Ommolbanin Kazemi Gordgi; Hasan Ahmadi; Mohammad Jafari
Abstract
The ultimate aim of any research on the mass movement processes is to prepare zonation map and classify area into different degrees of hazard in order to mitigating related damages. This study was undertaken using F-AHP & GIS within Nekaroud watershed in Mazandaran province. Pairwise comparisons ...
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The ultimate aim of any research on the mass movement processes is to prepare zonation map and classify area into different degrees of hazard in order to mitigating related damages. This study was undertaken using F-AHP & GIS within Nekaroud watershed in Mazandaran province. Pairwise comparisons showed that sub-criteria’s Slope (>30%), elevation (> 1700 m), distance from fault (0-200 meter), distance from river, residual land-use and precipitation (>600 mm) have high weight than others in their group which lead to increasing occurrence of landslides. In the study area much amount of lime stone was found which is effective in reducing landslide. Major parts of central areas of watershed are prone to the most dangerous and high frequency landslides, other parts of watershed classified into medium and a little part is in low danger class.
M. Ghorbani; H. Azarnivand; A.A Mehrabi; S. Bastani; M Jafari; H. Nayebi
Abstract
Since last decades, there has been a growing interest in the human/social dimensions of natural resources governance especially the structure of social networks in achieving to successful co-management of natural resources. Network analysis as a suitable tool in optimum planning of the “network ...
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Since last decades, there has been a growing interest in the human/social dimensions of natural resources governance especially the structure of social networks in achieving to successful co-management of natural resources. Network analysis as a suitable tool in optimum planning of the “network management” of rangeland in regional scale, can improve inter-organizational decision-making and coordination among key actors. Trust development and mutual relations among various actors is a key factor in policy of rangeland co-management issue. In this study, trust and collaboration networks between informal and formal institutions and rangeland users in co-management process have been investigated. Social network analysis as a quantitative method has been implicated in this research. The results of this study indicate that “Veterinary Office of Taleghan” and “Village Council” can play a key role in policy and planning of rangeland co-management which is related to higher density of trust and collaboration ties. Moreover, trust and collaboration networks among the Veterinary Office and rangeland users have more sustainability than these in related to other institutions. However, the sustainability of networks among all of institutions and rangeland users has low level. Statistical results show there is a high correlation (70%) between trust and collaboration networks and also 50% of collaboration changes are related to trust factor. Also, it can be state that lack of trust and collaboration between the Natural Resources Office and rangeland users is a key challenge for initiating of rangeland co-management. Finally, social network analysis helps manager and planner in detecting of the challenges of rangeland co-management and policy in tune with solving these challenges.
Mohammad Ali Zare Chahouki; Masoud Yousefi; Mohammad Jafari; Hossein Azarnivand; Marjan Shafizadeh Nasrabadi
Abstract
The current research was carried out to find out the most effective environmental factors in plant species occurrence by classification and ordination methods. For this purpose, the study was conducted in Nir rangelands of Yazd province and topography, climate, soil and grazing intensity data of the ...
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The current research was carried out to find out the most effective environmental factors in plant species occurrence by classification and ordination methods. For this purpose, the study was conducted in Nir rangelands of Yazd province and topography, climate, soil and grazing intensity data of the region were determined. Sampling method was randomized–systematic and within each sampling unit 3-5 parallel transects with 300-500 m length, each containing 30-50 quadrates (according to vegetation variations) were established. Quadrate size was determined for each vegetation type using the minimal area; hence suitable quadrate size for different species was determined 1*2m–10*10m (2-100 m2). Soil samples were taken from 0-30 and 30-80 cm in starting and ending points of each transect. Measured soil properties included gravel, texture, available moisture, saturation moisture, organic matter, lime, gypsum, pH and electrical conductivity. To analyze environmental data, classification (using TWINSPAN) and ordination (using PCA, CCA) were used. The results indicated that soil salinity, texture and available water play the main role in distribution of plant species.
M Jafari; H Azarnivand; A Hajibaglo; E Alizadeh
Volume 63, Issue 3 , December 2010, , Pages 307-318
Abstract
This study investigates the relationship between litter quality and aerial parts of plant on C, N, K, P and C/N ratio of soil in four rangeland species including Agropyron intermedium, Bromus tomentellus, Eurotia ceratoides and kochia prostrata. After recognizing the sites of these species in Hamand ...
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This study investigates the relationship between litter quality and aerial parts of plant on C, N, K, P and C/N ratio of soil in four rangeland species including Agropyron intermedium, Bromus tomentellus, Eurotia ceratoides and kochia prostrata. After recognizing the sites of these species in Hamand Absard located in 65 km of northern Tehran, at the end of growing season, samples of litter, aerial part of plants and soil were taken using systematic- random method. For this purpose, five transects, each of l00 m length and 50 m spacing were taken. Two plots in each transect with an area of 1 m2 were established. In each plot, soil samples under plants and without plant area (control samples) at depth of 0-30 cm were taken. The C, N, P, K, EC, pH and texture of samples were analyzed in laboratory. Analysis of variance, Dunnett's test and t-student test were applied to the data. Results show that in the aerial part of plant, C and C/N ratio of Agropyron intermedium and P, K and N of Kochia prostrata are higher than other species. In case of litter, C, K and C/N of Eurotia ceratoides and N and P of Kochia prostrata showed higher values. However the results of soil samples show that C of Agropyron intermedium, N and C/N of Kochia prostrata and K of Bromus tomentellus are higher than other species. Totally, Kochia prostrata showed the best litter quality, decomposition rate and effects on soil.
mohsen Naghiloo; mohamad Jafari; mohamad Tahmoures; asghar Kohandel; farinaz Hamedanian
Volume 63, Issue 1 , June 2010, , Pages 119-11
Abstract
The purpose of this research was to investigate the relationship between vegetation cover and soil characteristics in order to determine the most important soil factors which affect on quantitative variations and types of vegetation cover in the study area. The study area is located in west of Tehran ...
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The purpose of this research was to investigate the relationship between vegetation cover and soil characteristics in order to determine the most important soil factors which affect on quantitative variations and types of vegetation cover in the study area. The study area is located in west of Tehran province and southeast of Hashtgerd, next to Najm-abad village. After field studies, the index vegetation types were selected and randomized-systematic sampling method was used for soil and vegetation cover sampling in each key area. The area of each plot was determined according to type of plant species and their distribution using minimum area method. Some vegetation cover parameters such as canopy cover percentage, density and frequency of plant species were measured in the area. Then soil sampling were done from 2 horizons including 0-10 cm and 10-30 cm in each plot and soil attributes such as texture, pH, organic carbon percentage and gypsum were measured in the laboratory. Afterwards, statistical methods like multivariate regression, analysis of variance and RDA technique were used for analyzing soil and vegetation cover data. The results showed no specific difference between soil and vegetation data except for gypsum. In other word the effective factor on vegetation cover variation was soil gypsum.
M. Jafari; A. Tavili; M. Rostampour; M. A. Zare Chahouki; J. Farzadmehr
Volume 62, Issue 2 , October 2009, , Pages 197-211
Abstract
This study was carried out to investigate the effective environmental factors in the distribution of vegetation in Zirkouh rangelands of Qaen. After delimitation of the study area, sampling of soil and vegetation were performed using randomized- systematic method. Vegetation cover was recorded by using ...
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This study was carried out to investigate the effective environmental factors in the distribution of vegetation in Zirkouh rangelands of Qaen. After delimitation of the study area, sampling of soil and vegetation were performed using randomized- systematic method. Vegetation cover was recorded by using Braun-Blanquet combined abundance-cover scale in each sample. Within each sample, one profile was dug and soil samples being taken at 0-20 cm and 20-100 cm depths. Physical-chemical characteristics were determined include texture, lime, organic matter, soil moisture content, saturation moisture, EC and pH. Five vegetation groups were identified after the application of TWINSPAN method and were named after the characterizing species as follows: Salsola richteri-Aelorupes littoralis; Zygophyllum eurypterum-Haloxylon ammodendron; Artemisia sieberi-Zygophyllum eurypterum; Ammodendron persicum-Stipagrostis pennata; Artemisia aucheri-Amygdalus scoparia. The results of PCA showed that environmental factors best related with the distribution of this vegetation are texture, lime, organic matter, soil moisture content, saturation moisture, elevation and slope.
M Jafari; M Tahmoures; M. Naghiloo
Volume 62, Issue 1 , June 2009
Abstract
The use of GIS tools is one of the newest methods for performance of different land evaluation and planning projects. This research with the purpose of determination of appropriate landuse to natural land potential and improvement of land management of catchments was executed using GIS-tools in Taleghan ...
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The use of GIS tools is one of the newest methods for performance of different land evaluation and planning projects. This research with the purpose of determination of appropriate landuse to natural land potential and improvement of land management of catchments was executed using GIS-tools in Taleghan area. At first ecological and socio-economic resources determined, mapped and entered to GIS environment. Then by analysis of more than 15 information layers, homogeneous and ecological units determined. By the use of watershed management and combined land planning model and in accordance with natural and socio-economic characteristics of the watershed, suitable landuses were proposed. At last optimum landuse map and the existing state of landuse map were adapted in GIS space. The results showed that 17 percent of the watershed area has suitable landuses while 83 percent of the watershed area needs landuse change.