plant species at three phenological stages were higher than ewes and rams requirementsd of Fashandi race. For most plant species the Mg (0/54 to 2/12 g/kg) deficiency was observed, and also Na (0/16 to 0/41 g/kg) content of all species at three phenological stages was lower than required level for ewes and rams of Fashandi race. Thus because of critical role of these two elements in livestock vital activities, it is suggested to compensate the deficit of these elements, food supplements should be used (for Na and Mg deficiency using salt and Mg oxide is useful).

Dung beetles are influencing on a wide variety of ecological processes in their habitats. A completely randomized design was used to assess the effects of dung beetles function on dung removal and seeds dispersion in University of Sharekord research station during summer of 2013. The large and small size meshes were used and filled by cattle dung in six treatments with six replications. To evaluate the ecological effects of the insects in seeds translocation, three sizes of plastic beads were used as seed mimics. Data were analyzed by SPSS18 software. Results indicated that the maximum function of the dung beetles was found when dwellers and small tuneller and roller beetles were present but large tunneler and roller beetles were absent. The least dung removal was observed in the control treatment (absent of beetles) and a low possibility of presence of dwellers, large and small tunellers and small rollers as well as absence of large rollers. The maximum numbers of translocated seeds had small size but a few large size seeds were moved by beetles. Overall, the beetles play an important role in dung removal and secondary seeds dispersal in rangelands. The functionality of the beetles are highly affected by many factors and may vary in different seasons, hence further research are required to study the effects of beetles on various livestock dungs in rangelands.

A field experiment was conducted to compare forage production of Medicago sativa and Bromus tomentellus species using factorial experiment based on the completely randomized design with 5 replications in the Fereydoon-Shahr research station, located in west part of Isfahan province in 2012. Treatments consisted of three crop compositions (M. sativa, B. tomentellus or mixture of the two), three density levels including low (4 rows), medium (8 rows) and high (16 rows)) in similar size plots and two planting date seasons (spring and autumn). Results indicated that autumn and spring planting of B. tomentellus and spring planting of M. sativa were more successful. The forage production of M. sativa and B. tomentellus in intercropping was significantly higher than in mono-cropping. The highest biomass production of both species per row was observed in 8 rows density and yield of intercropping per row was higher than mono-cropping per row, either. In the intercropping treatments, land equivalent ratio (LER) values were more than 1 for 8 and 16 rows density, indicated that land-use efficiency in intercropping was higher than in mono-cropping. According to the results, intercropping of M. sativa and B. tomentellus with 8 rows density (30 cm row spacing) is recommended in Fereydoon-Shahr poor dryland fields and similar areas.

This study aimed to evaluate the response of Festuca ovina to some environmental variables using HOF function in Galandrood watershed rangelands located in Mazandaran province. A randomized-systematic sampling was used to establish 150 quadrates of 1m2 along an elevation gradient. Frequency of Festuca ovina, elevation from sea level, slope and aspect were recorded in the all quadrates. Soil samples were taken from 0-20 cm in each quadrates and bulk density, pH, N, EC, organic matter, organic carbon, sand, silt and clay percentages were measured. HOF function with binomial distribution was used to provide the response curves and identify ecological optimum point of F. ovina to the measured environmental variables. The data were analysed using R ver.3.0.2 program. The results showed a monotonically increasing trend for F. ovina frequency to elevation. The optimum frequency and elevation range of the species were 3037 and 2244 – 3037 meters from sea level, respectively. The behavior of F. ovina to EC, organic carbon, sand and slope was a monotonically increasing trend, but its frequency was decreased where the soil clay content was increased. It implies that F. ovina does not prefer heavy soil texture. F. ovina frequeny had a symmetric unimodal response to the soil pH.

Using ecological indicators for assessing and monitoring the ecosystem status is highly important. This study aimed to investigate the effects of some soil and topography properties on functional traits of Stachys lavandulifolia including species leaf area index, leaf dry matter content and plant height in Angemar rangeland. Thirty soil samples were collected from 0-30 cm of soil surface and their physical and chemical characteristics were measured in the laboratory. Chi-square test (Pearson) and multiple regressions were used to analyze the data. According to the results, leaf dry matter of the species was not correlated to the measured physiographic factors (altitude, aspect and slope). There were significant correlations between leaf area index of the species with pH, nitrogen content and sand percentage of soil samples. Results indicated that dry matter content had significant correlations (P<0.05) with pH, organic carbon, phosphorus and clay percentage of the soil samples. There was also a significant correlation between the species height and their leaf area index (P < 0.05, R2= 0.417).

The soil seed bank condition is relatively responsible for variations in rangeland vegetation dynamics. Investigation on soil seed banks is very important where native ecosystems have been converted to other land uses substantially and the size of natural ecosystems are declined. The aim of this study was to evaluate the presence of species in vegetation and soil seed banks in six vegetation types of Behshahr lowland rangeland in Mazandaran province. Vegetation was sampled in 1 m2 plots along 100 m transects. Soil samples were collected from 0-5 cm and 5-10 cm of soil surface. Soil samples were put in germinating pots in the greenhouse and the numbers of seedlings were then counted. Vegetation similarity with soil seed bank was measured using Mantel test and Sorenson index. Results showed that the number of species in vegetation and soil seed bank varied based on the vegetation types. The Halocnemum strobilaceum- Juncus maritimus vegetation type contained 34 species (the greatest number of species recorded between the vegetation types). Twenty six species were also identified in the soil seed bank of Juncus maritimus vegetation type (the greatest number of species in the soil seed bank). Therophytes were the most frequent life form in both vegetation and soil seed bank pools with 31 and 25 species, respectively. Fifteen plant families were found in both vegetation and soil seed banks. The species from Poaceae and Compositae families were dominant in vegetation types but the species from Poaceae and Leguminosae were dominant in soil seed bank. Diversity and richness indices in vegetations were significantly greater than that in seed banks except in Salicornia europaea-Spergularia marina vegetation type. There was no similarity between vegetations and soil seed banks in the whole region and all vegetation types except in Aeluropus littoralis vegetation type.

Livestock grazing and trampling on Astragalus sp habitats can negatively affect gum production potential in these natural habitats. This study aims to evaluate the effect of livestock grazing intensity on gum tragacanth yield in Astragalus gossypinus habitats of Golpayegan, Esfahan province, central Iran. Quantity of discharged tragacanth in each individual plant and above-ground attributes including height from soil surface, canopy diameter and canopy size of corresponding plants were measured using randomized-systematic sampling procedure on all transects in three grazing intensities, i.e., low, moderate and heavy in 2014. Data were analyzed with One-way Analysis of Variance and the means with significant difference were separated with Duncan test. Tragacanth production in habitats with heavy grazing intensity was differed from that in habitats grazed moderately by animals. The quantity of tragacanth secretion in habitats of A. gossypinus with heavy grazing intensity was 54.75% lower than that in the habitats grazed moderately (P < 0.05). Tragacanth yield in heavily grazed habitats was 60.18% lower than that in the habitats with low grazing intensity (P < 0.05). However, gum production in habitats with moderate and low grazing intensities was generally similar (P > 0.05). Correlation coefficient (r) between individual plant height from the soil surface and canopy diameter with the quantity of tragacanth were 0.21 and 0.33, respectively (P < 0.05). In addition, there was a positive significant relationship between canopy size and the quantity of gum in A. gossypinus habitats (r = 0.45; P < 0.05). Livestock grazing affects gum yield in A. gossypinus through changing of above-ground attributes of individual plant particularly in heavily grazed sites.

The science of assessing rangelands is changing as concepts and protocols continue to evolve. Recently, the ecological status concept is currently used by most range professionals as the basis for inventory and assessment. Qualitative assessments of rangeland health provide land managers and technical assistance specialists with a good tool to communicate with the public. The current study investigates efficiency of rangeland inventory with rangeland health method. In this method, 17 indicators were used to assess 3 ecosystem attributes (soil and site stability, hydrologic function, and biotic integrity). Thus, 3 sites with 1464.1 ha included long term exclosure (5years exclosure and refrence site), mid term exclosure (moderate grazing intensity) and overgrazed sites were selected in Goud Jashir of Sepidan, Fars. The results showed that soil stability and hydrologic function were in moderate category and biotic integrity was in moderate to extreme category in mid- term explosure. In overgrazed region, the measured characteristics were categorized as "at risk" comparing with the reference area. Also, indicators such as invasive plants, plant mortality, plant functional/structural groups, soil resistance to erosion and soil compaction were identified as the main factors for rangeland health assessment in the study areas. In other studies the presence of invader plants, soil parameters such as bare soil and stability, species diversity and plant functional/structural groups were reported as the most important indicators in rangeland health assessment.