Majid Zaboli,; Akbar Fakhire; Ahmad ghanbari; Hamid reza Moradi; Alireza Rashaki
Volume 17, Issue 2 , September 2010, , Pages 317-330
Abstract
Growth of plants species in an area is affected by biological and environmental factors of that region. It is necessary to study some ecological requirements of species and also environmental characteristics of the study area in order to determine site potential and plant growth needs. this study performed ...
Read More
Growth of plants species in an area is affected by biological and environmental factors of that region. It is necessary to study some ecological requirements of species and also environmental characteristics of the study area in order to determine site potential and plant growth needs. this study performed to determine potential habitat of Haloxylon persicum and Haloxylon aphyllum in Sistan province by using Geographic Information System (GIS) technique. In this way sampling from habitats carried out for recognition of ecological requirements. Also thematic maps of area provided and digitized for attainment data layers which were needed. Then various sections of area were investigated and were compared with ecological requirements of these two species. Finally, the different layers of information were put together for every species. Base on our results, 3.18% and 3.52% of the studied area was suitable for growing H. persicum and H. aphyllum respectively. Assessment of accuracy of model was 93.3%.
Mohammad Khosroshahi; Mohammad taghi khashki; Tahereh Ensafi Moghaddam
Volume 16, Issue 1 , December 2009, , Pages 96-113
Abstract
Many climatology scientist adopted temperature and precipitation among all climatic parameters to identify desert regions from non-desert areas. There is no one definition of a desert that is accepted by all. The boundaries of a desert change radically depend on the variance in the range of proposed ...
Read More
Many climatology scientist adopted temperature and precipitation among all climatic parameters to identify desert regions from non-desert areas. There is no one definition of a desert that is accepted by all. The boundaries of a desert change radically depend on the variance in the range of proposed criteria definition accepted. Thus this study was carried out to identify the boundaries of a desert territory from non-desert regions using climatic data such as total precipitation, average intensity of daily precipitation, annual average temperature and evaporation together with the coefficient of variance and seasonal concentration. For each climatic factor a digital map was produced for all studied provinces using Geographical Information System (GIS). By overlaying all digitized climatic factors a transitional strip of boundary was recognized and then its accuracy was checked with field data and topographic map. Based on this boundary strip, three zones were recognized as 1- true desert zone located inside the strip of boundary.2- non-desert area, outside of the boundary and 3-Semi-true desert zone located in the boundary strip itself. It was concluded that true or natural desert that known as climatology desert are 700991 km2 or 42.5 % of the Iran map.
Ebrahim Farahani; Mohammad Khosroshahi; Majid Hosseni; Seyamak Loghmani
Volume 14, Issue 4 , February 2008, , Pages 490-499
Abstract
Vegitation cover is one of the important environmetal factors which can determine desert areas. In this article, we determine desert areas in Tehran province by GIS. In the study area, dominant plant types and some of main ecological properties of them were assigned. Finally, by available information ...
Read More
Vegitation cover is one of the important environmetal factors which can determine desert areas. In this article, we determine desert areas in Tehran province by GIS. In the study area, dominant plant types and some of main ecological properties of them were assigned. Finally, by available information and public characteristics of every plant type, desert area was separated. In this area, we distinguish 43 plant groups that 7 types of them belong to desert areas. This area is 307647 hectares which is formed 16.43 % of Tehran province.
Akbar Javadi; Hosein Arzani; Ali Salajeghe; Mahdi Farahpor; GHavam ... Zahedi
Volume 14, Issue 4 , February 2008, , Pages 513-523
Abstract
Proper use from water resources, especially in arid and semi arid rangeland are very important. Water is one of a valuable ecosystem component in rangeland management. In this study for surveying of water suitability, tree models including quality model, quantity and distance model made final model. ...
Read More
Proper use from water resources, especially in arid and semi arid rangeland are very important. Water is one of a valuable ecosystem component in rangeland management. In this study for surveying of water suitability, tree models including quality model, quantity and distance model made final model. FAO (1991) method (recommended for land capability evaluation) was used for suitability classification. The study was conducted in Halvan region is located in Yazd province. According to the results, water resources distance and accessibility to water is the most declining factor for suitability. Quality factor is a limiting factor in part of the study area, too. Based up on, areas more than 15km far from water point are not suitable, but less than 6km are very suitable. Proper distribution of water resources increases water suitability and cause better and monotonous utilization of rageland.
Kazem Dashtekian; Mojtabah Pakparvar; Jalal Abdollahi
Volume 15, Issue 2 , January 2008, , Pages 139-157
Abstract
Managing and monitoring of salinity is one of the most important affair in agriculture, specially in arid and semi arid area. For this purpose we have to use new technology like remote sensing and GIS. Most of scientist use maximum likelihood algorithm for mapping soil salinity, but in this method field ...
Read More
Managing and monitoring of salinity is one of the most important affair in agriculture, specially in arid and semi arid area. For this purpose we have to use new technology like remote sensing and GIS. Most of scientist use maximum likelihood algorithm for mapping soil salinity, but in this method field sampling is necessary. In this study several methods were used for producing soil salinity map. These methods are Brightness Index (BI), Normalized Difference Salinity Index (NDSI), Salinity Index (SI), Yazd Salinity Index (YSI), maximum likelihood and average of regression with some Bands. By analyzing and comparing methods with real soil salinity map, suitable method for this region were: 1. Average of regression with standardized band 1,2 and 3. 2. salinity index method.
Mohammad reza Najib zadeh; Adel Sepehri; Gholam ali Heshmati; Ali akbar Rasooli
Volume 15, Issue 2 , January 2008, , Pages 200-214
Abstract
Land degredation is a common phenomenon of arid rangelands. Improper utilization of rangelands out of their potential capability is the main cause of land destruction. To avoid damageing environmental resources, it is necessary to use lands based on their natural potentials. To have both sustainable ...
Read More
Land degredation is a common phenomenon of arid rangelands. Improper utilization of rangelands out of their potential capability is the main cause of land destruction. To avoid damageing environmental resources, it is necessary to use lands based on their natural potentials. To have both sustainable development and optimum utilization, we need to evaluate potential productivity of rangelands baesd on simple models that easly relate measurable environmental parameters to potential herbage productivity of rangelands. In this study our aim is to evaluate ERAMS model to evaluate land capability of Yekkeh Chenar Maraveh tappeh rangelands using GIS. This model includes 4 parameters including: slope, salinity, soil depth and rainfall. To get the final land capability map of the area, digital layers(maps) of those parameters were prepared and intered in the model using overlay functunality of GIS. Cross tabulation was used to asses the degree of agreement between the actual and potential land capability maps produced by ERAMS model. Kappa Index of Agreement value shows an overall agrement of 41% between the actual and potential land capability maps. That means ERAMS model was able to define the potential land capability of the area with 41% accuracy. Result also shows that the highest attained agreement belong to the category of high density vegetation. This model can predict the potential productivity of rangelands with high productivity rate better than those of low productivity as was the case for the study area.. This model is thus recommended to be used for vast and densly vegetatated areas.
Hamid reza Mir davoodi; Hojat.. Zahedi poor; Hamid reza Moradi; Gholam reza Godarzi
Volume 15, Issue 2 , January 2008, , Pages 242-255
Abstract
Improper management and unsuitable exploitation of land are the two most important problems of land resources utilization in the country. Unsuitable pattern of landuse together with sever landuse changes causes different environmental crisis including: environmental pollution and deterioration, expanding ...
Read More
Improper management and unsuitable exploitation of land are the two most important problems of land resources utilization in the country. Unsuitable pattern of landuse together with sever landuse changes causes different environmental crisis including: environmental pollution and deterioration, expanding desertification, soil erosion, natural resources depletion, reduction of biological diversity and reduction the potential of land capability. These problems significantly influence the production resources of recent and future generation and prevent sustainable development of the country. In this research, ecological land capability of Markazi Province that is the most important part of the procedure of landuse planning were determined with preparing ecological resources maps such as topography with scale of 1/25000, geology, soil, climate and related parameters, vegetation cover, faults, water resources and etc. Slop, aspect and height class maps also were established based on Digital elevation model of the area and integrated together to form landform map of the Province. Environmental units with base 1, 2 and 3 also were established with overlaying land form, soil and vegetation maps. Ecological land capability of agricultural and rangeland were put in 7 classes. The results show that from total 2921364.6h area of Markazi Province, 15000 ecological units could be determined of which 121689.5h or %4.16 were in class of 1, 191634.77 h or %6 in class of 2, 615791.5 h or %21.07 in class of 3, 569834.8 h or %19 in class of 4, 1170699.6h or %40 in class of 5, 188381.18 h or %6.44 in class of 6 and 63333.2 h or %2.16 in class of 7 of agriculture and rangeland ecological capabilities.
Kian Najafi Shabankareh; Mohammad Khosroshahi; Mohammad Gholampoor
Volume 15, Issue 1 , January 2008, , Pages 95-113
Abstract
Resistant species to salinity and aridity and temperature fluctuation are approximately introducer of desert. These species have particular morphology compatibling themselves to fragile and acute condition of desert area. Some species accumulate water in their tissues. Some other species decrease leaves ...
Read More
Resistant species to salinity and aridity and temperature fluctuation are approximately introducer of desert. These species have particular morphology compatibling themselves to fragile and acute condition of desert area. Some species accumulate water in their tissues. Some other species decrease leaves area and develope their root systems to use groundwater resources and some have particular phytocynthesis systems. As a general desert species with different mechanism resist against acut climate condition and unsuitable soil properties of desert regions. Characteristics of desert species distribution area can be determined the geographical domain of desert area. In this study dominant plant types in certain grupes and some of main ecological properties were assigned and related map in GIS environment was prepared. Finally, according to public characteristics of dominant species of every plant type and accompany species, desert area was sperated. In study area 22 plant group, each consist of some plant types was recognized. The distribution area of plant groups of Zygophyllum atripolicoides, Gymnocarpos decander and Hammada salicornica is about 730132, 599941 and 53260 hectar respectively.
Mohammad Ggeitury; Naser Ansari; Abbas ali Sanadgool; Mosayeb Heshmati
Volume 13, Issue 4 , February 2007, , Pages 314-323
Abstract
There are various factors that cause cantinous changes in the quality and quantity of natural resources which result in poor ranching, destructive flood, migration of villagers and nomads to large nearby cities and poverty of rural people. Identification of factors which are ...
Read More
There are various factors that cause cantinous changes in the quality and quantity of natural resources which result in poor ranching, destructive flood, migration of villagers and nomads to large nearby cities and poverty of rural people. Identification of factors which are destructive to rangelands in Kermanshah Province was carried out to prevent destruction, to achieve optimal management and recognize priorities in planning. First of all, information and statistics concerning vegetation map and base map ( from past to present ) were obtained and analyzed. On the basis of Pabo Map and GIS, four different climatic regions of dry forest, warm semie-steppe. Cold semi-steppe and high mountainous were distinguished for Kermanshah Province. According to the survey conducted to explore the ecology of Kermanshah, index regions were identified using Pabo climatic Map. In any region, the vegetation of the range along with index of destruction of vegetation was studied. next step, questionnaires related to destructive factors to vegetation were filled by both experts and rural families and nomads and, then were assessed using the statistic method of regression and finally the frequency of different destructive factors to rangelands was calculated. The results indicated that in Kermanshah rangelands, changing the land use, the increase in the number of animals, and early grazing are the common factors of destruction respectively
Morteza Akbari; Hamid reza Karim zadeh; Reza Modares; Bahareh Chakoshi
Volume 14, Issue 2 , January 2007, , Pages 124-142
Abstract
Desertification is the ecologic and biologic reduction which may occur naturally or non naturally. Desertification process usually effects arid and semi arid region and reduce the land efficiency very rapidly. This study has been conducted to evaluate and classify desertification with the aim of geographic ...
Read More
Desertification is the ecologic and biologic reduction which may occur naturally or non naturally. Desertification process usually effects arid and semi arid region and reduce the land efficiency very rapidly. This study has been conducted to evaluate and classify desertification with the aim of geographic information system and remote sensing techniques. In this study, TM data of 25 shahriver 1369(16 October 1990) and ETM+ data of 16 shahrivar 1380 (7 October 2001) were used. Geometric, radiometric and sun height angle correction were carried out on the images. Supervised and unsupervised classification were used for both two images and 9 land uses were classified and compare quantitatively due to geomorphology and desertification attributes. Each main and partial desertification factor was input to geographic information database and scaled to make the map of desertification severity based on recommended method for Iran and FAO map of desertification vulnerability. The result of desertification severity which shows desertification condition, velocity and potentiality, showed that natural desertification occurs in 35 % of area with different medium, high and very high desertification severity. Anthropogenic desertification includes 65 % of study area with high and very high condition. But in desertification vulnerability map, very high desertification vulnerability was determined in 20 % of area with simultaneous human and animal effect and high desertification vulnerability was determined on 80 % area with only animal effect. According to the map, for arid region of north of isfahan, it was identified that range land use change to agriculture, improve agricultural patterns, over grazing, incident economic condition and ground water over exploitation are the most important anthropogenic factor, and drought and soil and water salinity are the most important natural factors. Desertification trend is enhancing to north west of the study area which will make trouble for rangelands, residential and industrial areas.
Abolghasem Dadrasi Sabzavari; Mojtaba Pakparvar
Volume 14, Issue 1 , January 2007, , Pages 33-52
Abstract
Desertification is one of the most difficult issues which has been taken into consideration in the world. The main objective of this study is determination of lands affected by desertification using remote sensing and geographic information systems, in Sabzevar. To meet the objective, Satellite ...
Read More
Desertification is one of the most difficult issues which has been taken into consideration in the world. The main objective of this study is determination of lands affected by desertification using remote sensing and geographic information systems, in Sabzevar. To meet the objective, Satellite imagery of Landsat TM- 29 April 1987 and 13 May 2001 were selected and used, after haze and geometric correction. Principal Components (PC) and False Color Composit (FCC) were calculated, finally FCC521: RGB was selected for background of classification because of the best correlation. The Satellite images were classified by the maximum likelihood algorithm on the basis of field data. A study was conducted to determine the iso line of change in groundwater salinity and depth, in the study area, by using subsurface water data ( quality and quantity). The results show that on non saline parts and in the area of gypsum, the changes are negligible. The area of land uses are more or less the same except in agriculture which the land has increased by 3632 ha and in urban area which developed 672 ha. Merging and processing the whole data shows that the agriculture lands increased from 1987 to 2001. More salinity and less depth of groundwater are the results of groundwater data analysis, specially in south east part of the region
Ebrahim khalifeh; Mohammad reza Kavianpoor; Mojtabah Pakparvar; Sajad Vafaei
Volume 14, Issue 2 , January 2007, , Pages 204-221
Abstract
Wind erosion is one of the major problems in arid and semiarid regions, where the erosion and sand transport caused by wind can lead to serious problems for civilians live in those areas. The regions under wind erosion, includes the sources, transition and deposition areas. Amongst them, identification ...
Read More
Wind erosion is one of the major problems in arid and semiarid regions, where the erosion and sand transport caused by wind can lead to serious problems for civilians live in those areas. The regions under wind erosion, includes the sources, transition and deposition areas. Amongst them, identification of the sources areas is significantly important, which affects our investigations, evaluation and control over wind erosion. It has been found that the application of Remote Sensing (RS) techniques and Geographical Information Systems (GIS) is considerably useful to find the sources of sand in wind erosion. In this study, a combination method based on Image Processing and Wind Analysis (IPWA) has been introduced and used to identify the sources of deposited sand in areas under wind erosion. The method is based on utilizing and composing of image processing techniques such as image enhancement, threshold, false color composition, filtering, and Spectral Profile Testing and Analysis. The results are compared with other investigations to validate the method. It was observed that the results of the present method are well comparable with those of previous researches which are highly based on field investigations. Without extensive field measurements, the method reduces the time and the cost of investigation and provides a basis for repeating the operation at any time and everywhere, which is required.
Abalfazl Akbarpour; Mohammad bagher Sharifi; Hadi Memarian Khalilabad
Volume 13, Issue 1 , February 2006, , Pages 27-38
Abstract
Land cover information can be used in hydrologic modeling to estimate the value of surface roughness or friction. The objective of this work is comparison of two different methods to provide land cover maps using Landsat images to estimate surface roughness in the manning equation and curve number (CN) ...
Read More
Land cover information can be used in hydrologic modeling to estimate the value of surface roughness or friction. The objective of this work is comparison of two different methods to provide land cover maps using Landsat images to estimate surface roughness in the manning equation and curve number (CN) in SCS method in the Kameh watershed located in the North of Torbat Heydarieh. At the first, Radiometric and Geometric correction performed on ETM+ data. Then with field surveying, The land cover classes were defined and training areas were selected. All of the bands with the exception of band 6 were used in classification. Because of low accuracy of village and road classes, These classes were removed from classification process and for entering these classes in the final map, information from the other layers of GIS system were applied. Results of this work show that in the fuzzy method using 3 layers in classification, The overall accuracy is 75.12% and kappa Index is 0.63. While those of fuzzy method using 2 layers in classification and maximum likelihood method are (73.3%, 0.6) and (72.39%, 0.59) respectively. Therefore the fuzzy method using 3 layers in classification is recommended
Davod Lotfollahzadeh; Ali Khalkhali
Volume 9, Issue 3 , September 2001, , Pages 959-974