Hasan Ghelichnia; Hamidreza Mirdavoodi; Ali Cherati Araie
Volume 30, Issue 2 , September 2023, , Pages 264-285
Abstract
Background and objective Today, predictive models of plant species distribution play a crucial role in assessing, restoring, protecting, and developing rangeland ecosystems. It is one of the most important tools to learn about species distribution and habitat suitability. This research determined ...
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Background and objective Today, predictive models of plant species distribution play a crucial role in assessing, restoring, protecting, and developing rangeland ecosystems. It is one of the most important tools to learn about species distribution and habitat suitability. This research determined ecological factors affecting plant composition, species response to environmental factors changes, and the potential of the target species in the study area using multivariate analysis. Based on this, with a better understanding of the ecological niche of this plant, the necessary recommendations can be made for using the species in rangeland improvement programs in similar habitats. Methodology Vegetation sampling was done by a systematic-random method during 2016-2018.Vegetation studies were carried out, including the percentage of canopy cover of species and the density of species inside the plots. Also, the percentage of litter, bare soil, stones, and pebbles was determined in each plot. For this purpose, five transects with the same distance were used. Then, six plots (with 2 x 2 meters dimensions) were established on each with the same distance. To investigate the effect of environmental factors on the distribution of the studied species, three soil samples were taken from each plot at a depth of 0 to 30 cm, and their physical and chemical properties were measured in the laboratory. Climatic factors such as average rainfall and annual temperature were collected using data from weather stations near the study area. To investigate the relationship between effective and significant environmental variables and vegetation and to choose the appropriate linear and non-linear method, DCA was performed on the vegetation data, and the gradient length was determined. A generalized additive model predicted plant species' response to environmental changes. Canoco software version 4.5 was used to analyze the data in this section. Results The results of conventional comparative analysis showed that environmental factors such as clay percentage, geographical direction, acidity, sand, saturated moisture percentage, organic matter percentage, average annual temperature and soil lime percentage in the studied habitats, respectively 10.3, 4.4, 3.3, 3.3, 1.6, 1.4, 1.4 and 1.3 percent of the variance in plant composition, play an important role in changes in vegetation in the habitats.It showed that A.specigera species respond to the amount of phosphorus, percentage of organic matter, electrical conductivity, percentage of nitrogen, percentage of clay, percentage of organic carbon, and altitude. This is following the monotonic decrease model. The response pattern of this species to the percentage of silt, percentage of sand, average annual temperature, average annual rainfall, the direction of slope, acidity, potassium, the apparent specific gravity of soil, percentage of soil saturation and percentage of slope follows the bell model (Unimodal) and limit its growth optimum for each of these factors is 21%, 60%, 16°C, 400mm, for eastern and southern slopes, 8, 650mg/liter, 1.4g/cm3, 39% and 40-50%. Conclusion The generalized incremental model provides valuable information to determine species' ecological needs. This information can be used in vegetation management and rangeland improvement operations in similar areas using the data from this research. Forage production is high in the studied species, suggesting its potential for increasing rangeland vegetation cover.
Hamidreza Mirdavodi; Hojatolah Zahedipour
Volume 11, Issue 4 , September 2019, , Pages 425-448
Hosein Arzani; Hamidreza Mirdavodi; Mehdi Farahpour; Mojganolsadat Azimi; Seyed Hasan Kaboli; Abasali Sanadgol; Morteza Akbarzadeh; Valiollah Mozafarian
Volume 12, Issue 4 , August 2019, , Pages 409-436
Hamidreza Mirdavoodi
Volume 21, Issue 2 , August 2014, , Pages 283-294
Abstract
Range improvement in saline rangelands is considered as one of the most important priorities. The first step in this process is the identification of suitable plant species, with emphasis on native species having suitable establishment, growth capacity ...
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Range improvement in saline rangelands is considered as one of the most important priorities. The first step in this process is the identification of suitable plant species, with emphasis on native species having suitable establishment, growth capacity and forage production under field conditions. Therefore, in this study, the compatibility of four plant species was studied in Meyghan playa of Arak. The research was carried out in a complete randomized block design with four replications, for three years (2008-2010). The study area has a mean annual rainfall of 327 mm. The soil texture is silty-clay-loam, with an electric conductivity ranged between 2.1-7.1 dS/m and a pH of around eight. Groundwater table level was over three meters. The seedlings were cultivated with a distance of 2.5 meter from each other in mid November. The establishment of seedlings, canopy cover percentage, vitality, forage production, and palatability were measured. Results showed that all species were successfully established. Significant difference was found for the canopy cover, vitality, palatability and forage production of species. The highest and the lowest canopy cover percentage were recorded for Atriplex canescens and Atriplex leucoclada, respectively. Halimion verrucifera and A.canescens, respectively, showed the maximum forage production and maximum vitality.. According to the results of palatability, a significant difference was found for forage, i ntake so that the highest and the lowest forage intake were recorded for H. verrucifera and Camphorosma monspeliacum, respectively. Overall, H. verrucifera, a native plant species in the study area, showed the superior palatability and more forage production as compared to other species. Therefore, the cultivation of this species in this area is recommended.
Gholamreza Goudarzi; Ali Farmahini Farahani; Hamidreza Mirdavoudi
Volume 19, Issue 3 , December 2012, , Pages 395-405
Abstract
Determination of allowable use of the key species of rangelands is necessary to calculate the rangeland capacity. Actual rangeland capacity could be determined through having the exact values of this factor for rangeland species and the destruction of vegetation, soil and water loss on rangelands can ...
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Determination of allowable use of the key species of rangelands is necessary to calculate the rangeland capacity. Actual rangeland capacity could be determined through having the exact values of this factor for rangeland species and the destruction of vegetation, soil and water loss on rangelands can be avoided. In this research, Artemisia aucheri, Bromus tomentellus, Kochia prostrata, Asperula glomerata and Buffonia koelzii were investigated as the key species of Arak Enjedan rangelands. A key area of one hectare was selected in Arak Enjedan rangelands and was fenced in the first year of the study. Then, 40 individuals were selected from each species and harvesting intensities of 25, 50, 75% and control treatment were implemented. Harvesting was done by a clipper monthly during grazing season for 4 years. The influence of harvesting was investigated in the second to fifth years through the study of changes in phenological characteristics, forage and seed production, vitality, and mortality and other characteristics of plant species. Results showed that increasing the harvesting intensity caused problems and decline of vital abilities of all species especially, As. glomerata and Br. tomentellus that are more palatable species. According to the results, an allowable use of 25% is recommended for Br. tomentellus and As. Glomerata while for Ar. aucheri, Ko. prostrata and Bu. Koelzii an allowable use of 50% was obtained with the least negative effects on plant characteristics. Results of the analysis of variance for forage production data were significant for all of the studied species in %1 level of probability.