Masoumeh Rahimi Dehcheraghi; Hossein Arzani; Hossein Azarnivand; Mohammad Jafari; Mohammadali Zare Chahouki
Volume 30, Issue 1 , April 2023, , Pages 48-59
Javad Moetamedi; Hosein Arzani; Mohammad Jafari; Mehdi Farahpour; Mohammad Ali Zarechahouki
Volume 26, Issue 1 , June 2019, , Pages 241-259
Abstract
The calculation of the grazing capacity requires the consideration of factors affecting it. Due to the effective factors, the long-term grazing capacity model was designed, and then the capacity of the rangelands was calculated. Grazing capacity was calculated by the proposed ...
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The calculation of the grazing capacity requires the consideration of factors affecting it. Due to the effective factors, the long-term grazing capacity model was designed, and then the capacity of the rangelands was calculated. Grazing capacity was calculated by the proposed model in four steps including estimating the average good production, calculation of available metabolic energy, the daily requirement of the animal unit and grazing capacity. Due to the drought condition of habitats and fluctuation of forage production in different years, one cannot calculate grazing capacity with once production measurement for the long-term. Hence, the average good production of habitats was determined and based on that, long-term grazing capacity was calculated. The average good production of Golestan Kouh, Vardast, and Pashmakan habitats in the statistical period of 6-7 years was estimated to be 425, 233.8 and 343.3 kg/ha, which are related to normal years in terms of rainfall. The grazing capacity of habitats in a quarterly period of four months was calculated to be 0.8, 0.3 and 0.5 animal unit per hectare so that if there is a drought for 12 consecutive months, there will be no damage to vegetation. Meanwhile, there is not much damage to the beneficiary and he will not have to sell too much of his livestock. The area needed for grazing of an animal unit in the rangelands was suggested to be 1.3, 3.3 and 2 hectare. This amount is recommended to be one hectare for a 30-year period based on a common method in range management plans. This indicates the need to pay attention to the factors affecting the grazing capacity and emphasizes the application of the proposed model in order to calculate the rangeland capacity.
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.
Mohammad Ali Zare Chahooki; Narges Naseri Hesar; Mohammad Jafary
Volume 25, Issue 2 , August 2018, , Pages 298-309
Abstract
The study was performed with the aim of modeling the distribution habitats of Eshtehard rangelands using Maximum Entropy Method and determining the factors affecting each habitat. Vegetation and environmental data including soil characteristics and topography were collected. ...
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The study was performed with the aim of modeling the distribution habitats of Eshtehard rangelands using Maximum Entropy Method and determining the factors affecting each habitat. Vegetation and environmental data including soil characteristics and topography were collected. The initial map was prepared based on slope, elevation and direction maps and satellite images. At each site, three transects with a length of 750 m were established, two transects along the most important environmental gradients and one transect perpendicular to them. A number of 45 plots along each transect was placed at a distance of 50 meters. The size of plot sampling was determined to be two square meters according to the type and distribution of plant species with minimal area method. Soil profiles were dug at the beginning and end of each transect. Sampling was done from the depths of 0-20 cm and 20-80 cm. The list of species and the percentage of vegetation in each plot were determined. For each sampling unit, the latitude and longitude data, slope, direction, and elevation were also determined. Then the desired characteristics were measured in the laboratory. GIS and Geostatistics methods were used to map the environmental variables. The species distribution models were produced using the species presence data and Maximum Entropy Method (Maxent). The Kappa coefficient index and the area under the curve (AUC) were used to evaluate the accuracy of the distribution maps. The agreements of actual and predicted maps for Pteropyrum olivieri was well (K=0/7) and it was acceptable for Halocnemum strobilaceum, Salsola richteri-Artemisia sieberi, Artemisia sieberi, Artemisia sieberi–Stipa barbata (K=0/66, 0/64, 0/57, 0/66).
Parvaneh Ashouri; Mohammadali Zare Chahooki; Afshin Danehkar; Adel Jalili; Behnam Hamze
Volume 25, Issue 1 , April 2018, , Pages 1-12
Abstract
Multivariate data analysis in ecology and biodiversity research is very important. Ecologists often need to test hypotheses about the effects of experimental factors on the entire community composition. To analyze multivariate data, the use of classical statistical methods is based on assumptions such ...
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Multivariate data analysis in ecology and biodiversity research is very important. Ecologists often need to test hypotheses about the effects of experimental factors on the entire community composition. To analyze multivariate data, the use of classical statistical methods is based on assumptions such as the normal distribution of data that are not usually observed in ecological data. To analyze multivariate data, the use of classical statistical methods is based on assumptions such as the normal distribution of data that are not usually observed in ecological data. Therefore, in recent years, nonparametric tests, based on permutation tests and distance or dissimilarity matrix, have been widely used to test the existence of differences in species composition in ecology sciences. The purpose of this paper is to introduce and familiarization with new ecological non-parametric multivariate tests related to ecology sciences such as SIMPER, ANOSIM, PERMANOVA and PERMDISP, with the aim of analyzing the composition of plant communities. In order to introduce these analyzes, vegetation data of six sites of rangelands located in the surrounding area of Tehran province were used and the composition of the plant communities of the mentioned areas was analyzed. SIMPER analysis showed that Stipa hohenackeriana and Bromus tomentellus, respectively, had the largest role in differentiating among the sites studied in arid and semi-arid regions. ANOSIM and PERMANOVA analyzes showed a significant difference of plant composition among the sites. According to the results of these tests, Firouzkooh-Alborz, Damavand-Semnan and Saveh-Salafchegan sites had more similarity in terms of composition of vegetation. PERMDISP analysis showed that heterogeneity and multivariate dispersion of species coverage were significantly higher in Salafchegan and Saveh sampling sites. Therefore, according to the results, it can be stated that in order to preserve biodiversity in the study sites, at least three separate management plans are needed. Also, according to SIMPER analysis results, management plans to preserve the biodiversity of the areas studied can be supported by the distinct species identified in each site.
Firoozeh Moghiminejad; Mohammad Jafari; Mohammad Ali Zare Chahooki; Yaser Ghasemi Arian; Asghar Kohandel
Volume 21, Issue 4 , March 2015, , Pages 643-650
Abstract
Exclosure is the prevention of livestock access to all or part of the rangeland for one year or a few consecutive years, performed with different goals. This research was aimed to investigate the effect of exclosure on soil physical and chemical properties as well as three main elements of N, P, and ...
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Exclosure is the prevention of livestock access to all or part of the rangeland for one year or a few consecutive years, performed with different goals. This research was aimed to investigate the effect of exclosure on soil physical and chemical properties as well as three main elements of N, P, and K in Nazarabad region, Karaj. Soil sampling was performed in both sites of exclosure and grazing. Soil samples were taken from the beginning, middle and end of the four transects, established in each region, at two soil depths of 0-20 cm and 20-80 cm using systematic random sampling. The following soil properties were measured in the lab: pH, EC, organic matter, saturation percentage, and N, P, K. According to the obtained results, the effect of exclosure on soil N, P, and K was significant; however, exclosure had no significant effect on pH, organic matter and saturation percentage. Overall, our results clearly showed the positive impact of exclosure on soil physical and chemical properties.
Hossein Arzani; Javad Moetamedi (Torkan); Mohammad Jafary; Mehdi Farahpour; Mohammad Ali Zare chahooki
Volume 20, Issue 2 , June 2013, , Pages 271-250
Hamed Joneidi Jafari; Hosein Azarnivand; Mohammad Ali Zare Chahooki; Mohammad Jafary; Ebrahim Kargari
Volume 20, Issue 2 , June 2013, , Pages 298-308
Hosein Azarnivand; Yaser Ghasemiaryan; Reza Yari; Mohammad Ali Zare Chahouki; Esfandyar Jahantab
Volume 19, Issue 2 , September 2012, , Pages 297-305
Abstract
The aim of this study was to investigate allelopathic activity of aerial and underground organs of mountain sagebrush (Artemisia aucheri) on seed germination features, root length, shoot length and seed vigor of Festuca ovina.For this purpose, species of mountain sagebrush were collected from Taleghan ...
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The aim of this study was to investigate allelopathic activity of aerial and underground organs of mountain sagebrush (Artemisia aucheri) on seed germination features, root length, shoot length and seed vigor of Festuca ovina.For this purpose, species of mountain sagebrush were collected from Taleghan rangelands in Tehran Province and then were dried in direct sunlight and grinded.Powder derived from aerial and underground organs to the amounts of 3, 6 and 9 grams were separately mixed with 900 grams of sand in completely randomized blocks with four replications. In each pot, 10 seeds were planted at a depth of 2-3 cm. Germination percentage, germination velocity, seed vigor, root length, and shoot length were measured. Data analysis was performed using MSTATC software and mean comparisons were carried out using Duncan's test. Results showed that there were no significant differences among measured factors. Also, the shoot and root lengths showed significant differences at probability levels of 5% and 1%, respectively. According to the results, Artemisia aucheri caused a reduction of root length in Festuca ovina.
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.
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.