Ali Mirhosseini; Younes Asri; Mohammad Abolghasemi
Volume 27, Issue 2 , June 2020, , Pages 192-203
Abstract
The Bahadoran Kalmand protected area with an area of 255000 hectares is located at about 30 km Yazd township and in the southeastern township of Mehriz with geographical coordinates of 31° 00¢ to 31° 40¢ North latitude and 54° 15¢ to 55° 20¢ East longitude. The ...
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The Bahadoran Kalmand protected area with an area of 255000 hectares is located at about 30 km Yazd township and in the southeastern township of Mehriz with geographical coordinates of 31° 00¢ to 31° 40¢ North latitude and 54° 15¢ to 55° 20¢ East longitude. The vegetation cover was studied using the physiognomic-floristic method. Some soil characteristics were evaluated based on conventional methods and data were analyzed by Principal Component Analysis (PCA) method. The results showed that there was a special relationship between different plant communities and soil characteristics. The most important factors in separating these plant communities were electrical conductivity, acidity, texture, organic carbon, and sodium adsorption ratio. In general, in regard to habitat conditions, each plant community has different ecological needs and tolerance range with environmental factors and soil characteristics.
Asad Sadeghpour; Javad Moetamedi; Esmaeil Sheidai Karkaj
Volume 26, Issue 4 , December 2019, , Pages 838-854
Abstract
Information of plant diversity and its relationship with environmental factors are necessary requirements for rangeland rehabilitation techniques and priority of biodiversity conservation in local habitats. To collect vegetation cover data, the Namin mountainous rangelands were selected and systematic ...
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Information of plant diversity and its relationship with environmental factors are necessary requirements for rangeland rehabilitation techniques and priority of biodiversity conservation in local habitats. To collect vegetation cover data, the Namin mountainous rangelands were selected and systematic random sampling in ecological units was used. The relationship between plant diversity and ecological unit’s characteristics (Sub-basins) was studied by recording the data in physiographic, topographic, chemistry and physics in the soil. To investigate the relationship between species diversity and environmental factors, the redundancy analysis (RDA) method was used as linear method based on gradient length. Based on the results, the physiographic and topographic had significant effect on the richness of the species. On the other hand, soil chemical properties had the greatest impact on the amount of species evenness and diversity of the ecological units and explained 89.64% of the variations. In general, slope, organic carbon amd EC are the most important effective characteristic on the enhancement species diversity idexes and the length parameters. It was also indicated that area and direction of sites are the most important factors on reduction of diversity indices. Therefore, in situations where the purpose of the management to be improve species diversity, places where are in endanger in terms of chemical properties of the soil (organic matter and, consequently, organic carbon) should be prioritized. If the aim of management to be increase in vegetation structure and percentage of plant protection from splash erosion, in this case, places where are in the southern direction and have a steep slope should be prioritized. Furthermore, rangeland rehabilitation techniques are a priority in larger-scale units due to the lower species richness, and smaller units, due to the high plant species richness, should be prioritized of conservation and protection.
Farzad Ahmadi; Ghodratollah Heydari; Ronak Ahmadi
Volume 26, Issue 2 , July 2019, , Pages 412-422
Abstract
The aim of this study was to investigate the factors affecting the beneficiaries' economic recession in the BolbanAbad Rangelands. The statistical population of this study was 400 beneficiaries in the BolbanAbad Rangelands. The sample size of this study was determined to be 196 ...
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The aim of this study was to investigate the factors affecting the beneficiaries' economic recession in the BolbanAbad Rangelands. The statistical population of this study was 400 beneficiaries in the BolbanAbad Rangelands. The sample size of this study was determined to be 196 rangeland beneficiaries by using Krejcie and Morgan table. A random sampling method was used to select the samples. The tool used to collect data and information was a questionnaire. The validity of the questionnaire was confirmed by rangeland experts and its reliability was confirmed by Cronbach's alpha coefficient. Data were analyzed by SPSS software version 22. The results of Spearman correlation test showed that economic factors had the highest correlation with the beneficiaries' economic recession. In addition, the results of factor analysis showed that among the economic factors, the lack of job diversification with a coefficient of 0.912; among the management factors, the limitation of credit transfer to low-income beneficiaries to reduce the income dependency with a coefficient of 0.885; among the environmental factors, the traditional livestock vulnerability due to drought and forage deficiency with a coefficient of 0.893; and among the social factors, the distrust between the beneficiaries in collaborative activities with a coefficient of 0.910 had the most impact on the beneficiaries' economic recession. Also, the results of the path analysis showed that the most direct and total effects were related to economic factors and the most indirect effect was related to management factors.
Jalil Farzadmehr; Hamed Sangooni; Hamid Rouhani
Volume 26, Issue 1 , June 2019, , Pages 18-28
Abstract
In order to investigate the relationship between the distribution of plant communities and environmental factors in Bidokht area, a physiognomic-floristic approach was used. The appropriate area of sampling plot and sample size were determined by the minimal area method and statistical ...
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In order to investigate the relationship between the distribution of plant communities and environmental factors in Bidokht area, a physiognomic-floristic approach was used. The appropriate area of sampling plot and sample size were determined by the minimal area method and statistical approach, respectively. In each plot, the number of plant species and their canopy cover were determined and vegetation mapping was conducted. In each of the plant communities, six soil profiles were drilled and soil samples (composite) were taken from 0 to 100 cm depth. After transferring to the laboratory, parameters of soil texture, lime, pH, electrical conductivity, organic matter, sulfate, calcium, phosphorus, potassium and nitrogen were measured. Information layers were also provided for altitude, slope and aspect of the study area. In order to determine the factors influencing vegetation distribution, PCA-ORD software was used to analyze the principal components (PCA). The results showed that there was a relationship between the factors studied and distribution of vegetation (four rangeland types). The results of principal component analysis showed that the most important environmental characteristics affecting distribution of plant communities in the region were clay, sand, organic matter, electrical conductivity, and potassium (PCA first axis).
Amir Mirzaie Moousavand; Ardavan Ghorbani; Mohammad Ali Zare Chahooki; Farshad Keivan B ehjoo; kiomars Sefidi
Volume 25, Issue 2 , August 2018, , Pages 235-247
Abstract
The aim of this study was to investigate the effect of environmental factors on Prangos ferulacea Lindl. and P. pabularia Lindl. distribution in the rangelands of Ardabil province. Seven habitats of Prangos genus were identified, so that P. ferulacea was distributed in three ...
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The aim of this study was to investigate the effect of environmental factors on Prangos ferulacea Lindl. and P. pabularia Lindl. distribution in the rangelands of Ardabil province. Seven habitats of Prangos genus were identified, so that P. ferulacea was distributed in three habitats and P. papularia in two habitats. In each habitat, sampling sites were identified and in each site three transects of 100m were established, and the density of the study species were recorded in ten plots of 4m2. Soil samples were taken from the depth of 0 to 30 cm at the start, middle and end of each transect. In the vicinity of each habitat, sampling was done in the same way. In sampling plots, elevation, slope, aspect, and soil characteristics such as organic matter, N, P, K, pH, EC, and texture were measured. To investigate the effects of environmental factors on the presence or absence of the study species and to compare the characteristics of the variables measured one-way ANOVA and Tukey test were used.Discriminant analysis was used to determine the degree of importance of the environmental variables measured in the distribution of the study species. Results showed that P. pabularia was distributed in the habitats with the high content of P, clay, EC, rainfall, sand, slope and pH; while P. ferulacea was distributed where the elevation was high but rainfall and the content of K were low. According to the results of discriminant analysis, variables such as EC, organic matter, K, elevation, slope, aspect, silt, clay, rainfall, and temperature were effective in discrimination of sites and species distribution. The results of the present study could be useful to propose the species for range management, improvement and reclamation.
Amir Mirzaie Mousivand; Ardavan Ghorbani; Mohammad ali Zare Chahooki; Farshad Keyvan Behjoo; Kiomars Sefidi
Volume 24, Issue 4 , January 2018, , Pages 791-804
Abstract
The aim of this study was to investigate the effects of environmental factors on distribution of Prangos uloptera in rangelands of Ardabil province. The habitats of Prangos were identified and the habitats, in which the study species was present, were selected. Sampling was also carried out in the vicinity ...
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The aim of this study was to investigate the effects of environmental factors on distribution of Prangos uloptera in rangelands of Ardabil province. The habitats of Prangos were identified and the habitats, in which the study species was present, were selected. Sampling was also carried out in the vicinity of each habitat where the study species was not present. Three transects of 100-m length were established, on which canopy cover percentage and density of species were measured within 10 plots of 4m2. Soil samples were taken from the beginning, middle and end of each transect. In sampling places, altitude, slope, aspect, and soil characteristics were measured. Independent t test and cluster analysis were applied to comparison and classification of presence and non-presence areas and determination function was applied to determine the importance of factors affecting the presence of this species. The results of t test showed that there were significant differences between all variables except for temperature and precipitation. According to the results of cluster analysis, the studied species had more distribution in places with high altitude and steep slopes, high organic matter, and high nitrogen and sand. The results clearly showed that climatic parameters including precipitation and temperature as awell as altitude and sand percentage in the first grade and then aspect and soil characteristics including nitrogen and phosphorus in the second grade were the most important factors affecting the distribution of study species. According to the results, better decisions could be taken to use this species for range management, improvement and reclamation.
shahla Ghaderi; Alireza Amirian Chekan; Amaneh Karim Zadeh; Masoume Difrakhsh; Javad Pourrezaie
Volume 24, Issue 3 , October 2017, , Pages 478-493
ali goharnejad; pejman tahmasebi; esmael asadi; javad motamedi
Volume 24, Issue 1 , May 2017, , Pages 1-15
Abstract
In contrast to the taxonomic biodiversity, based only on the relative abundance of species in the community, functional diversity summarizes various aspects of the biological composition and, hence, the role of populations in the community. Functional diversity may be linked directly to the ecosystem ...
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In contrast to the taxonomic biodiversity, based only on the relative abundance of species in the community, functional diversity summarizes various aspects of the biological composition and, hence, the role of populations in the community. Functional diversity may be linked directly to the ecosystem services; the plant biomass encompasses many ecosystem services such as food supply, conservation, tourism, and pollination. In this study, we tested several hypotheses (1) existence of a close relationship between species richness and plant biomass (2) existence of a close relationship between FAD2 (Functional Diversity index) and plant biomass (3) explaining the high percentage of plant biomass variations. The results showed that the species richness in order to predict the plant biomass with a correlation coefficient equal to three does not count as a proper indicator. However, the correlation coefficient of FAD2 Functional Diversity with plant biomass was about 0.4, which is relatively good indicator to estimate the plant biomass because of explaining a significant percentage of the biomass variations. Finally, our results clearly showed that the incorporation of abiotic factors, plant traits and functional diversity (FAD2), containing the parameters of rainfall, leaf length, plant height and FAD2 index, could explain 75% of plant biomass variations and was considered as the most appropriate model predicts plant biomass.
Setareh Babaee; Hamid Niknahad; Bakhtiar Fatahi; Mousa Akbarlou
Volume 23, Issue 3 , January 2017, , Pages 473-486
Abstract
The purpose of present study was to investigate the relationship between density, cover percentage, and biomass of Daphne mucronata and the most important environmental factors including soil physicochemical properties and topographic characteristics. For this purpose, in three areas (area with high, ...
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The purpose of present study was to investigate the relationship between density, cover percentage, and biomass of Daphne mucronata and the most important environmental factors including soil physicochemical properties and topographic characteristics. For this purpose, in three areas (area with high, medium and low coverage of Daphne mucronata), four transects of 100 m length were located on the slope. Density with the Point- Centered Quarter Method; coverage percentage through linear transect method and biomass via cutting and weighing method were estimated. Soil samples were systematically taken along each transect at the depth of 0-10cm and 10-30 cm in each area. Once in the laboratory, some soil physical and chemical properties such as soil texture, pH, EC, percentage of organic matter, and total nitrogen were measured. The relationships between plant measurements of Daphne mucronata and soil properties and topographic characteristics were investigated using multiple regression analysis. The results demonstrated that along topographic characteristics, the slope of 60-70% and the height of 1850 to 2050m had the most influence on the density and cover percentage of Daphne mucronata, likewise the slope of 80-90% and the height of 2050 to 2350m had the most influence on its biomass. According to the results, this species mainly appeared in the southwest directions, on the slope of 60-90 %, at the height of 1850 to 2350 m above sea level, in clay loam soils with a pH of 6.58 to 7.25 and low salinity.
Reza Yari; Hosein Azarnivand; Mohammad Ali Zare Chahouki; Jalil Farzadmehr; Firoozeh Moghimi Nejad
Volume 21, Issue 2 , August 2014, , Pages 247-259
Abstract
This research was aimed to evaluate the environmental factors affecting the distribution of vegetation in Sarchah Amari ranglands, Birjand. After field visits, five vegetation types were selected based on physiognomy method and soil and vegetation sampling was done in key area of each vegetation ...
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This research was aimed to evaluate the environmental factors affecting the distribution of vegetation in Sarchah Amari ranglands, Birjand. After field visits, five vegetation types were selected based on physiognomy method and soil and vegetation sampling was done in key area of each vegetation type along the transect and within square plots with systematic-random method. Depending on the type and distribution of plant species, the plot size was calculated to be 1.3 and 16 m2 and 45 plots were established in each vegetation type along transects. The percentage of vegetation cover was measured in all plots but soil sampling was done in the first and last plots of each transect at soil depths of 0-30 and 30-80 cm. Soil characteristics including soil texture, percentage of lime, saturated moisture, gypsum, pH, electrical conductivity, sodium, calcium, potassium, magnesium, chlorine and topographic features including slope, aspect and altitude above sea level were measured. Soil and vegetation data were analyzed by PCA and ANOVA. The results of PCA showed that among the environmental factors, EC, the percentage of sand, slope, gypsum, organic matter and the soluble sodium were the most important environmental factors affecting the distribution of vegetation. Overall, these factors could explain 89.73% of the vegetation distribution. The results of ordination (PCA) showed that 70.74% and 18.63% of vegetation distribution were explained by the first and second axes, respectively. The first axis variables included the percentage of sand, electrical conductivity (EC), percentage of gypsum, sodium and the organic matter of first depth. According to the algebraic sign of variables, the distribution of vegetation was positively correlated with the percentage of sand while it showed a negative correlation with electrical conductivity (EC), gypsum, sodium and organic matter in first depth. The second axis variables of the ordination diagram included the percentage of slope and organic matter of second depth and according to the algebraic sign of variables, the distribution of vegetation had a negative correlation with the percentage of slope and soil organic matter of second depth.
Jalal Abdollahi; Hossein Naderi; Mohammad Reza Mirjalili; Monireh sadat Tabatabaeezadeh
Volume 20, Issue 1 , June 2013, , Pages 130-144
Abstract
Understanding the behavior and action of plant species and their ecological relationships with environmental variables is essential as an important part of the information required in range improvement, rehabilitation and proper utilization of rangelands. In this research, the effects of environmental ...
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Understanding the behavior and action of plant species and their ecological relationships with environmental variables is essential as an important part of the information required in range improvement, rehabilitation and proper utilization of rangelands. In this research, the effects of environmental factors on quantitative growth characteristics of Stipa barbata were investigated by ordination method in rangelands of Nodoushan –Yazd. For this purpose, twenty five sites were identified using the vegetation map and field visits, and in each reference area 30 plots were established along 3 transects of 500 m with random-systematic sampling. Inside the plots, a list of existing species, canopy cover, number of species and production were recorded. Three soil samples were taken from 0–30 cm depth. Soil samples were pooled together to obtain a composite sample. Clay, silt, sand, organic matter, lime, pH, electrical conductivity, sodium, calcium and magnesium were measured. Topographic features such as slope, altitude and aspect, were also recorded, and the type of formation was determined using geological maps. The relationships between growth parameters of stipa barbata and environmental factors were determined using Canonical Correspondence Analysis (CCA) method. Results showed that there were significant correlations among canopy cover, density and yield with soil factors. According to the results, among soil factors, soil texture, pH, SAR, Ca+2/Na+, calcium carbonate (T.N.V) and gravel had the most influence on canopy cover, density and yield. The effect of topography variables on growth characteristics was not significant. A significant relationship was found between growth characteristics of S. barbata and the type of geological formation.
Zeinab Jafarian; Hossein Arzani; Mohammad Jafari; Ghavamedin Zahedi; Hossein Azarnivand
Volume 19, Issue 3 , December 2012, , Pages 371-381
Abstract
This research was aimed to investigate the relationships between dominant rangeland species and environmental factors in the Rineh rangelands located on the southern slope of Damavand Mountain. Stratified random sampling method was applied and the study area was classified to 37 sample units based upon ...
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This research was aimed to investigate the relationships between dominant rangeland species and environmental factors in the Rineh rangelands located on the southern slope of Damavand Mountain. Stratified random sampling method was applied and the study area was classified to 37 sample units based upon elevation, slop and aspect.
In the study area, 750 plots 1m2 and 75 plots 25m2 were established. One hundred and fifty soil samples were dug at the depth of 0-30 cm and 16 soil properties including pH, CaCo3, bulk density, particle density, total phosphorus, total nitrogen, absorbed potassium, organic matter, saturation moisture, soil texture, field capacity, permanent wilting point, available water capacity and water holding capacity were measured in laboratory. After collecting the climate data, 16 climate factors including average relative humidity, average rainfall, average temperature, average minimum temperature, average maximum temperature in spring, summer and annual as well as annual frost days were selected to reconstruct the missing data. IRS images including red and near-infrared bands and PAN band as well as combined bands derived from RVI, NDVI, and PCA were selected. Regression equation was developed for each species using logistic regression. Results indicated that most of the factors including slop, aspect, average minimum temperature in spring, number of frost days, average daily temperature in summer, and most of the soil factors were entered in regression models. Also, satellite data were used as effective tools in showing the presence of plant species.
Zohreh Mirdeylami; Gholam Ali Heshmati; Hosein Barani; Yalda Hematzadeh
Volume 19, Issue 2 , September 2012, , Pages 333-343
Abstract
Recognition of ecological factors affecting the establishment and distribution of plants is necessary and the use of multivariate analysis could be useful to achieve this purpose. In the current research, relationship among the most effective environmental parameters on distribution and establishment ...
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Recognition of ecological factors affecting the establishment and distribution of plants is necessary and the use of multivariate analysis could be useful to achieve this purpose. In the current research, relationship among the most effective environmental parameters on distribution and establishment of vegetation types of Kachik Watershed was studied by multivariate analysis method. After providing land unit maps, density and canopy cover percentage were measured in reference areas of each land unit. Random-systematic method was used and sampling was performed on 53 quadrates established on 19 transects with intervals of 150 m. Soil samples were taken from the depth of 0-30 cm and pH, EC and percentage of clay, silt and sand were measured. Six separate ecological groups were identified by cluster analysis. Results of principal component analysis revealed that aspect, slope, pH, EC, soil texture and Ca had the most effect on distribution of ecological groups with correlation coefficients of 0.98, 0.96, 0.93, 0.89, 0.82 and 0.81, respectively.
Reza Yari; Hosean Azarnivand; Mahammad ali Zare Chahouki; Jalil Farzadmehr
Volume 19, Issue 1 , June 2012, , Pages 95-107
Abstract
In this study, the relationship between species diversity and environmental factors in the pastures in the Sarchah Amari ranglands of Birjand was investigate. For this purpose, after classification of vegetation types through physiognomy method, sampling from vegetation and environmental factors were ...
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In this study, the relationship between species diversity and environmental factors in the pastures in the Sarchah Amari ranglands of Birjand was investigate. For this purpose, after classification of vegetation types through physiognomy method, sampling from vegetation and environmental factors were accomplished in the key area of each vegetation type by random-systematic sampling. Plot size and the number of plots were respectively determined by minimal area and statistical methods. Afterward, in the key area of each vegetation type, three 300 m transects were established and 15 plots with 20 m intervals were located along each transect. Sampling of vegetation was carried out in all plots while soil samples were taken at the beginning and end of each transect from two depths of 0-30 and 30-80 cm. The list of plant species and canopy cover percentage were recorded in each plot. Percentage of soil gravel, clay, silt, sand, moisture saturation, pH, lime, organic matter, gypsum, electrical conductivity and soluble salts (sodium, potassium, chloride and magnesium) and topographic features (slope, aspect and altitude) were measured. For data analysis, species richness and evenness were calculated using different diversity indices (Simpson and Shannon -Wiener index of heterogeneity, Kamargov and Smith- Wilson as the homogeneity index). To determine the most important factors influencing variations of species diversity, principal components analysis was used. The results showed that electrical conductivity, gypsum, organic matter, slope, and sand were the most effective factors on diversity in the study area.
Asghar Farajollahi; Mohammad ali Zare Chahouki; Hosein Azarnivand; Reza Yari; BahraM Gholinejad
Volume 19, Issue 1 , June 2012, , Pages 108-119
Abstract
In this study, the relationship between environmental factors and distribution of plant communities in rangelands of Bijar protected region was investigated. Vegetation types were determined by using physiononmy method. Plot size was determined with minimal area method and after primary sampling the ...
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In this study, the relationship between environmental factors and distribution of plant communities in rangelands of Bijar protected region was investigated. Vegetation types were determined by using physiononmy method. Plot size was determined with minimal area method and after primary sampling the number of plots was determined by statistical method. In each vegetation type, sampling was done along four transects of 300 m length. 15 plots of 1m2 were established along each transect at 20 meter intervals. The type and the amount of existing species and the percentage of vegetation cover were determined in each plot. In each community, 6 profiles were dug within sampling unit. Soil samples were taken from 0-20 and 20-100 cm according to the boundary of separated horizons and type of existing plant species in study area. physiographic features including altitude, slope and aspect were measured and among soil properties, clay, silt, sand, lime, pH, EC, organic mater and gravel were measured. After collecting data, the Principal Component Analysis (PCA) was used to determine relationship between vegetation cover and environmental factors by PC-ORD software. The results indicated that there were relationships between measured factors and distribution of vegetation. Texture, gravel, lime, altitude and slope had the most influence on distribution of plant communities.
Gholam reza Zehtabian; Mehrnush Ghadimi; Ali Tavili; Jamal Bakhshi
Volume 17, Issue 3 , October 2010, , Pages 353-361
Abstract
This research was performed to investigate the relationship between environmental factors including water and plant composition. In other words, determining the most effective factors in distribution of vegetation types in Arak playa was the main aim of this study. To achieve this goal, the initial map ...
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This research was performed to investigate the relationship between environmental factors including water and plant composition. In other words, determining the most effective factors in distribution of vegetation types in Arak playa was the main aim of this study. To achieve this goal, the initial map of vegetation was provided and afterward water and vegetation sampling was done. Water parameters including K, Na, CL, Mg, %Na (exchangeable sodium percentage), Th, SAR, Co3, Hco3, So4, TDS (total hardness), EC, pH, and anions (sulfates, bicarbonates and chlorates) were measured. Multivariate data analysis techniques including principal component analysis (PCA) and canonical correspondence analysis (CCA) were used to analyze the collected data. The results showed that vegetation distribution pattern was mainly related to water characteristics such as Mg, TDS, Cl, anion, EC and Th. it can be concluded that according to habitat conditions, ecological needs and tolerance range of each plant species have significant relationship with water properties.
Kian Nadjafi–Tireh–Shabankareh; Adel Jalili; Nemat.. Khorasani; Ziba Jam zad; Uones Asri
Volume 15, Issue 2 , January 2008, , Pages 179-199
Abstract
The Genu Protected Area encompasses Kuh–e–Genu, a single and isolated mountain rising above the Persian Gulf Coastal plain. The Genu Protected Area is located in Hormozgan province, 30 km north west of BandarAbbas between latitudes (27°18′50″-27°29′16″ ...
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The Genu Protected Area encompasses Kuh–e–Genu, a single and isolated mountain rising above the Persian Gulf Coastal plain. The Genu Protected Area is located in Hormozgan province, 30 km north west of BandarAbbas between latitudes (27°18′50″-27°29′16″ N) and longitudes (55° 57′30″-56°18′4″E), at about 70 to 2347m above sea level. It covers an area of about43000 hectares. The main aim of this research is to identify relationship between plant associations and environmental factors. In this investigation the relationship between environmental factors and establishment and expansion of plant associations was carried out. The each plant association, 38 ecological factors including different soil characteristics such as soil texture, lime, saturation moisture, gypsum, acidity, electrical conductivity, soluble ions (Na+, K+, N, P, Mg2+, Ca2+, CL-, CO32-, HCO3- , SO42-) in two depth, elevation and slope of habitat were determined too. Multivariate method (Principal component analysis) was used to analyze the collected data. A matrix of vegetation and environmental factors was prepared and the ordination was done by the PCA using PC-ORD software. The results show that the measured environmental variables affected the plant association distribution pattern. The most important factors that have influenced plant associations separation are as follows: electrical conductivity, elevation, moisture saturation, organic matter, lime, K+, Na+, SO42-, Ca2+, CL-, Mg2+ and slope of habitat, respectively. The multivariate analysis expression, the effects of the complicated environmental variables on the plants in a simpler way and introduce the most important factors. As a general, each plant association depends on habitat conditions, ecological needs and tolerance shows a significant relation with environmental factors especially some soil properties.
Mohammad ali Zare Chahoki; Marjan Shafizade
Volume 15, Issue 3 , January 2008, , Pages 403-414
Abstract
The aim of this research was to study the relationships between presence of plant species and environmental factors in Chabeyki region of Yazd province. After delimitation of the study area, sampling was performed using randomized-systematic method. Within each type 5 parallel transects with 500 m length, ...
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The aim of this research was to study the relationships between presence of plant species and environmental factors in Chabeyki region of Yazd province. After delimitation of the study area, sampling was performed using randomized-systematic method. Within each type 5 parallel transects with 500 m length, each containing 50 quadrates (according to vegetation variations) were established. Quadrate size was determined for each vegetation type using the minimal area method. 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, electrical conductivity and soluble ions (Na+, K+, Mg2+, Ca2+, Cl-, , and ). Logistic regression technique was used to analyze the collected data. The results showed that the vegetation distribution is mainly related to soil characteristics such as gravel, saturation moisture, EC, pH, and lime. The presence of Cornulaca monocantha andCalligonum comosum has negative relation with saturation moisture and positive relation with gravel. Haloxylon aphyllum has also positive relation with pH. While, the presence of Seidlitzia rosmarinus has positive relation with Lime. EC has positive relation with the presence of Tamarix ramosissima.
Jalal Abdollahi; Hosein Arzani; Naser Baghestani; Mohammad Hasan Rahimian
Volume 13, Issue 3 , February 2006, , Pages 162-171
Abstract
Remote sensing is a method to produce updated information in vast area. Describing the model for utilization and processing satellite data in regard to developing a method for mapping forage production of arid regions were the purpose for this study. For this purpose Landsat ETM+ data used at Nodushan ...
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Remote sensing is a method to produce updated information in vast area. Describing the model for utilization and processing satellite data in regard to developing a method for mapping forage production of arid regions were the purpose for this study. For this purpose Landsat ETM+ data used at Nodushan area in 2002 . The study area covers about 60000 hectares and the annual precipitation is about 140-300 mm. in order to correct the necessary data 50 sites with different vegetation types using 25 quadrant of 1*2 m size and then awareged were used. To study the dependent variable of vegetation relations with independent variables of satellite data, vegetation indices and environmental factors; multiple linear regression analysis were manipulated using SPSS software. Then a suitable model was selected which caried predict the vegetation properties of the study area. Finally, production map was produced using ILWIS software. According to the results, mapping of forage production via remote sensing is possible even when its vegetation cover is less than 25%.
Taghi Mirhaji; Adel Jalili; Morteza Akbarzadeh
Volume 9, Issue 2 , September 2001, , Pages 729-742