جستجوی مقالات مرتبط با کلیدواژه « چهارمحال و بختیاری » در نشریات گروه « منابع طبیعی »

Teleconnection patterns can affect climate parameters in different regions of the world. Investigating their effects, especially on the climatic extreme values, can provide appropriate information for optimal management of weather processes as well as terrestrial ecosystems, including vegetation. Temperature is one of the important elements of the atmosphere and is involved in climate changes on a regional and global scale, which quantitatively leads to tremendous events affecting the environment, including increased evaporation and transpiration and plant water needs, increased frequency of droughts, and lack of water resources. The effects of extreme events are often large at the local scale and can severely affect certain sectors and regions. The everincreasing emission of greenhouse gases will cause global warming and cause damages and losses to the water, agriculture, environment, and economy sectors and will have a significant impact on the lives of humans and animals. One of the most important effects of this phenomenon will be the influence on extreme events of atmospheric and climatic elements such as drought, flood, and storm. On the other hand, atmospheric circulations are very variable. These changes lead to the emergence of air patterns and forms of atmospheric currents that occur in different time scales. The teleconnection patterns indicate large-scale changes that occur in the pattern of atmospheric waves and winds and affect the temperature pattern, precipitation, direction of clouds, and position and intensity of the winds in many regions. The effectiveness of these indicators has attracted the attention of researchers in various parts of the world, indicating the importance of these interactions on the atmosphere and surrounding environment. The purpose of present research was to investigate the effect of teleconnection patterns on temperature extreme values (minimum and maximum) in Chaharmahal and Bakhtiari province.

Chaharmahal and Bakhtiari province is one of the mountainous parts of the central plateau of Iran, which has an area of 16421 km2 and is one of the mountainous and rainy provinces of the country, which are the source of two important rivers of the country, Zayandehroud and Karun. This province has one percent of the total area of Iran, which is located in the Zagrosmountain range and in the path of the humid winds of the Mediterranean systems and causes the rise and discharge of these systems. This province has relatively good rainfall. In this research, 8 synoptic meteorological stations of the province in the statistical period of 30 years (1368-1398) were considered. Ten teleconnection indexes were used during this period to investigate their effect on climatic extreme values using Pearson's correlation coefficient.

The changes in average minimum temperature shows that Kohrang station has the coldest minimum temperature in the studied area and annual average fluctuation of this variable has changed from -4.71 to -15.61 degrees Celsius during the studied period. On the other hand, Lordegan station has a higher average minimum temperature than other stations and the range of changes of this variable is from -0.16 to -5.8 degrees Celsius. Lordegan station has the highest values of extreme maximum temperature. The range of changes of this variable fluctuated from 32 to 38.5 degrees Celsius, while the range of these changes for Kohrang station was recorded from 28.7 to 32.2 degrees Celsius during the same period. Based on the results in EGheis and Avergan stations, the average maximum temperature correlation with TNH, NINO3, NINO12, NINO4 and PNA indices was significant at 1% level and with EA/WA, NP and NAO indices at 5% level and had no special relationship with AAO and SOI indices. Among these indices, the highest correlation of this variable with TNH index was 0.728 for EGheis station and 0.71 for Avergan station. At PoleZamankhan and Shahrekord stations, the average minimum temperature correlation was significant at 1% level with TNH, NINO12, and NINO4 indices and with NP, PNA, NAO, and SOI (only for PoleZamankhan station) at 5% significance level. There was no significant correlation with NINO3, AAO and SOI (only for Shahrekord station) and EA/WA indices (only for Kohrang station). The average minimum temperature was significant with TNH, NINO3, NINO12 and NINO4 indices at 1% level and with the EA/WA, PNA, NP and NAO indices at 5% level, and there was no significant correlation with the AAO and SOI indices. The highest correlation coefficient was related to TNH index (0.724) in this station. In Shahrekord and Brojen stations, the average maximum temperature correlation was significant with TNH, NINO3, NINO12, NINO4 and NP indices at 1% level and with EA/WA, PNA and NAO indices at 5% level and there was no significant correlation with the AAO and SOI indices. In PoleZamankhan station, the average maximum temperature correlation was significant with EA/WA, TNH, NINO3, NINO12, NINO4, NAO and PNA indices at 1% level and with NP index at 5% level, and there was no special relationship with the AAO and SOI indices. Results showed that correlation of TNH index with the average maximum temperature of the stations had the highest positive value compared to other indices. The NINO12 index was in the next rank, but its correlation was negative, and it is understood that the occurrence of this index has caused maximum temperature in these stations to decrease. Also, AAO and SOI indices have no significant correlation with this variable in the stations. Also, results reveal that correlation of TNH index with average minimum temperature of the stations had the highest positive value compared to other indices, and the lowest correlation was with Lordegan station and the highest was with Kohrang station. The NINO12 index was in the next rank; but its correlation was negative, and it is understood that the occurrence of this index caused the temperature to decrease at least in these stations. The NINO4 index is also in the third place, with the difference that, like the TNH index, it has a positive correlation in the minimum temperature. The AAO and SOI indices have mainly no significant correlation with this variable in the stations. In Lordegan and Avergan stations, the average minimum temperature correlation was significant with TNH, NINO3, NINO12, NINO4, NAO and PNA indices at 1% level and with EA/WA and NP, NINO3 and NAO indices at 5% level and did not have a significant correlation with AAO and SOI. The highest correlation coefficient related to TNH index was 0.726 and 0.702 for Avergan and Lordegan stations.

In this research, Pearson's correlation was used in 8 meteorological stations in Chaharmahal and Bakhtiari province to investigate the effect of teleconnection indices on extreme maximum and minimum temperature values. In general, it can be said that the teleconnection indices have an effect on the extreme temperature values of the studied area (some have an increasing effect and some have a decreasing effect on these variables). These findings can be used in predicting these extreme values and preventing possible damages to agriculture sector and vegetation. Also, considering the role of temperature values on evaporation and water needs of plants, the results can be used in drought crisis management.

Climate, soil characteristics, topography, land use, and biological relationships at various scales are the most important influencing factors on distribution and ecological niches of species. The climate is one of the most important determinants of plant distribution. Therefore throughout the past ecological history, climate change has had profound consequences on the current conditions of the world's ecosystems, including the existing distribution of species. Changes in the distribution of one species in a given geographical area due to the climate change can lead to shifting the presence regions of that species toward higher elevation that leads up to vegetative restriction or even extinction of the species. Shifting, or changing the geographical distribution of species is a strategy to be resistant to the climate change. Therefore, in order to protect the key ecological and valuable plant species, it is necessary to determine suitable habitats via identifying the most important environmental and human factors affecting the species presence in the current and future conditions. Astragalus L. (Fabaceae) is a genus widely distributed throughout the temperate regions. The Astragalus verus Olivier is a small, valuable shrub with many branches. In addition to its protective role from the point of view of the soil, this species has medicinal and industrial values. In recent decades, the geographical range of the A. verus variety has been significantly declined due to factors such as land degradation and over utilization. Despite the national importance of the Astragalus genus, so far little research has been done on the consequences of the climate change on the distribution of species of this genus. The present study was conducted to accomplish the following objectives; 1) To identify suitable habitats and determin the geographical distribution of A. verus in Central Zagros in the current situation; 2) to predict of the consequences of climate change by 2050 and 2070 under different scenarios on geographical distribution of A. verus; 3) to determin the most important factors affecting the distribution of this species. distribution of A. verus; 3) to determin the most important factors affecting the distribution of this species.

 This study was carried out in Chaharmahal and Bakhtiari province in an area about 1.65 million hectare thai is totally located in Central Zagros region. Extensive field studies were integrated to collect geographical coordinates of the presence point (112 points) of this species by using Global Positioning System (GPS) throughout Chaharmahal and Bakhtiari province. Bioclimatic (bio1–bio19), Physiographic variables (elevation, aspect, and slope) and land cover/land variables were used for modeling. Before modeling, two methods of Pearson correlation analysis and Variance Inflation Factor (VIF) were used to check out the correlation between the various environmental variables. In order to model, 19 environmental variables including bioclimatic variables, physiography and land cover / land use were applied to model the distribution based on correlation analysis. Variables with Pearson’s correlation coefficient, r2<±0.8, VIF<3) were selected. Finally and after the omission of the layers having high correlation, nine variables were used for modeling. In order to predict the distribution of the suitable habitats of the Astragalus verus Olivier, Biomad2 software package in R environment (3.1.2 version) was used. In this study, ensemble methods including Maximum Entropy (MaxEnt), Artificial Neural Network (ANN), Generalized Boosting Method (GBM), the Generalized Linear Model (GLM), Flexible Discriminant Analysis (FDA), Random Forest (RF) and Multivariate Adaptive Regression Splines (MARS) were used to estimate the suitable habitats. We used 80% of the occurrence points as training data for model calibration and 20% of the rest of the data set to evaluate the predition of the models. Prediction of the geographical distribution of the Astragalus verus Olivier in the future (years 2050 and 2070) was made based on four scenarios of the increase in the greenhouse gases (Representative Concentration Pathways; RCPs) RCP2.6, RCP4.5, RCP6, RCP8.5 in general circulation model MRI-CGCM3. Model performance was assessed by using the area under the receiver operating curve (AUC) and the true skill statistic (TSS).

 Our results revealed that the most effective variables in desirability of the study species habitat were the isothermality, mean temperature of the wettest season of the year and seasonal precipitation variables respectively. In keeping with the findings, the Astragalus verus Olivier mostly exists in habitats with Isothermality (bio3) from + 36.8 to + 39.7 °C, Mean Temperature of the Wettest season of the year (bio8) from - 2 to + 3.5 °C, and seasonal precipitation variables (bio15) from 100 to 112 mm and the Annual Precipitation of 280 mm to 490 mm. Based on the results of modeling of current conditions, in comparison to the other regions, northeast and east of the province had the most habitat importance for the Astragalus verus Olivier. Our findings show that about 27.43% of the study area was identified as suitable habitats for the Astragalus verus Olivier. Prediction of the geographical distribution of the Astragalus verus Olivier in the future (years 2050 and 2070) was made based on four scenarios of the increase in the greenhouse gases (Representative Concentration Pathways; RCPs) RCP2.6, RCP4.5, RCP6, RCP8.5 in general circulation model MRI-CGCM3. Based on the future projections were made for the year 2050 and 2070 with four Representative Concentration Pathways (RCPs) scenario (2.6, 4.5, 6 and 8.5) and general circulation model MRI-CGCM3. In keeping with our findings, climate change can have significant consequences for the Astragalus verus Olivier suitable habitats in the study area. Based on various senarios, about 45.70 percent (year 2050, RCP2.6) to 89.88 percent (year 2070, RCP8.5) of the current habitats for the Astragalus verus Olivier will be unsuitable due to the climate change by 2050 and 2070. While in the same period of time, about 1.58 (RCP8.5, 2050) to 13.19 percent (RCP2.6, 2070) may be added to the suitable habitats of this species in areas with higher elevation. According to all scenarios, the suitable habitats of this species will decrease in all habitats, especially in areas with lower elevation. The climate change consequences especially the probability of decling and shifting the geographical range of the plant species in various habitats of Iran especially in the central Zagros and also in Central Iran range are predicted. Assessments showed that the models had acceptable accuracy and Random Forest model was determined as the most reliable model to predict the distribution of this species.

 Generally, this study indicated that ensemble model might predict the potential distribution of the Astragalus verus Olivier with a relatively high accuracy (AUC= 0.92 and TSS= 0.79). The scenarios used in this study predict the probability of the shift of the geographical range of the studied species under climate change scenarios of 2050 and 2070. According to the results, it seems that the suitable habitat extent of the Astragalus verus Olivier in the study area has been decreased and will shit toward the higher elevation. Although land degradation and over utilization may be considered as two important factors in habitat degradation of this species but this study highlights the importance the effects of climate change on the distribution of the Astragalus verus Olivier. As a result of the severe and inappropriate harvest of the Astragalus verus Olivier, the range of its distribution and density has decreased in some areas, which has increased the intensity of phenomena such as soil erosion. This issue requires a double attention of the managers and experts of natural resources to the Astragalus verus Olivier and the other species with similar performance in ecosystems having importance from the view point of economic productivity as well as their ability to conserve the soil.

In this study, different produced extruded commercial fish feeds in Chaharmahal-V- Bakhtiari Province investigated with the aim of determining growth indices and carcass composition of fingerlings rainbow trout. Total of 3600 rainbow trout Juveniles with initial average weight of 80±2.4 gr, were subjected in triplicate to four diets of 1, 2, 3 and 4 and in a completely randomized design for 130 days. At the end of experiment, 10 fish (294.77.3 g) from each tank were randomly sampled and chemical carcass composition (i.e. protein, lipid, ash and moisture) were measured. The highest body weight gain and daily weight gain were calculated in treatment 1 compared to others (p<0.05). Food conversion ratio (FCR) were lower in both 1 and 3 treatments than other groups (p<0.05). The maximum crude protein of fish fillet was obtained in treatment 1 and the lowest was measured in treatment 2 (p<0.05), but the fat content had not any significant differences among treatments (p>0.05). The highest and lowest fillet ash percent was seen in treatments 1 and 2, respectively (p<0.05). Treatments 1 and 2 were contained the highest and lowest amount of calcium and phosphorous, respectively (p<0.05). In conclusion, growth performances and carcass chemical composition of rainbow trout were not similar which could be related different levels of crude protein of commercial diets, which produced in Chaharmahal-V-Bakhtiari feed factories.

Tooba scheme is one of project upon which national, public and personal fertile lands has been allocated to develop farming and garden products in order to optimize utilization of massive capital of country's soils and waters, increase production, create jobs and increase revenue. Therefore, this study has been done with the aim to investigate the economic, social and environmental effects of Tooba scheme in Chaharmahal and Bakhtiari Province. In order to achieve the objectives of this study, data was collected from a sample including 141 Jihad-e-agricultural experts and garden beneficiaries in Chaharmahal and Bakhtiari Province through random sampling method. A questionnaire was used to collect the data. Data analysis was performed by using SPSS20 software. The results based on descriptive analysis showed that the majority of beneficiaries were not satisfied with transfer manner of Tooba scheme. Also, the result based on inferential analysis showed that Tooba schem has improved environmental conditions. In addition to there is a significant differences view between Jihad-e-Agriculture experts and beneficiaries who have not participating in Tooba schem with Tooba schem beneficiaries about the improvement of economic conditions. Also investigation the social conflict effects indicated that there is a significant difference between beneficiaries who have not used Tooba scheme with Jihad-eAgriculture experts and beneficiaries of Tooba scheme.

Formalin is used as a therapeutic solution on the fish fertilized eggs in the hatchery of rainbow trout farms. In this research, the risk of current formalin use on the health of exposed workers in the hatcheries of rainbow trout farms of Chaharmahal va Bakhtiari prov. (the south -west of Iran) was evaluated. This report focuses on three operation authorizations basis of 11 hatcheries consists of the workers’ total information about the formalin health hazards, the necessary considerations during accidental formalin leak or considerations of the occupational individual health preservations during formalin use, and so the provided and established instruments in the hatcheries to protect the workers and reduce accidental releases harms to public and the environment. The study relies that all the workers were improperly operated formalin not only with the unnecessary dosage but also with the unsuitable (no laboratory) equipments. There is only one case of applying suitable gloves (not latex gloves) and 33 % simple mask ventilation among the users as the simplest hazard protection approaches; however 100%, 70.8% and 91.7% of them have declared irritation of the nose and throat , coughing and temperate non-sense of the fingers, respectively. The personal knowledge about carcinogenetic, tissues fixative attributes of formalin, and its flammable-combustive characteristics were 16.7%, 62% and 33 %, respectively. None of 11 farms have provided equipments for 5 predicated accidents as first medical aids and rescue for fire (except for two fire suppression chamber).There is evidence of high risk of the formalin use about ecological, public and human health because of unsuitable management system of safety basis and environmental protection requirements in the rainbow trout farms.