جستجوی مقالات مرتبط با کلیدواژه "استان همدان" در نشریات گروه "محیط زیست"

Habitat fragmentation is the most important dynamic process that changes the habitat pattern in landscape. Today, the greatest threat to biodiversity worldwide is the destruction of parts of the habitat. The creation of corridors for communication between landscapes of fragmented lands for animal movement is emphasized that is important to prevent biodiversity loss. In this study, the Maxent methods was used to create a habitat suitability map and The least cost path analysis was used to identify and design the corridors. Eight habitat factors were selected based on studies, as well as behavioral and ecological characteristics of the species and study area, to investigate the impact of biological and non-biological variables on Armenian wild sheep habitat. Including slope, elevation, distance from main road, distance from wolf, distance from village, distance from water sources and aspect. According to MaxEnt analysis and the results of the Jack-Knife test 4 variables of distance from wolf, altitude, distance from village and distance from water sources have the most influence or role and direction variable has the least role. Finally, according to the surveys on the maps and field studies, three output routes were selected. The first route is not suitable because of the long distance and being in the middle of the village and having less height and being close to the main roads. The second and third paths are suitable because they eventually lead to one path and can be considered as the main corridor.

Every year a great deal of chemical fertilizers, pesticides and sewage sludge used in agriculture soils; this may cause the increase in concentration of Soil heavy metals. The purpose of this study was to investigate the effects of assessment of agriculture activities on accumulation of Cadmium, Cobalt and Chromium; and determines the trend of heavy metal accumulation in soil.

To achieve this purpose 97 soil samples were taken from different agriculture fields with different cultivation archaism in Hamedan province in western IRAN by systematic approach. ANOVA test has been used to compare the concentration of heavy metals in different farms, the trend of accumulation heavy metals obtained in regards to cultivation archaism and the mean of metals concentration in different cultivations. Moreover, contamination Factor Index has been used for comparison of contamination risk in cultivations with various archaisms.

Mean concentrations in 20-, 35- and 65-year-old cultures for cadmium metal were 0.14, 0.16 and 0.19, respectively, for cobalt metal, 17/94, 18/05 and 79/20, respectively and for chromium metal 58.89, 72.99 and 88.09 mg / kg, respectively. The results showed that the longevity of cultivation affected on heavy metal accumulation in soil. The trend of Cd, Co and Cr accumulation in soil was exponential.

Due to the fact that agricultural soils are one of the important routes for the transfer of heavy metals to the human food chain, it is necessary to monitor soils that are potentially exposed to toxic metals.

One of the environmental problems in recent years in the western regions of Iran is the activity of dust storms and aerosols in the atmosphere of cities. Malayer, Nahavand and Tuyserkan cities in the south of Hamedan province and west of Iran are vulnerable to the entry of dust storms. In this research, dust storms, aerosols and visibility status and the manner of entering these storms into the cities have been studied.
In this study, different statistical periods were studied for three cities during the years 1992 to 2010. Then, the Prevailing wind conditions, storms dispersion, and visibility reduction were studied throughout the year. Also, maps of pressure patterns on the days of the storm for synoptic analysis were prepared and evaluated.
Findings: The maximum annual dust incidence has occurred in Malayer in mid- spring (May), in Nahavand in the early spring (April) and mid-summer (August) and also in Tuyserkan at the end of spring (June).The highest and lowest number of dust storms occurred in Tuyserkan and Nahavand, respectively. Periodic changes of dust in the region have identified the rise of this climatic phenomenon in recent years. Dust frequency changes have shown a positive trend in the region with increasing height.The number of days with low visibility corresponded to the months of the occurrence of dust storms in the region and the most number of days with low visibility have been in June and July. Moreover, the synoptic analysis of the atmosphere shows that during the storm, an intense gradient of pressure and instability near the surface of the earth and the convergence flow at the level of 500 hPa have been created on the region.
Discussion and Counclusion: The results of this study indicate that the dust in the streets parallel with the Prevailing wind direction is easily transmitted to the central parts of the city. Then due to the collision of the dust stream with the city's high buildings, a part of the dust is transferred to the surface of the earth, and other part of the flow creates a torsion mode in the back section of the building. Eventually, another part of it passes through the city at altitudes above the buildings. Vegetation around the cities has reduced the flow of dust into the cities and is considered as a positive factor in reducing pollution in the region.

The extent of spread and source degradation would be determined using prediction of land use/ land cover changes. In this way these changes would be guided in the right directions. The aim of this study is modeling the process of land use / land cover changes of Hamedan province using Landsat TM satellite image of 1989 and IRS LISS III image of 2008.
After running the necessary corrections, land use/ land cover maps of the study area in the past two years were obtained using supervised classification with maximum likelihood algorithm. Then probability matrix of land use transition (to each other) were calculated using Markov chain with respect to land use/ land cover map. In the next step, Cellular Automata method was used to geo specified these changes.
Findings: Finally land use/ land cover map of Hamedan province for 19 years later (2024) was obtained and the area of each land use/ land cover was calculated.
Discussion and Counclusion: The results of this research shows that natural land use/ land covers will be decreased and transmited to human land uses in future. These changes are conceivable due to population growth and increasing human needs to exploit the nature; but this process should be considered to exploit the natural resources in a sustainable manner to avoid severe consequences in future.

Today there is competitions between countries for obtain more income from tourism industry. Gian Springhead is the most important and valuable Springhead in Hamedan Province. This region surrounded with Northern Zagros Forests belonging to world hot spots in Iran and Anatoly. The aim of this study was determination of Tourism Climate Index of Gian Springhead using GIS in 2012. For determination of suitable time for tourist visit the Gian Springhead we use the climatic data obtaining from the nearest synoptic and climatology stations of study area and prepared the zoning maps using ArcGIS 10. Results showed that because of TCI have a high value in September and December، therefore these month are suitable situations for tourist visit the Gian Springhead. In addition for achieve to sustainable development in the tourism industry، improve and development the tourism substructure recommended.

Today, modeling risk prediction as an effective strategy to protect the interests of human and wildlife populations is considered. The application of output maps such models to determinant the distribution range of conflicts; cost estimates and success of control programs are very beneficial. In the present study, we present a risk map for gray wolf (Canis lupus) attacks on human in Hamedan province. Thus, evaluation the performance of maximum entropy (MAXENT) modeling method to two methods presence/absence of artificial neural networks (ANN) and Support Vector Machine model (SVM). Based on predictions obtained north and center of the province are facing with high occurrence of wolf attacks. The results showed the important effective factors in distribution of wolf attacks are land use, human density and distance from the road. Between these factors, the land use was identified as the most important parameter. In addition, according to the results, the maximum entropy method, amount allocated area under the curve was greater (AUC =0.88) that indicates the high efficiency of this method in prediction of high risk areas in Hamedan province.