Journal of Rangeland
Year:2019 | Volume:13 | Issue:1|Papers Count:10

This research aimed to evaluate the effects of cultivating time (spring and autumn) on some morphological traits of ten genotypes of 5 species of Astragalus including Astragalus brevidens, Astragalus lilacinus, Astragalus cyclophylon, Astragalus subsecondus and Astragalus vegetus in Homand Absard rangeland research station. A completely randomized design was used to cultivate the genotypes in three replications on two lines of two-meter length with a row spacing of 0. 5 m for each genotype and 0. 75 m for different species. Forage production, canopy cover percentage, canopy diameter and height, seed yield, and the number of flowering stems of the species were measured. Analysis of variance and Duncanchr('39')s Multiple Range Test were performed for mean comparisons. According to the results of the third year of cultivation, the two treatment groups (spring and autumn) showed significant differences in terms of the measured traits and genotypes. Although autumn cultivation caused an increase in forage production, canopy cover percentage, height and the number of flowering stems, their seed yield did not vary significantly. A. vegetus (Gharebagh and Kurdistan) and A. brevidens (Tandure and Torogh) genotypes had the maximum performance for all the measured traits. A. vegetus (Kurdistan) genotypes with 2740 kg/ha forage production and producing appropriate canopy cover had the best performances compared to the other species. Results showed that autumn is the best time to cultivate these herbaceous species from the Astragalus genus. The findings of this study are applicable for restoring degraded semi-arid rangelands with annual precipitating more than 300 mm.

The main goal of this study was to evaluate the ecological potential for both range management and conservation management based on the current models and EMOLUP model in Firozabad County. We evaluated normal range management potential by considering topography criteria and conservative range management with excluding topography criteria from the evaluation. We compared the results of various land-use planning methods including arithmetic mean method, Makhdoom method, maximum limitation proposed method, the geometric mean method, eco-socioeconomic model of land-use planning (EMOLUP), the calibrated version of EMOLUP, simple weight arithmetic mean, weight arithmetic mean with considering limiting factors and its calibrated method. We used four indices to evaluate the accuracy of the models including kappa coefficient, overall accuracy, and average accuracy. Results indicated that EMOLUP and its calibrated version were the best methods for land-use planning for normal range management and conservative range management, as these methods had the highest Kappa coefficient and overall accuracy. The Makhdom method yields the lowest accuracy with a kappa coefficient of zero in determining the ecological potential for range management in the study area.

Climate change affects various activities of humans through its impacts on ecosystems and human-environment relationships. To gain a better understanding of these impacts, this study aimed to analyze the impacts of climate change on perspectives of pastoralists, and their activities in Haraz river basin (HRB). We also suggested some adaptation techniques and recommendation for reducing the impacts of climate change on livestock production. At the first step, the impacts of climate change on activities of pastoralists were elicited using questionnaire from local pastoralists. Discriminant analysis was used for calculating the distance between pastoralistschr('39') opinions in STATISTICA software. Also, the Mann-Whitney test was used to compare the perception of pastoralists about climate change in Baladeh and Larijan. According to the results, a significant proportion of pastoralists believed that climate change has occurred in HRB. We also found that there is a strong agreement between the perspectives of the two group pastoralists of Baladeh and Larijan about changes in climate characteristics. Mean comparison showed that pastoralists believed that climate changed posed significant changes in the sale of livestock and percent of sheep in herd composition (α = 1%). The Discriminant analysis revealed that 99 % of the perception of the two groups about climate change were similar. They only disagreed at 1 % about the effects of climate change on sales rate of livestock and percent of sheep in herd composition. In conclusion, providing pastoralists with enough and proper extension services by planners and authorities of natural resources to cope with climate changes seems vital to ensure sustainable local livelihoods.

Smyrnium cordifolium is an aromatic and endemic plant species belonged to Apiaceae family. This study aimed to compare the essential oil composition of S. cordifolium in different natural habitats in Gorgo, Mahmudabad, and Darshahi in Boyer Ahmad County. The species were collected, dried and their essence was extracted using the distillation method (Clevenger apparatus). GC-FID and GC/MS devices were used to separate and detect the chemical components of samples. According to the results, the essential oil contents of various habitats varied significantly. The average yield of essential oil from Gorgo, Mahmudabad, and Darshahi were measured as 0. 25%, 0. 17% and 0. 22%, based on the dry weight of the plant (weight/weight), respectively. The chemical compounds of essential oil of the species include curzerene (45/7 %), menthofuran (29/8 %),   Elemene (29/1 %), aromadendrene (20/6 %),   Cedrene (16/9 %) and germacrene-D (16/5 %). Results indicated that curozurene is the most common identified components in the essential oil of the species. Alpha-sodium in the Gorgo habitat was the least and common components in the habitats. According to the findings of this study, the quantity and quality of essential oil extracts of S. cordifolium are different in various habitats and are influenced by environmental factors.

The short-term effects of fire on vegetation changes were studied in Khosbijan station rangelands, which was burnt in 2015. A systematic-randomized method was used to collect data in late May 2016 and 2017. Sampling was carried out in the burned site, with a nearby non-burned site (as control). Vegetation characteristics such as cover and density of shrubs, perennial and annual grasses, perennial and annual forbs, and forage production were measured. The paired T-test was used to compare burned and unburned sites vegetation properties. A total number of 80 vascular plant taxa belonging to 25 families and 72 genera were identified. Asteraceae (with 17 species), Papilionaceae (with 12 species), Poaceae (with 7 species) were the most common plant families in the study area. Therophytes and Hemicryptophytes were also identified as the most life form in this area based on the Raunkiaer classification system. The floristic composition of the area is strongly influenced by a large number of the Irano-Turanian elements. The results showed that density, cover percentage and forage production of perennial and annual forbs, and annual grasses were increased significantly in the burned site. In contrast, density and cover percentage of shrubs decreased in the burned site. Our results revealed that density, cover percentage and forage production of species with various palatability (e. g. I, II, and especially III) increased in the burned site compared to control site. Overall, our results indicated that fire changes the vegetation properties based on the existing floristic composition and range condition. Therefore, fire occurrences do not lead to a better forage quality in all conditions.

The effects of plant density and water stress on leaf water potential and soil water content of Medicago sativa and Bromus tomentellus were studied. A greenhouse experiment was conducted at the Isfahan University of Technology. The experiment included 18 treatments, three crop compositions (M. sativa, B. tomentellus or a mixture of the two), two plant density levels (2 and 4 plants), three watering regimes and four replicates, arranged in a completely randomized block design. Results showed that leaf water potential of M. sativa and B. tomentellus decreased significantly (p < 0. 05) with increasing drought stress and plant density in all treatments. The leaf water potential values of the studied species were different. In mixed cropping, the leaf water potential of B. tomentellus was more negative than M. Sativa due to its drought resistant. Also, with increasing soil depth, soil water content decreased in mixed cropping compared to M. sativa mono-cropping and B. tomentellus mono-cropping. B. tomentellus with fibrous root system could only absorb surface soil water content but M. sativa with a well-developed taproot system could absorb a greater amount of soil water content of deep soil. Therefore, the two species functioned complementarily and increased the efficiency of the mixed cropping.

Identification of plant characteristics in response to various ecological condition is essential for understanding vegetation dynamics. Verbascum speciosum is one of the most important medicinal species for infectious diseases. This species is spread in rangelands of Iran and especially in Azerbaijan. This study aimed to evaluate the ecological and morphological characteristics of V. speciosum in four range places in Sahand Mountain. A systematic random method was used to collect vegetation and soil data. Six transects with a length of 100 meters were established in each place and the vegetation data were collected from 60 plots with a size of one square-meter, placed along each transect. Structural and biomass characteristics of ten plant species of one year and two years old were recorded in each range place. Redundancy analysis (RDA) as a linear method was used to investigate the relationships between species characteristics and environmental factors. According to the results, various environmental factors affect biomass and structural characteristics of the species. Results indicated that as altitude increases and consequently temperatures decreases, the structural characteristics of one-year-old of V. speciosum decreased. Increasing soil moisture and decreasing oil lime content lead to an increase in the structural characteristics of one year old of the species. Two-years old species had better structural and biomass performance in places with lower elevation and sandy soil texture compared to the one-year-old of the species. The importance of structural and biomass characteristics varied based on the species application for different purposes. The structural and biomass characteristics of V. speciosum are correlated to each other positively. Measuring these characteristics are required for quantifying functional diversity of rangelands.

The effects of uncontrolled fires on natural ecosystems and the factors affecting their occurrence are widely studied worldwide. Fire occurrence modeling is important to prioritize the fire risk in a given area and identify practices to prevent it from happening. The purpose of the present study was to simulate the prediction of fire and identify the most important factors in fire occurrence using Bayesian Belief network in Chaharmahal and Bakhtiari Province. Data from 205 fire sites and 205 sites with ‘ no-fire’ experience were recorded. Climatic factors (e. g. annual precipitation and annual mean temperature), topography (elevation, slope, direction), land cover, and human factors (e. g. distance from the residential area, distance from agricultural land and distance from the road) of the sites were selected and embedded into the BBN model. The results indicated that the ability of the BBN model to predict the occurrence of fire was excellent (AUC= 0. 923). Since there are many fire events in this province, the results of this study can be used as a fundamental and powerful tool for decision-makers to reduce the incidence of fire and its hazard.

Iranian government supports qualitative and quantitative development of medicinal plants because illegal and severe harvesting have seriously damaged their production in natural areas. This study aimed to evaluate the tendency of local communities for producing medicinal plants in forest and rangeland of Kamalan region, Golestan province. Interviews and questionnaires from the specific group of people familiar with medicinal plants including range managers, farmers, and villagers were used to collect the data. The validity and reliability of the questionnaires were approved by a panel of experts and calculating the Cronbach alpha coefficient, respectively. The tendency status of local for producing medicinal plants was regarded as an independent variable, while the age, occupation, secondary job, education level, farm area, and responsibility in the community were considered as dependent or predicted variable. The Logistic regression was used to explore the relationship between independent and dependent variables using SPSS 23. Results indicated that knowledge about the effects of medicinal plants on diseases, and land ownership had a positive (B= 12/12) and negative relation (B=-11. 27) to the tendency of locals for producing medicinal plants, respectively. The result showed that the main positive and negative effective factors on local communities tendency for producing medicinal plants were knowledge of medicinal plants properties and land ownership, respectively (p <0. 05). Providing facilities, extension workshops, and investing in cultivating medicinal plants can engage more people to medicinal plant industry. Policymakers can use the result of this study to monitor and enhance the tendency status of locals for producing medicinal plants.

The increasing rate of greenhouse gases release such as carbon dioxide from soil to the atmosphere posed serious concerns in the world over the past few decades. Carbon dioxide gas is identified as one of the important factors responsible for accelerating greenhouse effect, global warming and climate change. Closed chamber method was used to evaluate the effects of various grazing pressure on the rate of carbon dioxide emission. The amount of CO2 emission was measured on a monthly bases for a period of one year in Ghoshchi Rangelands of Urmia, West Azerbaijan province. The factorial analysis revealed that severe grazing pressure leads to the highest mean of carbon dioxide production (4. 2 g/m 2 / day). The highest average amount of carbon dioxide was produced in August and July (4. 42 and 4. 13 g/m2/day). The lowest CO2 production was observed in February and December (0. 51 and 0. 55) in grazing exclusion site. Increasing soil microorganisms activity is responsible for increasing CO2 emission. Severe trampling in the highly grazed sites leads to an increase in the compactness of soil surface and erosion, and alter the water content and temperature of the soil surface and ultimately increase CO2 omission. This study highlights the impacts of severe grazing pressure on CO2 omission; hence, policymakers and range managers should take specific management practices to reduce grazing pressure to prevent CO2 accumulation in the atmosphere.