IRANIAN JOURNAL OF RANGE AND DESERT RESEARCH
Year:2018 | Volume:24 | Issue:4 (69) |Papers Count:23

The present study was conducted to evaluate the potential of carbon sequestration in plant organs (root, stem and leaf) of Zygophyllum atriplicoides and Gymnocarpus decander and soil at two depths (0-15 and 15-30cm). The experiment was conducted in the Saleh-Abad region, 41km north of Haji-Abad, Bandar-Abbas Hormozgan, Iran, during 2012. Sampling of plant organs was performed by separating the leaf, stem and root. After determining the average dry weight of the study species, the content of organic carbon was calculated for both plant and soil. This study was carried out in two separate factorial experiments arranged using a randomized complete design. The first factor was the type of plant species in both experiments. The second factor was the plant organs in experiment I and different soil depths in experiment II. The results showed that the highest carbon sequestration was obtained at 0-15 cm soil depth. The effects of plant species and plant organs on the content of carbon stored in plant tissues was significant (P ≤ 0. 05) and (P ≤ 0. 01), respectively, while the interaction of those two factors had no significant effect on stored carbon. A significant difference was found between plant organs in terms of stored carbon. In both plants, the highest and lowest content of stored carbon was observed in stem and root, respectively. According to the results, the carbon content stored in Z. atriplicoides (45. 09 Kg) was 10. 7% more than that of G. decander (40. 74 Kg). Overall, the results of this study indicated that the highest carbon sequestration was obtained with Z. atriplicoides in the Saleh-Abad region.

In view of the increasing adoption of rangeland exclosure in order to rangeland improvement and carbon sequestration, investigation of its effects on the soil properties and calculation of the economic value of sequestered carbon is important. The aim of this study was to evaluate the changes in some soil physico-chemical properties, carbon sequestration rate and its economic value following grazing exclosure as compared with open grazing areas in Bozdaghi rangelands in North-Khorasan province, Iran. Therefore, in each area (exclosure and open grazing) three transects of 500 meter length and 200 meter intervals) were set up. Along each transect, five soil samples were taken at the depth of 0– 15 cm in a random – systematic method (15 soil samples in each area) and transferred to the laboratory. In the laboratory, some soil physical and chemical properties such as soil texture, bulk density, porosity, saturation percentage, pH, EC, percentage of organic matter, total nitrogen, the amount of cation exchange capacity, exchangeable sodium, potassium, calcium, and magnesium were measured and erodibility index was calculated by using the modified clay ratio relation. Data analysis was performed by using independent t test in SPSS v. 16 software. The results demonstrated that establishment of exclosure in Bozdaghi rangelands had significant positive effects on soil physico-chemical properties, and reduced the soil erodability index significantly (P< 0. 05). The mean value of sequestered carbon in the soil of exclosure area was significantly higher than that of open grazing area (P< 0. 05) and its economic value was estimated to be 4709760 toman per hectare. According to the results, especially the high economic value of sequestered carbon in the soil of exclosure area, establishment of exclosure in the study area is recommended.

A large part of rangelands in our country is located in arid and semi-arid regions. In this climate, the variability of vegetation is affected by changes in the energy flux in rangeland ecosystems and usually occurs in the composition and structure of vegetation over time. On the other hand, human factors and especially rangeland management have an influential role in maintaining rangeland stability or degradation. Accordingly, the monitoring of vegetation cover was carried out in winter rangelands of Ardebil province during 2008 to 2012. At first, using the available resources, the major habitats of the area were determined and then in each habitat a key area was selected for statistical analysis. Then, in each key area, canopy cover, density, and frequency were measured along three transects of 500 m within 30 plots of 1. 20*1. 20 m. Soil moisture and organic carbon were also measured. The results showed that, during a four-year period, shrub species had the main role in vegetation changes depending on the changes in rainfall and temperature. In the Moghan site, Artemisia fragrans was identified as the key species in vegetation changes due to the absolute dominance, high regeneration and direct response to seasonal and annual rainfall. Changes in soil cover were a function of changes in total canopy cover due to the relative stability of stone, gravel and litter cover. The results of studying the changes in vegetation, climate and soil moisture as well as soil erosion condition could be a good guide to correct the current management methods of these rangeland ecosystems.

Evaluation of important characteristics of soil and vegetation can inform us of the potentials of rangelands and determine the range condition. Soil surface characteristics directly affect vegetation. On the other hand, factors such as plant species, vegetative form and density affect soil characteristics. Therefore, this study was aimed to evaluate the effects of woody plants on soil characteristics using rangelands soil classification method (SSCC) in Khashab rangelands. Eleven soil surface indices within the plant patches of Ziziphus spina cristi and Ziziphus nummularia and Astragalus fasciculifolius as well as a mixture of trees and shrubs (Ziziphus spina cristi + Ziziphus nummularia) and interpatches (bare soil + litter) were measured along three transects of 70 m in five replicates. Then the factors measured in terms of three indices of stability, infiltration and nutrient cycling for each patch were classified. The results showed significant differences for stability index among the study patches, so that Ziziphus spina cristi + Ziziphus nummularia could improve soil stability. Infiltration index did not show significant difference between Ziziphus nummularia and a mixture patch (Ziziphus spina cristi + Ziziphus nummularia). More soil stability in the mixed patch of trees and shrubs (Ziziphus spina cristi + Ziziphus nummularia) could be promising for biological control in south winter rangelands of the country.

Rangelands as dynamic ecosystems respond to the disturbances such as climatic fluctuations and grazing management patterns. Prediction of spatial trend of these changes could be contributed to management planning and rehabilitation of degraded landscape. In this study, changes in the function of ecosystem, affected by livestock grazing, were investigated along grazing gradient. To this end, in the winter rangelands of Gorgan, functional features of the rangeland ecosystem including: nutrient cycling, infiltration and stability were measured at the set of points along grazing gradient. Measured parameters were analyzed using statistical methods and regression models to determine changes in ecosystem function along grazing gradient. The results showed a significant trend in functional indices along the grazing gradient. Points close to the livestock camp had the minimum value of functional indices while those at the end of the grazing gradient were found to be maximized. Comparison of different regression models using Akaike Information Criterion revealed that, as per infiltration index fourparameter sigmoid model and also for stability and nutrient cycling indices, three-parameter sigmoid model had the lowest AIC value and were the best models to predict functional changes along grazing gradients. The results of this study may be promising as rangeland model input to identify critical areas and can be used to predict management effects on productivity and sustainability of rangeland ecosystems.

Soil is one of the most important resources in each country and if it is not protected it will be lost due to erosion and gradually loses its fertility. Soil loss will fill the stream channels, reservoirs and cause serious damages like decreasing crop production per unit area. This study was conducted to evaluate the effects of watershed management practices including mechanical and biological measures to reduce erosion and sedimentation in Daremorid watershed in Kerman province. In this study, MPSIAC model parameters such as surface runoff factor, land cover factor, land use factor, current state of erosion factor, channel erosion factor, and sediment behind small dams were used. The results showed that the sediment yield was estimated to be 36653. 38 tons per year which is more than the sediment yield calculated in preliminary studies in this watershed (51378. 46 tons per year). Based on statistical analysis using SPSS software, the results revealed that there were significant differences between sedimentation and erosion, particularly in each of the parcels in the watershed.

This study was carried out in Bolban Abad, Kurdistan province, Iran, in order to investigate the changes in species diversity and functional diversity of vegetation under different grazing intensities. In this study, the data of three sites with different grazing intensity (low, moderate and heavy) were collected. Indices of species diversity including: richness (S), Shannon (H), evenness (E) and Simpson (D) and the functional diversity index (convex hull hyper-volume (CHull), Functional Richness (FRic), Functional Evenness (FEve), Functional divergence (FDive) and index Rao (Rao) were calculated for all sites. FD package and generalized canonical discriminant analysis (gCCA) were used in R 3. 1. 1to calculate these indices and determine the effect of grazing intensity on diversity indices. In addition, Duncan's test was used to compare the means of grazing intensities. Results showed that the species diversity indices, species richness index (S) and Shannon (H) were reduced by increasing grazing intensity. According to the results of generalized canonical discriminant analysis, species richness showed little change in response to grazing and CHull index showed an increase under grazing. Also, species functional traits were decreased with increasing of grazing intensity.

The monitoring of vegetation changes has a fundamental role in planning and management of environment. There are various methods to determine the changes in a region using satellite images that each has advantages and limitations. The use of vegetation indices is one of the methods to detect the changes. The aim of this study was to evaluate four vegetation indices including NDVI, SAVI, RVI and WAVI. This research was performed in Qeshm Island using Landsat images during 2001 and 2014. In this research, ETM+ and OLI data were used. After calculating each indicator, 100 sample training points were used to assess the accuracy of indicators by ENVI. 5. 3. Four classes including bare land, mangrove forests, agriculture and water were classified. Based on Dlapyan & Smith method, the product accuracy and user accuracy for each class were evaluated. The results showed that the SAVI index with the highest kappa coefficient, 0. 93 in 2014 and 0. 83 in 2001, had the best results and WAVI index with the lowest kappa coefficient, 0. 43 in 2001 and 0. 81 in 2014, had the weakest results. To evaluate the changes, crosstab method was used. The results showed that during 13 years the area of mangrove forests and agricultural lands and natural vegetation of Qeshm Island increased up to 21% and 60%, respectively.

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.

Vegetation has a substantial impact on soil properties and can modify soil chemical and physical properties through different mechanisms. Furthermore, nitrogen fixing plants are able to improve soil fertility by increasing nitrogen. The present study was conducted to investigate the effects of Astragalus cyclophyllon on some chemical properties of soil. To achieve the goal, soil samples under the canopy of Astragalus cyclophyllon and Bromus tomentellus as control plants (non-legume plants) as well as the control soil (where no plant is present) at 0-30 and 30-60 cm depths were taken in a completely randomized design. Then, the chemical properties of soil, including CaCO3, EC, pH, organic carbon, inorganic nitrogen and total nitrogen percentage in soil were measured. Moreover, a criterion plant was analyzed at laboratory scale to evaluate the effects of the target plant on the amount of total nitrogen, protein and production of understory plants. The results indicated that the amount of inorganic nitrogen, total nitrogen percentage and organic carbon in 0-30 cm soil depth was significantly different from other treatments (P<0. 05). This is also the case with the production, nitrogen and protein percentage of the criterion plant cultivated on the sampled soils from 0-30 cm depth under the canopy of Astragalus cyclophyllon. These factors have an inverse relationship with soil depth. EC and pH levels of soil under the canopy of Astragalus cyclophyllon were less than those of bare soil (control).

Understanding the physical and chemical characteristics of sediments of lakes and wetlands is important for sedimentology and erosion studies. Maharloo Lake is one of the most important lakes of Fars Province. Surface sediments of this lake consist of evaporitic and muddy sediments. For recognition of the nature of the sediments, samples were taken from lake bed and carbonate and evaporitic compositions including calcium-carbonate, calcium-solfate and sodium-chloride were measured. After omitting carbonate and evaporitic compositions, granolumetric analysis of terrigenous fraction was performed using hydrometry method and sediment classification was performed using Pettijohn (1975) Method. The result of the percentage of terrigenous and chemical fractions of surface sediments showed that most of the sediments were fine-grained terrigenous sediment, containing chemical salts. Terrigenous sediments are poorly sorted, skewed toward coarser sizes and have slightly gravelly, sandy mud texture. More than 90 % of sediment minerals in the lake is clay and less than10 % is gypsum, quartz, quartz sandstone, and limestone. Depending on the type of sediment, minerals, salts and frequency of deposits, the sediments of Maharloo Lake are prone to wind erosion and dust generation in the region.

Rangeland insurance can be one of the mechanisms to deal with inevitable risks of natural resources and may be the most appropriate strategy to reduce financial losses. Rangeland insurance in rural and tribal communities could be considered as a new phenomenon. In this research, the factors affecting rangelands insurance demand were investigated in Kalaleh district. The study was a survey research using questionnaires of pastoralists. In the questionnaires, several variables were examined. The target population was all pastoralists that had range management plan. Sample size was determined using Cochran's formula and estimated to be 115 people. In this research, to assess the factors affecting rangeland insurance demand econometrics patterns Logit model was used. Logit model parameters were estimated using maximum likelihood. According to the results, the effects of premium, forage residue, and membership in the council were negatively significant, while other factors were positively significant in rangeland insurance demand. Rangeland insurance can play an important role in range improvement and reclamation as well as increased production of rangelands. Accordingly, the need for implementation of educational and promotional programs to introduce the goals and benefits of rangeland insurance to the insurers in one hand and providing financial aids and improve the conditions for reimbursement of damages to the affected insurers in the other hand could provide the required facilities to help this part of society as well as greater willingness to extend their insurance and encourage other beneficiaries to insure their rangelands.

In order to study of drought stress in four sainfoin species (Onobychis Spp. ), a factorial experiments was conducted based on completely randomized design with four replications in glasshouse condition in research institute of forest and rangelands, Tehran, Iran in 2015. The factor A was four species as: O. michoxii O. cristagalli, O. sativa and O. sabnitens and factor B was four levels of drought stress: 100% field capacity (FC) as control, 75% FC, 50% FC and %25 FC. Seeds were sown in the pots and irriation was conducted based on drought stress levels. After 45 days from sowing date, data were collected for seedling fresh and dry weight, physiological traits as: chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, proline, water soluble carbohydrate, relative water content (RWC) and analyzed using SAS9 software. The results of analysis of variance showed significant effects of species, drought stress, and species by drought interaction (P<0. 01) for all traits except chlorophyll a. According to the results, seedling fresh and dry weight decreased by increasing of drought stress, while chlorophyll a and RWC increased. Overall, O. michoxii with higher values of chlorophylls, carotenoids, water soluble carbohydrate and seedling weight was more tolerant to drought stress, followed by O. sativa. These two species were introduced as relatively drought tolerant species.

Desertification is equivalent to land degradation causing reduced living and non-living organisms, especially in arid and semi arid ecosystems due to natural, human, and climate change factors. The present study was aimed to assess ICD and ESAs desertification models in Mehran plain, Ilam. Therefore, different desertification criteria and indices of both models were collected according to area characteristics and field observation in seven specified land units. In this research, four different indices including vegetation cover, soil characteristics, water and climate as the most important criteria in this region were selected and used for desertification intensity zoning. The results indicated that ICD method classified desertification intensity into two classes including moderate class (64. 92%) and high class (35. 07%) and ESAs method classified desertification intensities in 4 classes including fragile A (5. 55%), fragile B (14. 65%), fragile C (42. 5%) and critical A (37. 2%). According to the results, due to high adaptation to current condition of the area, flexibility in selecting the criteria and indices, application of GIS and using geometric average of indices for desertification intensity classification, ESAs method could be recommended as a suitable method for this region and similar regions.

Stachys byzantina is one the major increaser species in rangelands of north face of Alborz Mountain in Mazandaran province. The purpose of this study was to assess the effects of its invasion on vegetation under some disturbances in Vaz Chamestan summer rangelands in Mazandaran province. Vegetation sampling was carried out in exclosure, and invaded rangelands including abandoned dryland, moderate grazing and heavy grazing sites. The vegetation and some characteristics of Stachys were sampled in 1 m2 quadrates along transects. The results showed that Stachys byzantina had greater quantities in abandoned dryland and rangelands under moderate grazing. The cover percentage of total perennials, perennial grasses and forbs significantly reduced from exclosure to heavy grazing and abandoned dryland. Total annuals plants, annual grasses and forbs significantly increased in abandoned dryland. A significant negative correlation was found between cover percentage of perennials and the cover and density of Stachys byzantina. Moreover, the forage production of forbs was negatively correlated with the cover and density of Stachys byzantina. Multivariate analysis showed that species composition significantly changed under invasion, showing a reduction for palatable species.

Resilience indicators against environmental hazards are one of the basic criteria in planning and evaluating adaptation programs with the effects of natural hazards in rural areas. The present paper seeks to identify, formulate and validate the resilience indicators in rural areas to drought, so that planners and researchers can study these resiliency, drought and water crisis indicators, confirmed by the agreement of experts. The research method is descriptive-analytic, using questionnaires of experts and experts. In this research, different criteria and indices of theoretical literature were extracted and 35 questionnaires were subjected to arbitration by experts. In this research, 25 suitable indicators approved by executive experts and local experts have been introduced. The most suitable indicators and the most consensus can be indicators such as: livelihoods of the household, the growth trend or decrease in the natural resources of the village, the probability of immigration from the village, access to various agricultural water resources, the level of agricultural land (ownership), the state of insurance coverage and emergency services, agricultural development, household saving potential, and the prospects for non-farm business in the future. The results of this research can be the beginning for the development of a national model of rural resilience assessment indicators, the establishment of resilience index data banks and their quantitative reduction in order to achieve sustainable development and also reduce the effects of climate change and drought in rural areas of the country.

The southwest province of Iran has a dry and semi-arid climate, with about 250, 000 hectares of sand dunes; therefore a comprehensive review and overview of these features and their correlation with other features is needed. In this study, over 200 sand samples were collected from the mobile and not mobile sand dunes to study the grain size of sand dunes in Khuzestan. The results showed there was no significant difference in the mean grain size from east to west, along a 200 km transect of the sampled area. The mean grain size in the west was 2. 87 to 2. 14 φ scale (136 to 226 microns) and in the east 3. 05 to 2. 16 φ (120 to 223 microns). The standard deviation of particle size of the samples was good and fairly good (0. 71 to 0. 35 φ ). Using tilt condensation particle diameter in the range of sand dunes area, folk scale (0. 1 to 1 φ ) was positive. These distances represent 20 to 50 km with mean transported distance of 35 km for the west and 50 to 200 km transported distance with mean value of 125 km for the east section of the Khuzestan province for the sand dunes. For the transport distances, average transport distance could be divided into four categories, including 3, 12. 5, 35 and 125 km. According to the results, the source of particles of the sand dunes in Khuzestan province is local, mainly from northwest and west.

Recognition of spatial distribution pattern of plants is useful in describing the ecosystem stability, designing management plans and protective rehabilitative measures. In order to determine the distribution pattern of certain plant species in Ghamishloo National Park, six safe regions were selected. Three hundred sixty quadrates with the size of 1×1 m2 were established by using random-systematic method along six transects and the number of individuals of each species was recorded. In this study, dispersion indices such as clustering, Green, Lloyd and Morisita were used. Since a large number of plants with different densities were selected, the results of indices showed that density had no effect on distribution pattern. The values of Green's index showed a pattern between random and non-random (clumped) distribution pattern. Therefore, it is recommended to use maximum clumped values to determine the exact type of distribution pattern. Among the study indices, no specified maximum value was defined for Lioyd and Morisita regarding the clumped pattern. For this purpose, two formulas were defined to determine the maximum clumping and the results of indices were interpreted according to these formula.

Given the extent of saline lands in Iran, cultivation and utilization of halophytes and salt tolerant species under the condition that both water and soil are saline could be a viable option in production and extraction of vegetable oils from halophytes and salt tolerant species. The aim of this study was to investigate the potential of three halophytes namely: Suada fruticosa, Seidlitzia rosmarinus and Aeluropus littoralis as a source of edible oil as well as quantitative and qualitative oil analysis. For this purpose, seeds of three halophytes werecollected from saline soils of Aran & Bidgol, Iran. The extraction of fatty acids was performed bysolvent in Soxhlet method, and GC was used to analyze the fatty acids. The oil yield obtained from Suada fruticosa, Seidlitzia rosmarinus and Aeluropus littoralis was calculated to be 6. 61, 5. 73 and 2%, respectively. According to the results of seed oil analysis by gas chromatography, The seeds of halophytes species contains 16 fatty acids as: saturated fatty acids Butyric acid, Caproic acid, Caprylic acid, Capric, Lauric acid, Myristic, Palmitic acid, Stearic acid, Arachidic acid and unsaturated fatty acid Myristic acid Palmitoleic acid, Oleic acid, Elaidic acid, Linolelaidic acid, Linoleic acid, and y-Linolenic acid. Our results clearly indicate that the seeds of halophytes especially S. fruticosa could be used as a source of edible oil for human consumption.