فهرست مطالب

  • Volume:10 Issue: 1, 2020
  • تاریخ انتشار: 1399/01/11
  • تعداد عناوین: 8
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  • Atefeh Gholami, Amir Sadoddin *, Majid Ownegh, Mohsen Hosseinalizadeh, Alireza Yari Pages 1-15

    In this research, the impact of a carbon sequestration project, in the Hossein Abad Plain in Southern Khorasan Province of Iran, on the status of water and wind erosion was evaluated. The study area has a harsh climatic condition with low annual precipitation and is prone to well-known 120-day winds in summer. Since 2005, various soil conservation treatments (plantations, over-sowing, plantation aided by semi-circular rainwater harvesting structures) have been implemented in the area. The importance of this research is that so far there was no comprehensive assessment to indicate the impact of soil conversation measures on soil erosion. Therefore, current research aims to evaluate the effect of the carbon sequestration project on soil erosion during 2004 - 2016. Therefore, water and wind erosion was assessed by the Universal Soil Erosion (USLE) model and Iranian Research Institute of Forest and Rangelands Ekhtessasi – Ahmadi (IRIFR-E.A.) model, respectively. The general trend of water erosion using the USLE model indicates a reduction in soil erosion by greater than 19.9 t. ha-1. yr-1 over the whole study area which is larger than 2300 km2. Accordingly, all treatments had a significant impact on erosion in the study area whereby the greatest reduction in annual rate of erosion occurred in over-sown areas (by 5.92 t. ha-1. yr-1). The lowest erosion rate in 2016 was observed in the afforested areas (3.0 t. ha-1. yr-1). Wind erosion during 2004-2016 was improved from moderate and high erosion intensity classes to the low class in treated areas. According to the results of the USLE and IRIFR-E.A. models, the implemented carbon sequestration project has effectively reduced soil erosion in the study area. Therefore, the continuation of these treatments as well as extension programs to empower local communities is highly recommended.

    Keywords: Erosion, Carbon sequestration, Afforestation, Over-sowing, Water Harvesting
  • Fatemeh Palashi, Hossein PiriSahragard *, Majid Ajorlo Pages 16-27

    This study aimed to identify the most important physical variables affecting the distribution of four range plants species (Tamarix aphylla, Calligonum comosum, Prosopis spicigera and Salsola rigida) habitats and to prepare potential habitat map of the species using Maximum Entropy (MaxEnt) method in rangelands of Jiroft city, Kerman province, located in SE Iran. To this end, sampling of vegetation including species type and percent cover was conducted with randomized-systematic method in 2015. Sample size was determined as 60 plots with a quadrat size of 25-100 m2. For soil sampling, eight profiles were dug in each habitat and samples were taken at two depths, i.e., 0–30 and 30–60 cm. Results indicated that the classification accuracy of the model was acceptable and soil variables including EC, percentage of lime, organic matter, moisture content and texture had the greatest effect on the distribution of the studied plant species habitats. Correlations between the actual and predicted maps for Tamarix aphylla and Calligonum comosum habitats were at a very good level, Kappa = 0.81 and 0.79, respectively, for Prosopis spicigera habitat was at a good level, Kappa = 0.75, and finally for Salsola rigida was at a moderate level, Kappa = 0.53. These results indicate that the MaxEnt method can provide valuable information about the physical conditions of plant habitats in arid rangeland. Knowledge on physical characteristics of plant habitats can be useful in determination of potential habitats and rangeland improvement projects.

    Keywords: Plant distribution, Potential habitat, MaxEnt, Kappa index, Jiroft rangelands
  • Naser Baghestani, Mohammadtaghi Zare, Ehsan Zandi, Sedighe Zarekia * Pages 28-38

    The effects of grazing rest on rangelands are different in different climates and knowledge of these effects is necessary to apply correct management. For this purpose, this study was carried out on the percent vegetation cover (PVC) and forage production (FP) of range species at the Nir Range Research Station in Yazd province as a model of steppe rangelands of Iran. In the study area, different grazing intensities were applied until the end of the grazing season of 2006 and from then on, the whole area was under exclusion. PVC and FP were measured in each of the experimental plots once in May 2007 and again seven years later in May 2014. The results of vegetation data analysis in 2007 showed that the heavy grazing intensity applied in the past caused the reduced PVC and FP of two desirable species i.e. Salsola rigida and Stipa barbata as well as increased PVC and FP of Launaea acanthodes and increased forage production of Scariola orientalis as undesirable species. The results of vegetation data analysis in 2014 showed that the lowest PVC and FP of S.rigida was recorded in the experimental plots under heavy grazing intensity. In other experimental plots, there was no significant difference in PVC and FP of this species (p>0.05). There was no significant difference between PVC and FP of other species and total species in different experimental plots (p>0.05). Thus, during the 7-year rest period, although the negative effect of grazing on S.barbata is resolved, it remains on S.rigida and the resulting degradation is not completely compensated during this period and needs more time. Therefore, S.barbata showed better resistance to grazing as compared with S.rigida. According to the results, if steppe rangelands are grazed heavily in the short-term, intermediate-term grazing rest could improve the vegetation to the previous state.

    Keywords: Grazing intensity, Percent vegetation cover, Forage production, Stipa barbata, Salsola rigida
  • Reza Hasanpori *, Adel Sepehry, Hossein Barani Pages 49-56

    Land use change as the most important destructive factor in natural ecosystems is a globally problem that changes soil properties. Therefore, correct management and recognition of change aspects on each component of the ecosystem is necessary. This process causes land destruction, ecosystem instability, soil erosion, and more biological threats. Due to increasing land use conversion from rangelands to dryland farming, the effect of this phenomenon was studied on soil chemical properties in three land uses such as protected rangeland, dryland farming and abandoned dryland in Kian rangelands in Lorestan province, Iran in 2016. Soil properties including Soil Organic Carbon (SOC), pH, Electrical Conductivity (EC), and lime were compared between three land uses in two depths of 0-20 cm and 20-50 cm. Results showed that land use changes significantly affect these soil properties. In dryland farming, SOC was reduced in comparison to rangeland by 42% and 52% in the first and second depths, respectively. In contrast, the pH, EC and lime values were increased more than natural rangelands as 0.9%, 25.8%, 63.1% in the first depth, and 0.4%, 50%, 15.1% in the second depth, respectively. By stopping farming in abandoned dryland, the soil properties in abandoned dryland, were closer to rangeland than soil properties in dryland. These amounts in abandoned dryland ranked between rangeland and dryland farming. Our findings revealed that soil chemical properties were changed by conversion of rangeland to dryland farming via agricultural activities and human manipulation. Regarding these effects on soil properties and to keep ecosystems stability, attention has to be paid to land capability and prevention from wrong land uses.

    Keywords: Abandoned dryland, Kian, Land destruction, Land Use Change
  • Mahesh KumarGaur *, R. Goyal, Shiran. K Pages 57-72

    There is an enormous stress on livelihood analysis of rural communities and their economies. Village common property resources (CPRs) have played a substantial economic role for the sustenance in rural areas of the drylands. The CPRs of drylands of western Rajasthan shows a varied range of habitats due to strong functional disparities in topographic, geomorphological, climatic, edaphic and physiographic characteristics. The situation is aggravated due to severe biotic pressure on local ecosystem exists due to overgrazing and anthropogenic activities. There is an interplay between rural communities and their dependency for livelihood on the CPRs. It is a well-known fact that CPRs, more or less, act as a village ecosystem service provider in the life and economy of the rural communities of the drylands of India. The main objective of the present study is to make an evaluation of the role of CPRs as a village ecosystem, emphasizing its functioning as a service provider and the socio-economic repercussions of its degradation or loss. It has been revealed that CPRs have played a very important part in the economy of the surveyed villages and the reliance of landless, marginal and small households has remained much higher and critical for their subsistence. There is an urgent need for the sustainable management of CPRs by the village bodies with the active participation of communities.

    Keywords: Common property resources, Village ecosystems, Service centers, Community, Drylands
  • Mehrnaz Riasat *, Armin SaedMouchehsi, Ali Ashraf Jafari Pages 86-97

    In order to study the effect of drought stress on seedling morpho-physiological traits of alfalfa (Medicago sativa), the seeds of ten populations were collected in their natural habitats from different parts of the Fars province, Iran in 2013. A factorial experiment was conducted using 10 alfalfa populations and four water stress treatments of 100, 75, 50, and 25% Field Capacity (FC) based on a completely randomized design with three replications in the glasshouse of agriculture and natural resources research center of Fars province, Iran. Data collected for shoot and root fresh and dry weight, root and stem length, Root/Stem length ratio (RS) and free proline content. Data were subjected to analysis of variance, cluster analysis, principle component analysis. The main effect of population and water stress treatments were significant for all of traits (P<0.01) and population by water stress interaction effects were significant only for proline and root dry weight (P<0.01). The results showed high variation among populations under different water stress treatments. The means comparison among populations for all the water stress treatments showed that population of Kamal Abad Neiriz had high seedling growth coupled with long root length and was considered as drought tolerance to water stress that could be used to improve new varieties. The higher heritabilities were obtained for stem length (h2=0.52), root length (h2=0.48.8) and proline content (h2=0.47.7). According to cluster analysis, the four populations of Deh Kohneh, Dozkord, Kamal Abad, and Komhar that were placed into cluster 2 had higher mean values for many traits than other populations/clusters. This high variation could be used for breeding programs and making synthetic populations for improving alfalfa productivity.

    Keywords: alfalfa, Drought stress, Local populations, Genetic variation, Proline
  • Sahar SamadiKhangah, Javad Esfanjani, Mehdi Moameri, Ardavan Ghorbani* Pages 98-111

    Species Distribution Modelling (SDM) is an important tool for conservation planning and resource management. Invasive species represent a good opportunity to evaluate SDMs predictive accuracy with independent data as their invasive range can expand quickly. Thus, the aim of this study was to investigate the relationships between presence of Leucanthemum vulgare Lam. and environmental variables in Fandoghlou rangeland, Ardabil, Iran using logistic regression model. Sampling was conducted in six sites as presence/absence of L. vulgare by a systematic random method in 2016. Physiographic, climatic, surface coverage and density of L. vulgare were measured in sampling sites. In the beginning, middle and end of each transect, soil samples were taken from the depth of rootstock of range plants including L. vulgare. Soil attributes were measured in the laboratory. The maps of physiographic and climate were derived from digital elevation model, and selected soil attributes were derived using Kriging interpolation method. Derived regression equation from the presence of L. vulgare was applied to map the effective environmental variables, and a prediction map was produced for the study area. The comparison between the predicted and actual maps was assessed using the Kappa coefficient. Results showed that the presence of L. vulgare had a positive relationship with temperature and volumetric soil water content factors and had a negative relationship with electrical conductivity, sodium, diffusible clay factors. Therefore, L. vulgare type is significantlyaffected by the presence of these factors (p<0.01). The Kappa coefficient was 0.55 for derived predicted map. The evaluation of the model indicated that logistic regression was able to predict the distribution of L. vulgare habitats. The results of this study gave more insight and understanding from the habitats and effective environmental factors in L. vulgare distribution.

    Keywords: Species distribution modelling, Environmental factors, Invasive species, Namin County
  • Reza DehghaniBidgoli * Pages 112-124

    Since the halophytes species have an important role in such ecosystem balance and they have been grazed by livestock as supplementary forage, the awareness of livestock's desire to grazing and their preference values of these species is of high priority. Regardless of the importance of halophyte species in the livestock feeding in Iran, there is less published research on the livestock grazing from these species. In present study, the preference value of the five halophyte species (Seidlitzia rosmarinus, Salsola crassa, Aeluropus littoralis, Suada fruticosa and Anabasis setifera) was determined using preference index and timing methods in the marginal rangelands of Aran and Bidgol salt lake, Kashan, Iran in 2013-2016 during the grazing season. The preference values of these halophytes spices were assessed using Whittaker and Niering method. In the timing method, the animal grazing for 20 minutes was filmed for 1 to 2 hours after the flock arrival to the rangeland, and the grazing time of each species was recorded. According to the results of the analysis of variance, the species effect was significant for both grazing time and preference index (p<0.01). The results of the mean comparison showed that the Aeluropus littoralis with average values of 0.636 and 10.1 had a higher preference index and grazing time by livestock than that for other halophyte species, respectively. Also, in terms of livestock behavior for both factors, the highest grazing time was observed in October followed by November. The results of the species by grazing season interaction effect showed that the Salsola crassa and Aeluropus littoralis had higher preference indices for grazing whereas Seidlitzia rosmarinus and Aeluropus littoralis had longer times of grazing. According to the results of this research, the timing method was introduced as an appropriate method to determine the preference values of halophyte species in the studied area.

    Keywords: Grazing season, Playa, Halophyte species, Livestock, Palatability