IRANIAN JOURNAL OF RANGE AND DESERT RESEARCH
Year:2017 | Volume:24 | Issue:1 (66)|Papers Count:22

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.

This research was aimed to classify the drought in arid and semi arid regions of Isfahan province using TOPSIS technique. Four climatic elements including temperature, number of rainy days, annual rainfall and relative humidity were used for five meteorological stations during the 20-year period (1994-2013). For validation of the proposed method, the output of TOPSIS method was compared with the output of DPI, PNPI, RAI and SPI. For this purpose, Spearman's rank correlation coefficient was used between the quantified values of drought severity index and annual rainfall. The results showed that there was a strong correlation between the drought severity index and annual rainfall in the TOPSIS algorithm in all studied stations. Therefore, the validity of the model was approved. Generally, moisture fluctuations are high in the study area. In other words, drought is completely independent from station to station and from year to year, so that Nain and Isfahan had the highest (13 years) and lowest (7 years) number of drought years, respectively. In the TOPSIS algorithm, drought is closer to its real value since more parameters are used compared with previous simple methods. In this method, there is a systematic relationship between climatic elements in a year and other years, through which evaluation and ranking of drought is carried out. Finally, it could be concluded that the TOPSIS algorithm is a method capable of determining and ranking drought.

The relationship between soil and plant has long been considered, leading to the greatest benefits to humans. This study was aimed to investigate the effect of soil properties on establishment of Haloxylon aphyllum. For this purpose, in two adjacent regions with different soil, some of the physical and chemical properties of soil and growth parameters of Haloxylon were measured in Gonabad and Mah'velat cities. Data were analyzed using the Minitab software through the two-sample t test. According to the results, soil parameters including the percentage of lime, potassium and phosphorus had no significant effect on the growth of Haloxylon. However, increased soil saturation percentage, reduced soil pH and increased amount of carbon and nitrogen in furrow cultivation, and low electrical conductivity in the pits filled with sediments as well as fine soil texture in two cultivations led to improve the growth of Haloxylon. Also, soil salinity does not affect the viability of this species.

Natural resources are mostly considered as a common property of different relevant actors that may have different and competitive interests. In many cases, these stakeholders may have conflicts over natural resources due to their livelihood needs or other interests. Managing these conflicts is an important element of natural resources management. The purpose of this paper is to explore the actors and their interests and resources in the Dorahan and Cheshme Ali Watersheds, located in the Chaharmahal and Bakhtiari Province, as well as to illustrate the conflict pattern among them. A multiple case study methodology with multiple units of analysis was utilized. These two watersheds, comprising six villages, had various natural resources with different private and nationalized land properties. There was some reports showing property conflicts between rural people and the Natural Resources and Watershed Management Administration of this province. The data were collected using qualitative techniques such as observation, semi-structured interviews, focus groups, mapping and diagrams.The data were finally analyzed using the Conflict Pattern Assessment technique. The external actors and rural and nomadic communities had different interests in the watersheds, which caused conflicts among them. Moreover, these conflicts were at different levels. The highest level of conflict was identified between the communities and natural resources conservationists, while the conflict with other external actors was in a form of dissatisfaction of the services received. In addition, the conflict was reported inside the communities; between the households and rural organizations such as cooperatives and councils. The most important consequences of these conflicts have been weakening rural households' livelihoods, increasing rural- urban emigration and decreasing social capital. Despite the negative impacts, the conflict has had some short-term positive impacts on improving rangelands vegetation due to prohibiting rural livestock early grazing.

Range management plans (RMPs) are one of the main tools for the management and utilization of rangelands in Iran. Range size, number of animal units, and rangeland users are considered as the most important factors influencing RMPs. This study was conducted in the rangelands of Isfahan province in 2008 in order to study the relationship between range size, the ratio of permitted animal unit to existing animal unit and number of rangeland users with range condition. Accordingly, the list of RMPs was prepared. Then, the range size, the number of permitted and existing animal units and rangeland users were determined. After that, the range condition was determined using four-factor (winter rangelands) and six-factor methods (summer rangelands).Finally, the relationship between range size, the ratio of the permitted animal unit to the existing animal unit and number of rangeland users (separately and commonly) with range condition was verified by using spearman correlation and discriminate analysis.Results indicated that there was a significant relationship between range size (P£0.01) and the ratio of the permitted to the existing animal unit (P£0.05) with range condition in summer rangelands. Therefore, it is concluded that range size and animal unit could be considered as one of the factors affecting rangeland degradation.

Wind erosion is one of the most important natural processes in arid and semi-arid areas, occurring as a result of erosive winds. Wind speed, frequency and duration should be considered in studies related to wind erosion. Kashan Erg is one of the most important sand dunes complexes in Iran. To study the relationship between the wind characteristics (Uni- directional index, windness index, wind duration and frequency) with Erg morphology and also study the changes of sand flow rate in various regions, anemometers data were obtained from synoptic stations of Kashan, Ardestan, Jangalbani Badrod, Garmsar and Qom. Then, the interpolation map of sand transport and interpolation map of average and maximum wind in Kashan Erg were drawn using GIS software. Finally, the analysis results showed that the interpolation map of sand transport corroborated the results obtained from interpolation map of average wind, because sand transport rate and average wind speed were reduced from east to west of the Erg. Therefore, it is found that wind frequency and duration have more important role in the sand transport and morphology of the study area as compared with the wind speed. In addition, the comparison of Erg morphology and anemometer results in different stations showed that the spring and summer winds had the highest role in the Erg morphology.

Todays, conversion of forests and rangelands to croplands has made concern about soil and environmental degradation and global climate change. Knowledge of the effects of land use change on soil properties is necessary and can be a solution for identifying sustainable managements in any region in order to prevent soil degradation and reach to sustainable production and environmental purposes, either. In the past decades, large part of Avard rangelands has been converted to croplands. In recent years, gardening on these low efficiency agricultural lands has been suggested. The aim of this study was to investigate the effects of gardening on some soil physical and chemical properties compared with rangeland and cropland in Avard region. At first, the study area was identified by field survey and then, three composite soil samples were obtained from depth of 0-30 cm of key area of each treatment (rangeland, walnut Garden, walnut–apple garden, cereal farm, and frijol farm). Some soil physical and chemical properties including texture, aggregate stability, bulk density and porosity, organic carbon, pH, and electrical conductivity were measured in laboratory and soil erodibility index was calculated by using the modified clay ratio relation. Data analysis was performed by SPSS.16.0 software and one way analysis of variance. In order to compare the means of studied parameters, tukey test at a significance level of 5% was applied. The results demonstrated that soil aggregate stability and electrical conductivity were significantly improved (P<0.5) as a result of gardening on the low efficiency agricultural lands, but other soil properties such as soil organic carbon were not significantly improved (P>0.5). According to the results, it can be concluded that the best land use in the study area is natural rangelands. Establishment of orchards in the low efficiency arable lands of the study area is recommended, either.

Perennial shrubs cause to change the soil quality of their habitat through litter fall and root penetration. This research was aimed to investigate the effects of two range species on the soil surface. The study was conducted in a part of steppe rangelands in Tabas County. Soil sampling was performed completely random at 0-20 cm soil depth with two treatments including beneath the stratum and control group. Soil chemical properties including EC, organic matter and soluble sodium and chlorine were measured. Data analysis showed that the soil chemical properties measured beneath the stratum of both species differed significantly as compared with the control group (P<0.01). The results showed that the increased content of these factors beneath the stratum of the study species was different, so that the content of these factors beneath the stratum of Atriplex lentiformis was manifold more than that of Salsola yazdiana. According to the obtained results, the pure use of Atriplex lentiformis could result in salinization of the soil surface.

Global warming has devastating effects on the lives of organisms, causing damage to natural ecosystems, floods, droughts and climatic and ecological imbalance. Resonance effects of greenhouse gases in the atmosphere as a result of carbon dioxide concentration causes warming, melting polar ice caps, massive flooding, and deforestation. Biological carbon sequestration is soil and plants' ability to absorb carbon dioxide from the atmosphere and store it in plant and soil. Therefore, it is a method that helps to reduce atmospheric carbon and to mitigate the consequences of climate changes. In this project, the effects of restoration rangeland practices (contour furrow) on carbon sequestration were investigated in Khalifan region of Mahabad. For this purpose, in each study site (contour furrow and control), four 100-m transects were established. Along each transect, five plots spaced 20 m apart were set up systematically. At the beginning and end of each transect, a profile was excavated at two depths (0-15 and 15-30 cm). Soil and plant samples were transferred to the laboratory. Plant biomass was measured in all plots by cutting and weighing method.Carbon sequestration rate was determined for each of the samples. The data were analyzed by ANOVA and T-test. The results indicated that the highest rate of carbon sequestration in the study sites belonged to the litter. The results demonstrated that the rate of carbon sequestration in both biomass and soil in contour furrow site was higher in comparison with control site. This can be due to the positive effect of contour furrow practice on the amount of participation storage in soil, run off and erosion control and increasing the vegetation.

The purpose of this study was to investigate the relationship between rangeland plants production based on total production and life forms of grasses, forbs, and shrubs with topographic factors (altitude, slope, and aspects) in Sabalan rangelands, Ardabil province. To determine the annual total production, the amount of production was estimated using harvesting method in one square meter plots (totally of 216 plots) under the altitude range of 1200 to 2900 meters a.s.l. Using topographic maps, the digital elevation model was derived and classified maps of elevation, slope, and aspect were derived. Then, in each plot, information such as elevation, slope, and aspect was extracted. The correlation between life forms and topographic factors was analyzed using multivariate regression method. The results showed that there was a significant relationship between the production of life forms such as grasses (P<0.01), forbs (P<0.01) and shrubs (P<0.05) with topographic factors; however, there was no significant relationship between total production and topographic factors (P>0.05). The production of grasses, forbs and total production had direct relationship with slope; however, the production of shrubs decreased with the increase of slope. The production of grasses increased with altitude, and in the east-faced slopes, it was estimated more than the other aspects. The production of forbs decreased with the increase of altitude and was higher in the east aspect in comparison with the other aspects. The production of shrubs and total production in the middle altitude and in north- faced slopes were more than the other classes and aspects according to the suitable ecological condition and low degradation. Although it is obvious that elevation, slope, and aspect can change and affect the production, this effect is unknown, especially in the connection with life forms and the process of change. Overall, it can be concluded that these results could be used in the management of these rangelands, particularly in the improvement and rehabilitation practices.

Huge parts of Urmia Lake have been dried up in recent years. As a result, vast areas of salty fine sand dunes, which are very susceptible to wind erosion, have been formed. This study was conducted to investigate the performance of Particle Size Distribution (PSD) models in description of sand dune PSDs and predicting wind erodibility by using PSD models in parts of western coast of Urmia Lake. Totally, 48 samples from a grid of 500m × 500m were collected. PSD of the samples was determined by dry sieving method. Statistical parameters of grain size including mean, sorting, skewness and kurtosis were calculated. Performance of nine PSD models in describing the grain size distribution was assessed by the coefficient of determination (R2), Root mean square error (RSME) and Akaike criterion (AIC) of the models. To determine wind erodibility of sand dunes, mass fractions of aggregates<840, <420, 420-840, <100 and 100-840mm in diameter were determined. Results showed that average of mean grain size of sand dune samples was 310mm (1.69f), which in comparison with many other desert areas of world, are composed of relatively coarse sands, poorly sorted and very leptokurtic. According to the different efficiency, the Fredlund model showed the best performance in describing PSD of the samples. Averagely, around 97% of particles of the samples are less than 840mm in diameter therefore the study area is very susceptible to wind erosion. About 80% of particles i accounted for particles susceptible to erosion by the processes of suspension and 17% particles are prone to erosion by processes of saltation.

This research was aimed to investigate the effects of different harvesting intensities on forage yield and vitality of Aeluropus littoralis, as a key and important range species in the Tez Kharab rangelands, Urmia, Iran. The study was conducted in the rangelands around Urmia Lake and a 0.5-ha exclosure was selected and fenced in the first year of the study. The treatments consisted of four harvesting intensities including 0%, 25%, 50%, and 75%. Harvesting treatments were applied for four years during the growing season and at the start of livestock grazing. The harvested forage was air-dried and weighed to calculate the forage yield. In addition, the remaining yield of control and harvesting treatments were cut, dried, and weighed. Data were analyzed using a split-plot design in time. Finally, the effects of changes in phenological characteristics, forage yield, plant vitality and mortality were investigated. The effects of year and harvesting intensities as well as interaction effects of year and harvesting intensity were significant on forage yield (P<0.05). This indicates that forage yield differs in different years depending on climate conditions. Our results clearly showed that increased utilization led to reduced plant vitality. According to the obtained results, a harvesting intensity of 50% could be recommended as an optimal allowable use of forage with the least negative impacts on plant vitality.

Wetlands in the central Iran lakes are considered as part of desert ecosystems and their destruction leads to adverse consequences. In central part of Iran, climatic and human factors have created significant differences between dry and wet surfaces of Gavkhooni wetland in recent decades, leading to produce more dust in central part of Iran. The aim of this research was to assess the impact of dried bed of Gavkhooni wetland on the production of the internal dust in Isfahan province by using remote sensing and storm roses in the period of 22 years (1991- 1992 to 2011-2012). For this propose, the landsat imagery and anemometer data were used. After geometric and radiometric corrections, Normalized Difference Water Index (NDWI) was calculated and the dry and wet surfaces were separated. To determine wind erosion threshold velocity, undisturbed soil samples were transferred to the wind erosion meter. Then, the number of dusty days in the synoptic station of Isfahan was calculated based on the wind speed greater than wind threshold speed. Relationship between the number of dusty days and dried bed of wetland was evaluated with correlation analysis. Finally, to determine the dusty wind direction from the side of Gavkhuni wetland to Isfahan station, annual and seasonal wind roses and storm roses were plotted and evaluated. The results of this study based on the artificial neural network model showed that the most important factors influencing the bed of the Gavkhuni wetland were input flow rate, evaporation, drop in groundwater level, temperature, and rainfall, respectively. The results of the correlation analysis showed that there was a significant inverse relationship between the number of dusty days and dried bed of wetland in the seasons of autumn, spring, summer and annual scale in Isfahan station. Also, results of storm roses showed that dusty winds did not blow from wetland toward this station.

The aim of this study was to estimate and map the plant group and total aboveground phytomass using Landsat 8 images in the rangelands of Sabalan Mountain. Images were selected on the 19th of July 2013 and field data were collected in April and July based on maximum matching with the phenology of the study area and in the closest date to the time of image acquisition. Twenty-four sampling sites on six vegetation types were determined. In each site, 9 sampling plots, based on previous studies, which are required for minimum sample number according to the variance of vegetation distribution, were determined in a systematic-random method, and the aboveground phytomass of vegetation groups, such as grasses, forbs, shrubs and total, were determined using the harvesting method. Initially, to calculate vegetation indices, the averages of 16 pixel values of the location of sample units from the corrected images were derived and transferred to the software environment. The correlation matrices between the derived pixel values and field collected data for the 24 selected vegetation indices were calculated and used for the estimation of grasses, forbs, shrubs and total aboveground phytomass. The results showed that indices such as RVI, TNDVI and GNDVI had the highest correlation with the aboveground phytomass of grasses, PD312, IO and PD311 with the aboveground phytomass of forbs, RDVI, DVI and RVI with the shrubs, and PD311, PD321 and PD312 with the total aboveground phytomass (P<0.01). In the second stage, three of the indices, having the highest correlation with the aboveground phytomass of each group and entire previous stage, were selected, and Landsat8 images were used to calculate the aboveground phytomass of each vegetation group and the total aboveground phytomass was calculated. The aboveground phytomass maps of each group and the total aboveground phytomass were controlled with sampling points to assess the accuracy. The results of this study showed that the best maps were obtained using the TNDVI index for grasses aboveground phytomass, PD312 for forbs, RVI for shrubs groups and PD311 for the total aboveground phytomass. Moreover, some indices, such as PD311 and RVI, could be used for all growth forms and estimation of total aboveground phytomass (P<0.01) and (P<0.01). In general, Landsat 8 data could be used to estimate and map the aboveground phytomass of vegetation groups and to determine the carrying capacity of the total aboveground phytomass in Sabalan rangelands, having advantages based on cost, time and the ability to monitor large areas with repeatability potential in comparison with the ground-based methods.

Soil is a major reservoir of terrestrial carbon, but human activities around the world including land use change lead to a significant emission of carbon from the soil. It seems that soil organic carbon has been significantly decreased due to the land use changes over the last century in Iran. Therefore, the objective of this study was to investigate the effect of land use change (rangeland to agriculture) on organic carbon stock and some biological indices of soil quality (soil organic carbon (SOC), basal soil respiration (BSR), microbial biomass carbon (MBC), microbial quotient (MQ), and metabolic coefficient (qCO2) in east of Khuzestan province. Soil samples were collected in eight replicates and two depths (0-15 and 15-30 cm) in both land uses. Results showed that except qCO2, the amount of TOC, MBC, and MQ in agricultural use decreased significantly as compared to rangeland. According to the results, C stock of agricultural lands in 0-15 and 15-30 cm layers was 19.5 and 8.3 Mgha-1, showing 34 and 47 percent decrease when compared to natural rangeland with 29.7 and15.9 Mgha-1 C stock. The SOC content in 0-10 cm soil layers of agricultural use and natural rangeland was (8.47 and 5.28 gKg-1) and (13.29, 6.55 gKg-1), respectively, demonstrating 60 and 71 percent reduction in agricultural lands. In addition, in 0-15 and 15-30 cm layers of agricultural lands, MBC (60 and 71 percent), MQ (37 and 65 percent) showed reduction and qCO2 increased 3-4 times when compared to natural rangeland. Results show that agricultural activities lead to considerable loss in total organic carbon and half of organic carbon stock in the soil. Limitation of organic carbon in agricultural land use makes noticeable reduction in MBC than other properties. Thus, it can be used as a suitable indicator for monitoring changes of organic carbon in the soil.

This study was conducted to calculate the amounts of carbon storage and effects of environmental factors on C storage of Halocnemum strobilaceum in the coastal rangelands in Bordekhoon of Boushehr province. The plant samples were cut (above and underground), and soil samples were taken at two depths (0-30, 30-50 cm) in five sampling and control sites. The plant samples (leaves, branches, and roots) and soil factors (percentage of sand, clay and silt, EC, pH, SP, T.N.V, Bd, OC, and N) in each sample point were determined by laboratory methods. Organic carbon in plant parts and soil were determined using burning and Walky-black methods. The relations between soil parameters and C storage in above and below ground biomass were determined using principal component analysis and cluster analysis. The result showed that the amount of C storage in above-and below-ground biomass was 248 and 18.62 gr/m2, respectively. Furthermore, the amount of C stored beneath the plant had a significant difference with stored carbon at a distance of 1.5 m. The result of variance analysis of soil parameters and soil carbon storage with a central site for other parameters showed a significant difference at the 5% level. The average soil carbon storage was 4152.75gr/m2. The amount of carbon stored in second soil depth was more than the first depth, due to the root penetration and root development. Total carbon storage in the plant biomass of the study habitat was 3728 tons in 20 ha of species distribution and 153800 t/ha at the regional level, showing the important role of soil in carbon storage. The results of the effect of soil parameters on carbon storage by PCA and cluster analysis showed that, the most important parameters influencing soil carbon storage were EC, pH, percentage of sand and silt and bulk density.

This research was aimed to modeling the height and distance of sand dunes in central deserts of Iran (Kashan Erg and Jen Erg) as well as their classification. Results of identifying sand dunes in the study areas showed that there were considerable variations in formation of sand dunes in central deserts of Iran. Quantitative modeling of height based on DEM (80 × 80m) showed that the average height of sand dunes in Kashen Erg and Jen Erg was 35m and 6.84m, respectively. The reduced height in Jen Reg was due to the 37% frequency of sand dunes area and regardless of these dunes, the average height was calculated to be 8.63 m in Jen Reg, of which 90% was in a height class less than 20 m. On the other hand, the frequency percentage variation of sand dunes height classes is higher in Kashan Erg, so that over 80% of Kashan Erg is in a height class less than 50m, while 87% of Jen Erg is in a height class less than 10m. In Kashan Erg, the height of sand dunes is low and gradually increases in the center of Erg, reaching to the highest height of sand dunes. Quantitative modeling of relations between the height and distance of dunes in Jen Erg indicated that the sand dunes activity was restricted to the upper part of the dunes. In Kashan ERG, the comparison of fixed, linear and compound dunes showed that the fixed dunes would be formed at a closer distance as compared with two other types.

Due to the limited water resources and low rainfall, finding proper solutions to reduce the water consumption for vegetation production in natural areas has received attention more than ever before. For this purpose, this research was aimed to investigate the effects of superabsorbent polymer and Plantbac panels on the efficient use of water on Saxaul (Haloxylon persicum) growth. The study was conducted in the Agricultural and Natural Resources Research Station in Semnan province, Iran. Irrigation in this study was performed according to the soil water suction, reaching to pressures of 1.0, 5.0, and 15.0 bars. The water consumption in each of the aforementioned suctions was to reach the field capacity of the same soil. In addition to the above treatments, rainfed treatment was also considered. Before planting the seedlings, the superabsorbent polymer was mixed with the soil of seedling pits at a weight ratio of 0.6%. The Plantbac panels were placed in the bottom of the pits at dimensions of 50×60×600 cm. Therefore, treatments consisted of superabsorbent polymer and Plantbac panels. The experiment was conducted as a split plot design based on randomized complete block, in which soil water suctions levels were considered as main plot and superabsorbent polymers as subplot.The results of the combined effect of both water suctions and superabsorbent polymer showed that the water consumption at these suctions was reduced by prolonging the irrigation intervals to reach higher suctions (more negative). At a soil water suction of 5.0 bars, the water consumption for each seedling was 157 liter, showing 33% decline as compared to the soil containing polymer at the same suction.However, at a suction of 15.0 bars, water consumption in the Plantback declined to 34%. Our results clearly showed that the Plantbac panels could significantly increase the Saxaul growth in different irrigation levels more than that recorded for the control and polymer treatments.

Natural resources, especially rangelands characteristically provide a context for sustainable development of environment worldwide. Recently, rangeland management projects play an important role in preventing pasture degradation and promote their overall status. Community participation is one of the main factors for any successful range management program. Due to the importance of stakeholder participation in rangeland management projects, this study aimed at investigating determinants of stakeholders' participation in rangeland projects of Goltape Dehestan, Saqqez county.Thereby, the study employed descriptive causal comparative research design. The statistical population was consisted of beneficiaries in rural pastures (with high and low participation rate in range management projects). The sample was consisted of 175 rural household heads in Gol Tappeh villages. Structural questionnaires were used to collect data. The questionnaires validity was confirmed by panel of experts and a pilot study was done to assess the reliability. Cronbach's alpha coefficients were between 0.52 and 0.89 for different measures. The results showed that, in active-participant group, perception towards facilitative factors and bottlenecks, environmental awareness and physic-ecological feasibility of rangeland projects and in passive-participant group perception towards facilitative factors and bottlenecks and physic-ecological feasibility were determined the participation in rangeland projects.