جستجوی مقالات مرتبط با کلیدواژه "تالاب میقان" در نشریات گروه "محیط زیست"

Nowadays, monitoring the wetlands land-use change trends using satellite images is one of the most important tools for managing and conserving wetlands. The goal of this study was to investigate land cover change in Meighan wetland as a remarkable wintering wetland for water birds and waders in the middle of the country during 2008-2018 in order to evaluate the trend of the changes in this wetland and make managers prompt a proper decision for the effective management. In this study, images of the geo-referenced Landsat satellite, ETM+, OLI 8 TRIS were used and after applying necessary corrections on the images, results were analyzed in the ENVI 5.4 software. The results of the change detections indicated that the area of the wetland has decreased by 63.31% during the study period. Vegetation covers of the wetland diminished by 64%. During the study period, barren lands have increased by 11.6%. Also, the area of agricultural land in the border of the wetland has expanded by 23.15%. Besides, reviewing water birds and waders abundance in 2008 and 2018 showed that abundance of the most families of water birds and waders were higher in 2008. Taking the environmental importance of Meighan wetland into account as a place hosting large populations of water birds and waders, we recommend that management plans to survey and systematically control of this wetland should be implemented.

Radionuclides are naturally occurring in water, soil, plants and air, and today, industrial and urban pollutants are also effective in increasing its level. As part of this research, the impact of Arak wastewater treatment plant production on environmental radiation in the Meyghan wetland entrance area was examined.

In this study, 10 sediment samples, 10 water samples and 10 reed samples from the water input zone from the Arak wastewater treatment plant to Meyghan wetlands were collected. The specific activities of radionuclides were determined using gamma ray spectrometry method employing high purity germanium detector (HPGe) and maps of the distribution of radionuclides in this area were prepared for sediment and water samples.

The average values ​​of specific activity of 226Ra, 232Th, 40K and 137Cs in sediment samples were 22.86, 27.26, 409.04 and 6.34, and in water samples 2.67, 3.04, 23.7 and 0.37 as well as in reed samples 8.8, 9.59, 45.66 and 2.26 in Bqkg-1, respectively. The amount of radium equivalent activity in sediment samples ranges from 84.14 to 104.55, with an average of 93.34 in Bqkg-1.

The average Raeq value in the sediment samples obtained as 93.34Bqkg-1, which is less than the global average (139.7Bqkg-1). It seems that the pollutants are removed from the water taken in calm ponds and the treatment section by active sludge, and the water entering the wetlands contains a small amount of radioactive contaminants.

Meighan wetland is one of the valuable wetlands of Iran in Markazi Province which is known as an important wintering habitat for the common crane (Grus grus). This desert wetland has faced with several environmental challenges, in the last two decades, due to successive drought and the lack of proper management. In the current study, modeling of habitat suitability for the common crane was conducted in Meighan wetland and aquatic ecosystems of Markazi province, using 38 presence points of the crane and with nine environmental variables (climate, vegetation cover, slope, elevation, land use distance to road, rivers and villages) in maximum entropy model (Maxent). In addition, habitat destruction factors were prioritized using a hierarchical analysis process (AHP). The area under the curve (AUC) of the model was estimated 0.997, showing the high accuracy of the model. Three areas were selected as suitable habitats for the common crane including, Mighan wetland, Kamal Saleh Dam in Shazand and 15- Khordad Dam in Delijan city. An area of 4360 hectares equals to 18 percent of Meighan wetland was classified as suitable habitats for the common crane. Suitable habitats were located on the coastal margin of Meighan wetland. Central parts of the wetland and areas far from the wetland were classified as unsuitable habitats. Environmental variables including land use, vegetation type and distance to the roads accounted for the highest contributions to the model. Habitat destruction factors were prioritized using a hierarchical analysis process (AHP). The results of AHP indicated that three factors including road construction, human settlements and land use changes were the most damaging factors with the highest weights. These factors have priority for habitat restoration to improve the ecological habitat of this species.

Meighan Wetland Forbidden Hunting Region of Arak is located at center of Iran in the birds’ migratory flyway. In the cold season, thousands of the migratory birds settle this region featuring of the desired habitat conditions annually, especially, common crane. To view are the birds fauna 4 stations with diverse habitat conditions ranging from Waterfowl, The aquatic, playa and desert shrubs. They Were selected as the location for viewing. Bird watching was performed during the season from spring of 1392 until winter of 1394.In order to, collect the data was used directly observed and counted birds. During the study were identified bird species 150 from orders13 and families 38. As if of these was observed respectively species 77 of Waterfowl, The aquatic and Terrestrial 73. The number of observed species were endemic species 60, species 90 of migratory and semi-immigrant and immigrant passing. Order passeriformes with the largest number of families(families12) and with the largest number of species (species 41) were identified most diverse orders in the region. In the area, the species of Aquila nipalensis, Oxyura leucocephala and Falco cherrug are endangered in the category

Meighan wetland of Arak is located in the central part of Iran country, in the vicinity of Arak metropolis and in an arid and semi-arid region. Meighan wetland with environmental Functions and values of useful is exposed to environmental threats and destructions of severe. To prevent from this threat and destruction of the Meighan wetland is need to a correct recognition and evaluation of this area, It's necessary to introduction of a logical plan for access to a sustainable development. This study will identify causal chains of land degradation of Meighan wetland and sustainable development with driving force-pressure-state-impact-response (DPSIR) model. This model defines the association between environmental processes and environmental impact with human activities. The results show, the most significant driving forces in Meighan wetland are includ: population increase, drought aggravation and increas demand for water, cause of pressures such as expansion of dams, well drilling, air pollution and mining, Meighan wetland environmental state has encountered with more drought and salty dust. Effects have on the increase of air pollution, disease and popular protests. Consequently, responses are the sustainable development program with priority of the driving force, pressure, status and effect at the basin and sub-basin levels. Important programs are includ: Access to integrated management with the participation of all stakeholders, area environmental capability, restore and protect wetland, and ecotourism.

Due to its location in a semi-arid and dry region and proximity to major wind erosion centres, especially Meighan desert and wetland, the mega-city of Arak is facing the problem of air pollution. The main objective of this study is the identification of sources of and tracking dust storm routes entering Arak metropolitan area from domestic sources using the HYSPLIT Model. The present study was carried out using HYSPLIT model, NAAPS model, MODIS satellite imageries and GADS weather data from the NECEP weather prediction centre for 22 June 2016 (2 Tir 1395). The modelling was performed using a retroviral tracking method for identifying the motion direction of dust particles in three stations with a height of 10, 200, and 500 metres, respectively. The research results demonstrated that most frequent motion directions not only cross the Kashan and Qom desert lands and are, thus, a source of dust storms but also cross Meighan dessert wetland and its surrounding desert lands which are the main source of dust particles of the mega-city of Arak. The forward direction of dust particles transported from Meighan desert wetland and Kashan Qom desert lands over a distance more than 400 km towards the Northwest of Iran influences the air quality index (AQI) of cities such as Arak, Shazand, Hamedan and even Sanandaj. These findings are in agreement with the optical depth of dust particles and the amount of surface dust in terms of the NAAPS model and the suspended particle concentrations in the cities located on the direction of particle dissipation. Also, these results are in accordance with the previous studies in terms of erosion assessment, indicating that the numerical models have the ability for tracking and identifying sources of dust storms satisfactorily.

Due to extensive threat factors facing the global biosphere as well as a lack of adequate conservation funds, we need to develop more efficient methods of conservation management in accordance with a comprehensive vision of biodiversity and that reinforces ecosystem-based actions. Meyghan Wetland which shows high ecosystem values as well a wide range of threat factors was selected as a case study. As a transitional zone as well being diverse habitats, the wetland has covered a wide range of diverse plants and animals in the aforementioned area. Due to its natural potential for establishing an Important Bird Area (IBA) as well as designation as an international wetland, the importance of this area from the ecological and ecotourism point of view has increased. Moreover, the absence of the permanent streams, drought events, overharvesting of the underground waters, changes in the hydrologic gradient, decline in the water quality, the influence of chemical pollution, erosion as well as the lack of any appropriate program for land use planning has created several environmental challenges in the aforementioned region. Therefore, compilation and assessment of the basic ecological data, accompanied by an appropriate management plan, can be effective for the management of this wetland.

Revealing changes is one the most fundamental needs in the management and assessment of natural resources. With regard to remote sensing images، it is then possible to prepare land-use change maps، which are the result of the change detection processes. It should be noted that different methods have been presented to detect changes and developments of land-uses. The purpose of this study is prepared Mighan wetland –land use mapping in 2013 and Comparison of supervised and fuzzy classification methods. In this study، Mighan Wetland changes as well as its land-use and land-cover improvements were obtained through using OLI Landsat satellite images in 2013. Then، the images were geometrically and radiometrically corrected using appropriate algorithms. Subsequently، training samples were classified in five land-use classes based on fuzzy and supervised classification methods. After applying fuzzy classification and land use map was prepared on the Satellite image OLI. The classification accuracy was evaluated were to do a statistical profile accuracy and precision manufacturer for each of the classes was determined using Finally، the overall accuracy، the accuracy of the maps fuzzy and supervised classification was determined. Evaluating the accuracy of these two methods through determining the overall accuracy the results revealed that supervised method with an overall accuracy of 84. 91 and kappa value of 0. 7861 is more accurate than the fuzzy method with an overall accuracy of 83. 49 and kappa value of 0. 7667.