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Volume 8, Issue 4 (3-2015)
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.
Volume 10, Issue 3 (1-2017)
This study investigated the effects of seasonal changes and different soil conditions on proline, soluble sugars, and ion content of Hammada salicornica in Bafgh area, Yazd province. Three Hammada salicornica habitats with various environmental conditions were selected. The first habitat had salty soil and hardpan (Hamada habitat), the second habitat located next to playa with saline soil and high groundwater table, and the third habitat characterized by sandy soil. The plant samples were collected in four seasons with five replications. The highest Proline content in the species was observed (2.5 mg/gwt) in autumn in sandy habitat and its lowest value was found (1 mg/gwt) in Hamadat habitat. The highest amounts of soluble sugar (2.5 mg/gwt) were measured in summer in sandy and playa habitats and its lowest amount (0.87 mg/gwt) was observed in winter in sandy habitat. The highest amounts of sodium content (42 Meq/l) measured in winter in Hamada habitat and its lowest amount (.64 Meq/l) found in winter in sandy habitat. The highest amounts of potasium (31 Meq/l) were measured in winter in Hamada and sandy habitats and its lowest amount (0.6 Meq/l) were found in all habitats in winter. The highest amounts of nitrogen content (2.6 percent) were measured in Hamada habitat and its lowest amount (1.1 percent) was also found in winter in Hamada habitat. It is concluded that hammada salicornica can adjust its osmotic potential with absorbing and increasing its sodium and potassium content. This study showed that physiological responses of hammada salicornica to environmental conditions depend mostly on plant phenology and the kind of stress as well as their interactions.
Volume 16, Issue 1 (3-2022)
Background and objectives: Over grazing is one of the main causes of rangeland degradation. This problem exist all over the country and during the time and has not been solved by using legal punishments. Lack of attention to grazing capacity has led to the destruction of vegetation. The Payment for Ecosystem Services (PES) for the reduction stock numbers can contribute to rehabilitation of rangeland ecosystems which are getting degraded. An important element of running PES is the Willingness to Accept (WTA) by the rangeland utilizers.
Methodology: the study is conducted in Bardeh and Kresnak regions in Ben city of Chaharmahal va Bakhtiari province. Ranchers were classified and samples to be interviewed were determined. Data were collected through regular and guided interviews and questionnaires. Then two scenarios were created and analyzed. Scenario one was based on the annual profit of each sheep and goat. In the second scenario, the net income from each animal unit was determined by calculating costs and revenues, and the amount of pastoral income decline due to the elimination of one animal unit was determined. The two values calculated in the scenarios were compared and the second scenario, which was more accurate as a quantitative number, was introduced to the respondents. The willingness to pay (WTA) of ranchers in return for the grazing livestock elimination was determined by conditional valuation method (CVM), using the logit function. Role of the law and Existing instructions on PES was investigated by Content analysis method.
Results: Results showed that 71.4% of ranchers agree with PES in return for the grazing livestock reduction. The value of one productive sheep and goat are determined to be 7265 and 6462 thousand Iranian Rials per year, respectively which is lower than the net income per animal unit. The share of the pasture from the net income of a sheep and a productive goat in the permitted utilization conditions, which are set for one hundred days, is 1990 and 1770 thousand Rials, respectively. In the current utilization conditions, the dependence of livestock on rangeland during the year is 44.4%. The outputs of the logit model show that the WTA ranchers increase with the bid price (P = 0.00). There is significant relationship between WTA and the number of grazing livestock (P<0.01). Instructions for terms of rangeland utilization have been prepared and reviewed 5 times. The executive procedure for calculating the customary rights of ranchers has also been prepared and revised by the Cabinet of Ministers in 1391 in 3 times, in 1395, 1398 and 1399, with the approval of its executive regulations. An analysis of the content of these guidelines reveals that is not mentioned payment for ecosystem services.
Conclusion: A comparison between the first and second scenarios shows that the net income of an animal unit in the first scenario is higher than the second. That goes back to the rancher’s assumption in the interview that they will gain more benefits if they claim more animal unit. The minimum level of Payment for Ecosystem Services per animal unit should be equal to that of the profit per animal unit. Investigation of the laws and regulations related to the rangeland shows that yet no law or regulation have been enacted in terms of the PES, in return for the elimination of grazing livestock and even it has not been mentioned in legal terms.
Volume 16, Issue 3 (11-2022)
Background and objectives: Prediction of species richness and diversity patterns are used to develop conservation strategies for biodiversity under regional and global environmental changes. Since modeling the distribution of plant species can provide useful and important information about identifying and introducing potential habitats of plant species, and also few studies have been done in the field of modeling species richness using environmental variables in Iran, so the study of modeling Species richness is important and necessary in the management of vegetation, which is the aim of this research to help rangeland management.
Methodology: This study was conducted in the Sorkh Grieve rangeland with an area of 2620 ha. vegetation and soil sample were taken via random-systematic stratification method. On each slope a transect with a length of 100 meters of was established in the direction of the height gradient and 10 plots were placed along it. Totally 260 plots of 1 m2 were used. In each plot, the list of species, percentage of species cover, and percentage of litter, rocks and number of species were recorded. Three soil samples were taken from a depth of 0-30 cm along each transect and some physical and chemical properties were measured in the laboratory. Physiographic variables were determined in Arc GIS software. Climatic factors were collected for a period of 15 years. Predictive climate variables in this research included annual relative humidity, average annual temperature, and average annual rainfall. The physical and chemical characteristics of the soil such as the percentage of moisture, sand, clay, silt, pH, EC, organic carbon, nitrogen, phosphorus, and potassium were measured. Prediction of species diversity indices of plants was done with two methods: generalized linear model (GLM) and, enhanced regression tree model (BRT). Analysis of the importance of environmental variables for GLM and BRT models was done in the biomode2 package. R2 and RMSE coefficient of explanation were used to evaluate the models. The area under the curve (AUC) criterion was used to compare the performance of these models.
Results: The results of the GLM model showed that altitude, silt, average annual rainfall, nitrogen, and average annual humidity were the most effective environmental factors affecting species richness, respectively. The BRT model results show that the variables of height, soil acidity, average annual humidity, and clay are the most important in species richness, respectively. The results of the GLM model showed that among the richness and species diversity indices, the highest R2 related to the richness index was 0.33. Also, the most important variables affecting this index were nitrogen, acidity, electrical conductivity, rainfall, and humidity. The results of the BRT model showed that among the examined indices, the highest R2 was related to the Shannon diversity index of 0.37. Also, the most important variables affecting this nitrogen index were altitude, clay percentage. and humidity. In general and according to the results, it appears that the environmental parameters affecting richness by the GLM model include altitude, average annual rainfall, average annual humidity, nitrogen, and silt. For the BRT model were altitude, annual humidity, acidity and clay. The evaluation results of the two models showed that the area under the curve (AUC) of the GLM model was 0.61 and the BRT model was 0.72, which shows that the BRT model performed better in modeling species richness in the region.
Conclusion: The result of this research provides good information about the distribution of plant species and affecting environmental factors on their diversity and richness. It is suggested that rangeland managers use the results of this research as well as similar research and give spatial importance to the environmental factors affecting the distribution and richness of species.
Volume 17, Issue 2 (9-2023)
Background and Objectives: The shift from single-purpose grazing to the multi-purpose utilization of rangelands has become important due to increased societal needs and awareness among researchers and stakeholders. Understanding the ecological capabilities and evaluating natural ecosystems are essential for proper management and planning of natural resources. Beekeeping is one potential utilization of rangeland ecosystems, as Iran's four-season climate provides favorable conditions for honey production. However, the lack of knowledge regarding the quantitative and qualitative status of plant species in terms of their value and importance for bees, as well as the absence of effective indicators, hinders proper exploitation of pastures for honey production. This research aimed to investigate and identify the natural and management indicators influencing honey production.
Methodology: Thirteen natural indicators and sixteen management indicators affecting honey production were selected as independent variables using a Likert scale questionnaire. Honey production index was used as the dependent variable. A sample of 67 beekeepers was randomly selected from a population of 81, based on Cochran's formula. Questionnaire validity was assessed by professors and experts, and reliability was measured using Cronbach's alpha statistic.
Results: Statistical analysis using rank mean test in SPSS software revealed that the percentage of nectar-producing and pollinating species had the highest rank (3.14) among the natural indicators, followed by the duration of the flowering period (3.01). Among the management indicators, the type of nutrition consumed by bees ranked first (3.05), followed by the existence of water resources (2.97). Spearman correlation coefficient indicated a positive and significant correlation (99% confidence level) between natural and management indicators. Additionally, Spearman's correlation coefficient and Kendall's tau-b showed a positive and significant correlation (99% confidence level) between natural and management indicators. The percentage of nectar-producing and pollinating species, length of the flowering period, amount of rainfall, cloudiness, pasture condition, and slope direction had a positive and direct relationship with the honey production index. Conversely, the number of migrations, light livestock grazing with bees, and type of ownership had a negative and inverse relationship with the honey production index.
Conclusion: Natural factors were found to have a greater impact on honey production compared to management factors in the study region. To increase honey production, it is recommended for beekeepers to enhance their technical efficiency and knowledge through training and extension programs. They should establish hives in rangelands with suitable vegetation percentage and attractive species for bees, consider rainfall and the availability of healthy water resources, and carefully time hive migrations. Understanding the ecological factors and indicators accurately and implementing proper management strategies can potentially increase honey production by 17% in the region.
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