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Now showing items 1 - 15 of 15

  • Monitoring land cover changes in Isfahan Province, Iran using Landsat satellite data

    Soffianian, Alireza   Madanian, Maliheh  

    Changes in land cover and land use reveal the effects of natural and human processes on the Earth’s surface. These changes are predicted to exert the greatest environmental impacts in the upcoming decades. The purpose of the present study was to monitor land cover changes using Multispectral Scanner Sensor (MSS) and multitemporal Landsat Thematic Mapper (TM) data from the counties of Isfahan Province, Iran, during 1975, 1990, and 2010. The maximum likelihood supervised classification method was applied to map land cover. Postclassification change detection technique was also used to produce change images through cross-tabulation. Classification results were improved using ancillary data, visual interpretation, and local knowledge about the area. The overall accuracy of land cover change maps ranged from 88 to 90.6 %. Kappa coefficients associated with the classification were 0.81 for 1975, 0.84 for 1990, and 0.85 for 2010 images. This study monitored changes related to conversion of agricultural land to impervious surfaces, undeveloped land to agricultural land, agricultural land to impervious surfaces, and undeveloped land to impervious surfaces. The analyses of land cover changes during the study period revealed the significant development of impervious surfaces in counties of Isfahan Province as a result of population growth, traffic conditions, and industrialization. The image classification indicated that agricultural lands increased from 2520.96 km2 in 1975 to 4103.85 km2 in 2010. These land cover changes were evaluated in different counties of Isfahan Province.
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  • Monitoring land cover changes in Isfahan Province, Iran using Landsat satellite data.

    Soffianian, Alireza   Madanian, Maliheh  

    Changes in land cover and land use reveal the effects of natural and human processes on the Earth's surface. These changes are predicted to exert the greatest environmental impacts in the upcoming decades. The purpose of the present study was to monitor land cover changes using Multispectral Scanner Sensor (MSS) and multitemporal Landsat Thematic Mapper (TM) data from the counties of Isfahan Province, Iran, during 1975, 1990, and 2010. The maximum likelihood supervised classification method was applied to map land cover. Postclassification change detection technique was also used to produce change images through cross-tabulation. Classification results were improved using ancillary data, visual interpretation, and local knowledge about the area. The overall accuracy of land cover change maps ranged from 88 to 90.6%. Kappa coefficients associated with the classification were 0.81 for 1975, 0.84 for 1990, and 0.85 for 2010 images. This study monitored changes related to conversion of agricultural land to impervious surfaces, undeveloped land to agricultural land, agricultural land to impervious surfaces, and undeveloped land to impervious surfaces. The analyses of land cover changes during the study period revealed the significant development of impervious surfaces in counties of Isfahan Province as a result of population growth, traffic conditions, and industrialization. The image classification indicated that agricultural lands increased from 2520.96 km(2) in 1975 to 4103.85 km(2) in 2010. These land cover changes were evaluated in different counties of Isfahan Province.=20
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  • Monitoring vegetation cover changes using satellite data during 1972 to 2007

    Radari, Vahid   Soffianian, Alireza   Khajeddin, Seyed Jamalaldin   Najafabadi, Saedeh Meleki  

    One of the influential tools in the study field of pasture and vegetation cover science is technology of remote sensing and satellite data. Satellite data have essential role in preparing needed information for different vegetation aspects studying. One of the applications of satellite data is to prepare the vegetation cover percentage map. In this studying order to prepare the vegetation cover crown percentage maps of Mouteh wildlife refuge between 1972 and 2007, the satellite data were used. vegetation indices were produced using MSS sensors for 1972, TM for 1987, TM for 1998 and image of LISS III sensor for 2007. In this study cover crown percentage Map was provided by using indices which could decrease the soil reflectance. At first corrections was performed on each images. To make correlation between cover crown percentage and satellite data, 290 plot data with appropriate distribution across the region were collected. By using data and several image processing cover crown percentage was estimated for previous years. For each image cover crown percentage models were produced by simple linear regression between produced vegetation indices from each image and field data calculated. Regarding to data analysis SAVI plant index had the highest correlation with cover crown percentage and selected for producing vegetation crown cover percentage. using produced model from SAVI index vegetation crown cover percentage maps were produced in four classes percentage for each year. Results showed that cover crown percentage had decreasing trend in this period.
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  • Exploring structural and functional corridors for wild sheep (Ovis orientalis) in a semi-arid area

    Dehaghi, Iman Momeni   Soffianian, Alireza   Hemami, Mahmoud-Reza   Pourmanafi, Saeid   Salmanmahiny, Abdolrassoul   Wu, Gi-Mick  

    Although corridors have been the subject of extensive research in the recent years, the probable correlation between structural and functional corridors have not been addressed to date. To fill this scientific gap, we compared structural and functional corridors of wild sheep (Ovis orientalis) as a threatened species in a semi-arid area of central Iran. We first used Maximum-Entropy to develop wild sheep habitat suitability map. We then used Morphological-Spatial-Pattern-Analysis (MSPA) and circuit theory to map structural and functional corridors of wild sheep respectively. Bootstrapping techniques then were used to compare structural and functional corridors. We found that structural corridor is a concept which is dependent on the scale of observation. By changing edge-width from 600 to 1200 m, the total area of structural corridors increased by 63%. We also only found very small differences in the functional connectivity role of different MSPA categories (including structural corridors). All MSPA categories together accounted for only 20% of the functional connectivity. Although, in some cases functional corridors had a better performance in showing migration path of wild sheep between reserves, other cases showed that for effective conservation, both structural and functional corridors should be identified and considered in the planning step.
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  • Habitat suitability mapping for sand cat (Felis margarita) in Central Iran using remote sensing techniques

    Torabian, Shiva   Soffianian, Alireza   Fakheran, Sima   Asgarian, Ali   Feizabadi, Hossein Akbari   Senn, Josef  

    One of the primary reason of species extinction especially rare species with very specific requirements, is habitat destruction. To protect these species, habitat suitability evaluation plays a central role. Hence, an attempt is made in this study to evaluate the suitability of sand cat's habitat in a sand dune-dominated landscape in Iran. Four Landsat-derived indices including Normalized Difference Vegetation Index (NDVI), Weighted Difference Vegetation Index, Brightness Index (BI) and Salinity Index were combined to characterize sand cat's habitat requirements through a land use land cover (LULC) map. Furthermore, a set of landscape metrics were employed to explore the spatial pattern LULC classes. Sand cat's habitat suitability map was generated by linear combination of the standardized and relatively weighted NDVI and BI indices and then categorized into five classes of most suitable, highly suitable, moderately suitable, least suitable and not suitable. The results showed that about 75% of the total area is suitable for sand cat. Although this region is rich in biodiversity, it has not yet been subject to any conservation planning and should be granted more conservation attentions.
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  • ECOLOGICAL IMPACT ASSESSMENT OF ROAD NETWORKS AT LANDSCAPE SCALE USING SPATIAL ROAD DISTURBANCE INDEX (SPROADI)

    Nematollahi, Shekoufeh   Fakheran, Sima   Soffianian, Alireza  

    Development of roads can have deleterious effects on natural habitats containing species of conservation concern. Fragmentation of habitat into small, non-contiguous patches may result in dramatic population declinesThus appropriate studies quantifying ecological impacts of roads at landscape scale are essential. The main goal of this study was ecological impact assessment of roads network in Eastern part of Isfahan Province, including Abassabad wildlife refuge and Siahkouh National park, which are among the most important habitats for Asiatic Cheetah (Acinonyx jubatus venaticus) classified as Critically Endangered (CR) on the IUCN Red List. For this purpose, Spatial Road Disturbance Index (SPROADI), as a new landscape index was applied for the ecological impact assessment of the roads. This index uses three sub-indices including traffic intensity, vicinity impact and fragmentation grade to calculate the ecological impacts of road networks. Results obtained through quantifying the landscape Index (SPROADI) showed that the degree of disturbance by roads network is between 0 and 54.53. Our results also revealed that 12 percent of Abassabad wildlife and wide range of suitable habitats for Asiatic Cheetah were affected by roads, which presents a conservation concern for this critically endangered species.
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  • Analysis of multi-frequency and multi-polarization SAR data for wetland mapping in Hamoun-e-Hirmand wetland

    Baghdadi, Nicolas   Soffianian, Alireza   El Hajj, Mohammad   Rahdari, Vahid  

    The complex, dynamic and narrow boundaries between vegetation types make wetland mapping challenging. Hereafter the case study of the Hamoun-e-Hirmand wetland is considered by analysing eight Synthetic Aperture Radar (SAR) Images acquired in dry and wet periods with three wavelengths (X-band similar to 3 cm, C-band similar to 6 cm, and L-band similar to 25 cm), three polarizations (HH, VV and VH), and four incidence angles (22 degrees, 30 degrees, 34 degrees and 53 degrees). Then, the Support Vector Machine (SVM) classification method was applied to classify TerraSAR-X, Sentinel-1, and ALOS-PALSAR images. The final wetland land cover map was created by combining the classification results obtained from each sensor. In the case in question, results show that TerraSAR-X (X-band, HH-53 degrees) and Sentinel-1 data (C-band, W-34 degrees) were useful for determining the flooded vegetation area in the wet period. This is crucial for the conservation of water bird habitats since flooded vegetation is an ideal environment for the nesting and feeding of water birds. PALSAR data (L-band in both HH and VH polarizations, 30 degrees) were capable of separating the classes of vegetation density in the wetland. In the dry period, Sentinel-1 (VV and VH, 34 degrees) and TerraSAR-X (HH, 22 degrees and 53 degrees) had higher potential in land cover mapping than PALSAR (HH and VH, 30 degrees). Based on these results, Sentinel-1 in VV and VH provides the highest ability to discriminate between dry and green plants. TerraSAR-X is better for separating meadow and bare land. The results obtained in this paper can reduce the ambiguity in selecting satellite data for wetland studies. The results can also be used to produce more accurate data from satellite images and to facilitate wetland investigation, conservation and restoration.
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  • Geospatial modeling to identify the effects of anthropogenic processes on landscape pattern change and biodiversity

    Najafabadi, Saeideh Maleki   Soffianian, Alireza   Rahdari, Vahid   Amiri, Fazel   Pradhan, Biswajeet   Tabatabaei, Tayebh  

    This research used geospatial data to quantify biodiversity changes and landscape pattern change to track anthropogenic impacts of such changes at the Mouteh Wildlife Refuge (MWR), Isfahan, Iran. Satellite image duration of four decades, LandSat(1-5), and IRS-P6 data were used to develop land cover classification maps for 1971, 1987, 1998, and 2011. The number and size of land cover patches, the degree of naturalness, and the diversity indices were calculated and compared for a 40-year period. The results showed an increasing concern with regard to unplanned human activities. Some improvements of the natural landscape also occurred in the core protected zone of the study area. The number and size of land cover patches, the degree of naturalness, and the diversity indices were calculated. Overall changes in natural land use between 1971 and 1998 at MWR showed that the number of patches for natural land use has increased, but it also showed a decrease in 2011. Similar changes were observed for seminatural land use. Within the artificial classes, the number and area of patches were higher and the largest patch occurred in 2011. The maximum variation of diversity is related to the year 2011. The results showed an increasing concern with regard to unplanned human activities. Some improvements of the natural landscape also occurred in the core protected zone of the study area. Remote sensing and geographic information system offers an important means of detecting and analyzing temporal changes occurring in our landscape.
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  • Evaluating optimal sites for combined-cycle power plants using GIS:comparison of two aggregation methods in Iran

    Karimi, Hazhir   Soffianian, Alireza   Seifi, Sadri   Pourmanafi, Saeid   Ramin, Hadi  

    This study aims to use an integration of GIS and multi-criteria evaluation for combined-cycle power plant site selection and compares two aggregation methods for Iran. The information layers of the criteria are prepared in the GIS environment and then the layers standardised using fuzzy functions in IDRISI. All layers are combined using two conventional methods of fuzzy logic and weighted linear combination; from this information, the suitability maps were created. Results show that only 2.0% of the region under study is scored high-suitable using the fuzzy logic, while 21% of the area is considered as highly suitable when the weighted linear combination is used. Despite this significant difference, both approaches recommend the ideal place in the north and northwest of the study area. In conclusion, integrating GIS and multi-criteria evaluation is a comprehensive approach that improves and strengthens the suitability of site selection studies.
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  • Road-induced fragmentation and the environmental value of roadless areas in a partly protected landscape in Central Iran

    Mehdipour, Niloofar   Fakheran, Sima   Soffianian, Alireza   Pourmanafi, Saeid  

    This study assessed the effect of road development on vegetation fragmentation in and around a protected area network in western Isfahan Province, Central Iran. As the first study in Iran, an attempt was also made using the weighted linear combination-informed ecological value index of roadless area (EVIRA), to evaluate the environmental value of roadless areas based on a set of ecological and anthropogenic factors. Toward these aims, a Landsat 8-OLI image was processed to delineate land use/cover of the region. Road-induced fragmentation was then estimated by comparing the results of a small set of landscape metrics (DIVISION, SPLIT, MESH, LPI, and NP) measured from the original and road-included LULC map. The results showed road-induced increasing DIVISION (by 4.8-85.9%) and SPLIT (by 0.01-23.1%) and decreasing MESH (by 2.7-14%), LPI (by 1.3-32.4%), and NP (by 6-97.8%) values within all protected areas and across the entire study area, indicating a significant rise in landscape fragmentation and habitat loss. Roadless patch area and Thiessen connectivity stood out as the most salient criteria in determining environmentally valuable roadless areas. The results of EVIRA showed that the study region comprises some valuable but unprotected roadless areas which should be protected against road development or any kind of destructive human activities by laying out conservation plans or their inclusion to the current protected area network.
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  • Risk assessment of heavy metal soil pollution through principal components analysis and false color composition in Hamadan Province, Iran

    Soffianian, Alireza   Madani, Elham   Arabi, Mahnaz  

    In the process of decision making to combat heavy metals pollution, it is essential to have accurate quantitative information about heavy metals and their pollution hot-spots. The main purpose of this study was to determine spatial distribution of several elements (As, Sb, Cr, Cd, Ni, Co, Cu, Zn, Pb, Fe and V) on surface soils of Hamadan Province (Iran). It also sought to create a holistic view to determine the position, level, and anomaly of classified elements through principal components analysis (PCA), false color composition (FCC), inverse overlay method, and weighted linear combination. Finally, it tried to identify possible sources of pollution in the hotspots. Interpolation of heavy metal concentrations was performed using geostatistical methods and correlation analysis for locations. The most appropriate interpolation method was selected based on mean absolute error (MAE) and mean bias error (MBE) indices. According to Pearson’s correlation analysis, the elements were categorized in four groups (Fe, V, and Co; Cu, Ni, and Cr; Pb, Zn, and As; Sb and Cd). For Fe, Zn, As, and Pb, the best method was disjunctive kriging. For Co, Sb, Ni, and Cr, ordinary kriging was the most appropriate. Radial basic functions was also the best method for Cd and Cu. Overlaying of zoning maps of the elements and land use and geological layer maps showed that the distribution pattern of the studied elements did not fully conform to the existing land use pattern. Although the most influential factor on the concentration of elements in the studied soils was bedrocks, extensive use of chemical fertilizers should not be ignored. Moreover, urban pollution can also contribute to Pb contamination of soil.
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  • Determining Air Pollution Potential Using Geographic Information Systems and Multi-criteria Evaluation:A Case Study in Isfahan Province in Iran

    Karimi, Hazhir   Soffianian, Alireza   Mirghaffari, Nourollah   Soltani, Saeid  

    This paper presents a methodology of determining the air pollution potential based on pollutant source identification and meteorological parameters, using as a case study the Isfahan Province in Iran. First, taking the county as the evaluation unit, the regional air pollution information system database of Isfahan Province was established, supported by Geographic Information Systems. Then, the air pollution potential of the study area was assessed based on the analysis of regional air pollution, review of available literature, seeking advice from experts, and using determining factors such as population density, traffic, industries, wind speed, precipitation, temperature and humidity. A layer for each factor was prepared in GIS. After data acquisition, criteria were set and weighted by experts. Finally, all criteria were integrated using the Weighted Linear Combination method to obtain the spatial distribution of air pollution potential. The results showed that 55% of the total land area in Isfahan Province maintains a high to moderate level of air pollution potential resulting from unsuitable meteorological conditions along with high density of emissions from human activities. However, winds counteract the serious air pollution in some parts. The results suggest that very strict air quality management is needed in days of low wind speed, especially at places of increased air pollution resulting from human activities.
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  • Occurrence and depositional history of organochlorine pesticides in the sediments of the Zayandehrud River in the arid region of Central Iran

    Varnosfaderany, Mohammad Nemati   Soffianian, Alireza   Mirghaffari, Nourollah   Gu, Zhaoyan   Chu, Guoqiang  

    In this study, surface sediments along the Zayandehrud River (14 samples), and two dated core sediments (46 samples) from small artificial urban lakes at the middle section of the Zayandehrud River in the Gavkhooni basin in the central arid regions of Iran were analyzed for residual levels of 20 organochlorine pesticide (OCP) compounds. Total OCP concentrations ranged from 0.1 to 50.1 ng g-1 dry weight and from 1.9 to 51.5 ng g-1 dry weight in surface and core sediments, respectively. Dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD) were found to be the predominant OCPs in these sediments. The calculated metabolic and isomeric ratios confirmed the aged nature of residual dichlorodiphenyltrichloroethane (DDT) in sediments. Moreover, the isomeric ratios indicated the aged nature of technical HCH (hexachlorocyclohexane), while the contribution of gamma- HCH (lindane) as a main source has increased, especially in the last two decades. Past usage, as well as current usage of endosulfan technical mixture in the Gavkhooni basin, has been found in the last four decades. Analyses of sedimentary cores, as natural archives, have shown the successful ban on the use of organochlorine pesticides (especially DDT) in the Gavkhooni basin, and to some extent, in the central plateau of Iran. In general, it can be concluded that natural factors (i.e., floods and wet years) lead to soilleachate and play an essential role in remobilization and transfer of residual OCPs from soil to inland aquatic ecosystems in the Gavkhooni basin, which is an arid region. (C) 2020 Elsevier Ltd. All rights reserved.
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  • Investigation of landscape patterns of the Mouteh Wildlife Refuge using Geographic Information Systems

    Najafabadi, Saedeh Maleki   Soffianian, Alireza   Rahdari, Vahid  

    Landscape ecology as a modern interdisciplinary science offers new concepts, theories, and methods for land evaluation and management. One main part of landscape ecology is describing patterns in the landscape and interpreting the ecological effects of these patterns on flora, fauna, flow of energy and materials. Landscape studies require methods to identify and quantify spatial patterns of landscape. Quantification of spatial patterns is essential to understand landscape functions and processes. Landscape indices as diversity and naturalness can provide quantitative information about landscape pattern. Remote sensing and GIS techniques have high ability for landscape researchers to specify map and analyze landscape patterns. In this study the changes in a selected set of indices were investigated, in order to strengthen the management efforts of Mouteh wildlife refuge in Iran. Using different satellite analysis, Land use/land cover map were produced from satellite data and then the number and size of land cover patches, the degree of naturalness, and the diversity indices were calculated by GIS approaches and compared for a 35 years. The results showed an increasing concern with regards to unplanned human activities. Some improvements of the natural landscape also occurred in the core protected zone of the study area. To sum up, attention to conservation of natural landscape in this area is important in order to repair the natural conditions of habitats.
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  • Investigation of landscape patterns of the Mouteh Wildlife Refuge using geographic information systems

    Maleki Najafabadi, Saedeh   Soffianian, Alireza   Rahdari, Vahid  

    Landscape ecology as a modern interdisciplinary science offers new concepts; theories; and methods for land evaluation and management. One main part of landscape ecology is describing patterns in the landscape and interpreting the ecological effects of these patterns on flora; fauna; flow of energy and materials. Landscape studies require methods to identify and quantify spatial patterns of landscape. Quantification of spatial patterns is essential to understand landscape functions and processes. Landscape indices as diversity and naturalness can provide quantitative information about landscape pattern. Remote sensing and GIS techniques have high ability for landscape researchers to specify map and analyze landscape patterns. In this study the changes in a selected set of indices were investigated; in order to strengthen the management efforts of Mouteh wildlife refuge in Iran. Using different satellite analysis; Land use/ land cover map were produced from satellite data and then the number and size of land cover patches; the degree of naturalness; and the diversity indices were calculated by GIS approaches and compared for a 35 years. The results showed an increasing concern with regards to unplanned human activities. Some improvements of the natural landscape also occurred in the core protected zone of the study area. To sum up; attention to conservation of natural landscape in this area is important in order to repair the natural conditions of habitats.
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