فصلنامه تحقیقات مرتع و بیابان ایران
سال بیست و هشتم شماره 3 (پیاپی 84، پاییز 1400)

Awareness of the extent and impact of vegetation from livestock grazing disorders can be a solution to develop rangeland ecosystem management strategies to achieve sustainability and continuous production in these ecosystems. In this study, the production of aerial and underground organs of grazable livestock species in the southeastern rangelands of Sabalan under the influence of different grazing intensities and distance from the village as the focus of the crisis was investigated. In addition, the development and evaluation of ANFIS model was presented in order to predict the production of aerial and underground organs of food species and compare the results with the regression model. For evaluation of regression and ANFIS models the Root Mean Square Error (RMSE) and correlation coefficient (R2) were used. The results showed that different grazing intensities, distance from village and interaction between them were significant effect on the production of aerial and underground organs of palatability species at (p≤0.01). Also, with increasing grazing intensity, the production of aerial and underground organs of these species decreased. The results of ANFIS section showed that in low grazing intensity and distance of about 400 meters, the highest amount of production of palatable species is observed. The lowest production of these species is predicted to be close to the village (200 meters). Moreover, the highest amount of underground biomass at farther distances (600 meter) and lowest amount of that was observed at 200 meter. In addition, ANFIS model with higher accuracy (R2 = 0.98 and R2 = 0.95) and lower error (RMSE = 0.9792 and RMSE = 1.168) than less accurate regression model (R2 = 0.92 and R2 0.77) which also had more errors (RMSE = 2.2835 and RMSE = 3.8954), predicted the production of aerial and underground organs, respectively.

Soil and plants in natural ecosystems are always interacting with each other. The different structure and characteristics of plant species in an area in the long term affect environmental variables, especially on the soil. The aim of this study was to investigate the effect of two different plant species, Astragalus myriacanthus and Acantholimon spinosum, on some soil chemical properties in the different spatial locations. Soil sampling in early fall 2018 by randomly selecting 20 replicates (10 individuals of each species) from four locations (upward slope edge, downward slope edge, center and outside (as control)) in sycamore rangelands Naz, Yazd province, was done and a total of 80 soil samples were collected. Then, chemical properties of the soil including pH, EC, total organic matter (TOM), particulate organic matter (POM) and total nitrogen (TN) were measured in the laboratory. The effect of plant presence on soil properties showed that the parameters of organic matter (mean 1.66%), total nitrogen (mean 0.22%), electrical conductivity (mean 368.97 Ms / cm) and POM (with an average of 1.28%) in beneath A. myriacanthus significantly more than the soil outside the floor (with averages of 0.92%, 0.13%, Ms / cm 139.5, 58, respectively (P <0.05). TN and POM in upslope edge were significantly higher than other edges. In A. spinosum, there were no significsnt differences of TOM (1.77%), TN (0.23%), EC (215.46 Ms/cm) and pH (7.97) in beneath with outside the canopy. While the POM with an average of 1.49% had the highest amount under the canopy relative to the outside soil as well as other sampling sides. In general, this study expresses the different role of different cushion plants on the chemical and qualitative characteristics of the soil, which by recognizing this role can help to improve, develop and maintain their habitats.

The aim of this study was to investigate the effect of Sufivand-manganese mine (located in Harsin city of Kermanshah province), on some soil characteristics, plant growth and some physiological traits of yellow milk-vetch (Astragalus parrowianus). Soil and plant samples of natural rangeland were taken in May around Sufivand mine at different distances namely in  the 100,500.1000,1500 and 2000 meters far from the mine respectively The statistical design of this project was performed based on a systematic random methodology in the five concentric circles around the Manganese mine. Six samples of soil and Astaragalus plant outside of manganese mine boundary (was not affected by mine) with the same edaphic and topographic conditions were sampled as a control treatment. The results of this project indicated that measured some physiological properties and plant growth were significantly affected by the distance from the Manganese mine. Hence, the maximum rate of root weight to canopy weight (0.85), transfer factor (1.9),    root density factor (4) and proline content (0.8 μmol / g) were significantly observed at (p 0.05) compared to the control treatment at a distance of 100 meters from the mine. The minimum stem length (12 cm), total nitrogen content (3%), essential oil content (0.2%), catalase activity (0.45 Units/mg) and peroxidase activity (0.2 Units/mg) at 100 meters distance from the mine were significantly different from the control at (p 0.05). It is concluded that the closer distance to the mine the more hazard of manganese to the Rangeland plants.

In order to investigate the preference value of plants, this study was conducted in a rangeland in Hormozgan province. To determine the preference value in this region, two methods of timing, production and consumption of plant species were used using Tali goats during the months of grazing season (January to May) for 4 years (2007-2009). The results of analysis of variance for the preference value in the timing method (using a video camera) showed that there is a significant difference in terms of forage consumption time between species. So that Alhagi persarum with the highest mean (43.9%) along with Aeluropus lagopoides with an average (31.5%) were in a class statistically, followed by Desmostachya bipinnata, Atriplex leucoclada, Halocnemum strobilaceum, Suaeda fruticosa, Tamarix mascatensis and annuals are 6.6%, 5.4%, 3.6%, 2.8%, 2.3% and 3.7%, respectively. Finally, Lycium shawii plant with the average of 0.2% has the lowest class. There was also a significant difference in the interaction factor of year and species, so that Alhagi persarum in the second year (2008) was ranked first with 68.7%. The results of analysis of variance for species exploitation percentage also showed a significant difference between the study years. The first, third and fourth years were in one group and the second year with the lowest percentage of exploitation (36.4%) was in the second group. The highest percentage of exploitation belonged to Aeluropus lagopoides with 54.3% in 2009. According to the preference value index classification, Aeluropus lagopoides, Atriplex leucoclada and Alhagi persarum were among the moderately palatable species (class II) and Halocnemum strobilaceum and Desmostachya bipinnata were among the almost non-palatable species (class III).

The present study was conducted to investigate the differences between several remote sensing indices, four different plot sizes and two different sampling methods to estimate the percentage of plant cover and production in three plant communities in 2013. Ground sampling was performed in three communities with different dominant vegetation in two forms of six and three quadrats. Four different dimensions of the quadrats were used nested to estimate production and coverage percentage. Sampling was performed in each community within 30 pixels along three transects with different heights (sampling method and testing were performed according to the researcher opinion). Dominant plant density was measured by counting the bases per plot, plant cover percentage as an estimate and production in the form of double sampling in relation to cover percentage. The results showed that with increasing plot area, the degree of correlation of plant indexes of Landsat image and their significance in relation to production and percentage of plant cover will increase. But this increase in community 2 is more dramatic in most respects with predominantly shrubs. As in this community, most of the studied indicators in 3 × 3 plot have a correlation and a reliable model, and in the three sizes of 1×1, 2×1 and 2×2 plots, the resulting models are not valid enough and have high RMSE. In community one with dominant broadleaf plants, only the model obtained in 1×1 plot and in community two with dominant plants, the model obtained in 1×1 and 1×2 plots are not statistically valid, although sometimes they have a significant correlation. The results of two different models are statistically different in communites 1 and 3 and there was no significant difference between them in community 2. According to the results of the study of indicators in terms of correlation and model validity, the two indicators NDVI and CTVI can be used in community 1, NDVI and TSAVI1 in community 2 and NDVI, NRVI and TSAVI1 in community 3 recommended for estimating production and percentage of plant cover using satellite images.

Halophytes are one of the essential parts of haloculture that do not compete for the occupation of lands and freshwater resources. Salicornia persica Akhani grows naturally in the southern coastal and desert areas of Iran. This study was conducted to evaluate the effect of two irrigation water quality treatments (seawater and shrimp farm waste-water with electrical conductivity of 64.5 and 66.4 dS m-1 m, respectively) and potassium sulfate fertilizer treatment (with three levels of 0, 100 and 200 kg ha-1) on the amount of forage produced (yield) and height of this plant was investigated in factorial experiment based on randomized complete blocks. The results showed that the yield of Salicornia dry forage under irrigation with seawater and shrimp field waste-water irrigation was 1136.92 and 740.8 kg ha-1, respectively, with significant differences. Investigation of the interaction effects of irrigation treatment (two levels) and potassium sulfate fertilizer (three levels) showed that the highest forage production yield was related to the treatment of 100 kg ha-1 of potassium sulfate fertilizer irrigated with seawater at the rate of 1538.8 kg ha-1 of dry forage .There was no significant difference between plant height related to irrigation treatments and potassium fertilizer application. The results showed that the production of Salicornia under irrigation treatments with seawater and shrimp farm waste-water is possible and consumption of 100 kg ha-1 of potassium sulfate increases yield. Further research was proposed to improve the production potential of this saline plant through agricultural operations and selection of superior germplasms using seawater and shrimp farm waste-water.

Knowing the potential of ecosystems in providing services is essential for designing management programs. Therefore, a study was done to investigate the impact of livestock grazing on ecosystem service pollination in Malah Shoreh and Gorgo rangelands in Kohgiluyeh and Boyer-Ahmad Province. For this purpose, 100 quadrats were planted in the grazing area and the percentage of canopy cover of the species in the plots was estimated. Plant species attractiveness for honeybees were determined as an indicator of ecosystem's potential in providing ecosystem service pollination. The results showed that grazing had caused a significant decrease in the abundance of species with high and medium attractiveness for honeybees (p <0.05). Pearson's correlation analysis showed that there is a positive correlation between plant species life’ forb and high and medium attractiveness for honeybees (p <0.05). Among the studied vegetative forms, perennial grasses and shrubs, which are less important in providing pollination function than perennial and annual forbes, have been severely reduced in the grazing area. In general, livestock grazing has reduced ecosystem service pollination in the study area. Given the importance of ecosystem service pollination in the sustainability of natural ecosystems, it is crucial to pay attention to the conservation of plant species with high attractiveness for pollinators in grazing management.

In order to study of forage quantity and quality traits of eleven accessions of two varieties (sub species) of Elymus hispidus var. hispidus and Elymus hispidus var. villosus and six accessions of Agropyron cristatum were carried out in two separate experiments using randomized complete block design with three replications in Khorasan-e-razavi Agricultural and Natural Resources Research and Education Center. The seeds of the above accessions were sown in greenhouse conditions at a temperature of 20 ±2 ° C and 5 of them were planted in each plastic pot and after full establishment, the seedlings were transferred to the main soil. In order to, fully establish the seedlings in the main field and ensure the purity of the accessions, the first year of the project was considered as the year of establishment. The results of comparison between the varieties of E. hispidus showed that the villosus variety had higher forage yield, number of spikes and spike length compared to hispidus. In contrast, the percentage of plant establishment was higher in hispidus variety. In terms of forage quality, there are no difference between the E. hispidus accessions. In villosus variety, Chahar-Tagh accession due to high total dry matter (DM) yield (7732 kg ha-1), high dry matter digestibility (DMD) (43.6%), high soluble carbohydrates (8.8%) and consequently low acid detergent fiber (43.7%) was superior to other accession. In species A.cristatum 1727 accession had the lowest height, the lowest forage yield and the highest number of spikes. Among the accessions of A. cristatum, the highest and lowest annual dry matter yield of 12974 and 5692 kg ha-1 per year was achieved in 208 and 1727 accessions, respectively. Accessions 208 originating in Isfahan also had a significant percentage of digestibility and protein. In general, the results of this study showed that the accessions of the villosus variety as well as the 208 accession were superior to other accessions.

In current research, some soil properties and growth of camelthorn (Alhagi maurorum Medik.) were monitored in saline lands in Yazd Province during 2019-2020 and accordingly, the ability of this species was determined for growing in the saline lands. For this purpose, seven rangelands in Yazd consisted of Bafgh, Javadieh, Bahabad, Jolgeh, Ardakan, Aghda and Abarkooh were selected, in which Alhagi was dominant vegetation. Salinity of saturated extract (ECe) and pH of soil, salinity and pH of water, fresh and dry weight were measured by sampling and apparent soil salinity (ECa) was assessed by electromagnetic induction device (EM38). The results showed that regression coefficients (R2) of estimating soil salinity using EM38 device in different regions were accepted and varied between 0.52-0.86. Soil salinity levels varied over the surveyed lands from 2.17 g salt/kg soil in Aghda to 226.5 g salt/kg soil in Ardakan for 0-30 cm soil depth and from 0.4 g salt/kg soil in Bafgh to 118.3 g salt/kg soil in Ardakan for 30-60 cm soil depth. The maximum production of ryegrass, equal to 25 tons ha-1 of fresh weight and 7 tons ha-1 of dry weight, was observed in Bafgh with water salinity of 12 dS m-1 and soil salinity of 11 g kg-1. On average, the highest production was observed in Bafgh, Bahabad, Abarkooh, Aqda and Ardakan, respectively, which was almost consistent with changes in soil salinity and acidity. It seems that Alhagi has high tolerance to water and soil salinity, however, is sensitive to soil pH. The use of EM38 device to evaluate soil salinity in lands with camelthorn cover of Yazd province was reasonably accurate, and is recommended for monitoring soil salinity of other rangelands, but calibration in each area and for each soil depth separately is necessary.

In the present study, the existing land uses in the Minab plain were simulated using the CA-Markov combined method. For this purpose, land use maps for the years 2000, 2010 and 2020 were generated using Landsat satellite images using the maximum probability classification method and after evaluating the model, the land use map for 2030 and 2040 was predicted using the combined CA-Markov method. Analysis of land use change patterns in Minab plain showed that during the statistical period 2000-2020 in the level of land uses in this area has changed significantly so that during this 20-year period the area of agricultural land use, urban and man-made areas, saline lands and rangelands and barren lands respectively from 38.91, 25.99, 20.09 and 15 % in 2000 to 40.75, 40.02, 12.44 and 6.80 percent in 2020. Evaluation of the model using kappa index above 90% indicates the high accuracy of the model for predicting land uses. Prediction of changes in 2030 and 2040 show that the use of agricultural lands and urban areas and man-made are increasing at a rate of 0.05 and 0.39 %, respectively, which are advancing from the east of the plain to the west; Meanwhile, the uses of saline areas, rangelands and barren lands are decreasing at a rate of 0.44%, which is more evident in the west and northwest of this plain. Finally, one of the most important executive strategies of planners and officials to prevent land use change and ultimately land degradation in this area, can be to improve the cultivation pattern, new irrigation methods, nourish the bed of this plain and maintain and restore native vegetation.

By evaluating land use change and land cover, it is possible to plan and land manage to reduce the impact of alteration and degradation of exploitations. The purpose of this study was to evaluate land use changes in Ardabil province between 1987 and 2015 using Thematic Mapper (TM) sensor of Landsat 5 and Operational Land Imager (OLI) sensor of Landsat 8 satellite images. Firstly, the efficiency of the object-based classification method was evaluated using ground control points, error matrix, and comparing total accuracy and kappa coefficients for the resulting maps. Total accuracy and Kappa coefficients for 1987 were 82.3% and 0.70, and 2015 were 94% and 0.90, respectively. Change detection results showed that from 1987 to 2015, rangelands decreased by 4.2%, equivalent to 75039.3 hectares and forests decreased by 0.5%, equivalent to 9393.7 hectares compared to the total province area and irrigation farming increased by 3.1%, equivalent to 55276.8 hectares, residential areas increased by 0.8%, equivalent to 14989.7 hectares and dry farming increased by 0.7%, equivalent to 12632.4 hectares compared to the total province area. The most significant changes that occurred from 1987 to 2015 were the conversion of rangelands to dry farming with 13.8%, equivalent to 141794.2 hectares and irrigation farming lands with 4.8%, equivalent to 49836.9 hectares of rangelands, irrigation farming to dry farming with 7.7%, equivalent to 11464.8 hectares and forests to rangelands with 6.1%, equivalent to 1059.9 hectares which indicate that the requirement of a serious revision of the management policies.

Understanding the ecological characteristics of plant species and how they respond to environmental factors provides the information needed to manage vegetation and restore rangeland ecosystems. The aim of this study was to determine the environmental factors affecting the habitat of Krascheninnikovia ceratoides (L.) species and its response to changes in ecological factors in the rangelands of Isfahan province. Accordingly, canopy cover and density of K.ceratoides and the associated species were measured in 19 ecological sites using random systematic sampling method. In each site, climate, physiography and soil factors were identified. Canonical Correspondence Analysis (CCA) and Generalized Additive Models (GAM) using CANOC4.5 software were used to investigate the vegetation relationship with environmental factors. The results showed that the response pattern of K. ceratoides along the gradient of absorbable potassium follows the incremental model. Conversely, the response of this species along the gradient of sand percentage, average annual temperature and rock and gravel percentage has followed a decreasing model and with increasing these factors, the percentage of canopy cover has decreased. The response pattern of K. ceratoides along the changes of the amount of absorbed phosphorus, the percentage of gypsum and the altitude of the sea, follows the bell model (Unimodal), and its optimal growth limit for these factors is 10 mg kg-1, 6.4% and and 2250 meters. The study of K. ceratoides species response along the gradient of topographic, soil and climate factors provided valuable information to determine the ecological needs of this species that can be considered in vegetation management and rangeland improvement operations in similar areas.

Today, global warming and climate change are considered to be the greatest challenge of human life that has overshadowed other environmental challenges. In this study, it has been attempted to detect climate change phenomena in Yazd by monitoring the trend of heat wave changes and its relation to temperature anomaly. For this purpose, daily temperature data for the time period (1960– 2017) were used. Finally, the characteristics of heat waves such as the number of occurrences of heat waves, frequency of days with heat waves, heat wave continuity, magnitude and intensity of heat waves and average heat wave (hottest day of heat wave) using ClimPACT software in programming environment R 2.10 were calculated. Heat waves are the result of incremental temperature changes. Therefore, temperature anomaly of Yazd station was extracted and compared with the temperature anomaly of the Land's surface. The relationship between heat wave indices and temperature anomalies was investigated. The results showed that the highest number of heat wave events occurred in 2010 and 2016. The number of days associated with the hot wave has increased significantly, with 47 and 42 days in 2010 and 2016, respectively. An increasing trend in the continuity and intensity of heat waves was also observed. The longest continuation for 2013 was estimated to be 13 days. The findings also show that in the last two decades the magnitude of the heat wave has reached more than 31 ° C. Investigation of the relationship between all indices related to heat wave and Yazd temperature anomaly showed good correlation and coefficient of explanation of temperature anomaly and frequency of days with heat wave was higher than other indices and its R2 was approximately 0.6108. In general, the results indicate the intensification, continuity and intensity of heat waves in Yazd city, which can indicate the occurrence of climate change, especially in the last two decades in this region of the country as a representative of the arid regions. Due to the increasing temperature in the coming years on the frequency, intensity and continuity of these waves will increase, knowing how heat waves are processed can help managers and planners make risk management decisions about energy efficiency.

Ferula assa-foiteda L., as one of the most important range plants in northeastern Iran, plays an important role in soil conservation and the economy of rangeland stockholder. However, misuse and destruction of its habitats are among the factors threatening this natural capital. This study was conducted to identify potential habitats of this species in the two provinces of Khorasan Razavi and North Khorasan, which can be a step towards to facilitate and develop replanting and rehabilitation operations of this species. Spatial data of the presence of this species with a pixel size of 1100 × 1100 m were used as actual suitable places for its growth and layers of environmental information such as climate, soil, geology and physiography were used as predictor variables. First, in Biomaper Version 4, the correlation of prediction variables was examined and independent variables were selected. The potential habitat areas extracted from the species distribution model mapped with the Maxent 3.3 software. The results showed that the used model had good accuracy and reached to AUC of 0.97. In terms of significance, the study of input variables to the model using the Jackknife test showed that, respectively, land unit components, seasonal temperature, geological formation, dominant land slope, habitat height and daily average temperature are suitable for the potential habitat of Ferula assa-foiteda L. species in the level of the study area is of the utmost importance. The results of this study can be used to identify the ecological needs of the species (Ferula assa-foiteda L.) and to develop and rehabilitate their habitats.

The study of vegetation and the measurement of diversity indices are suitable tools for studying the status of forests and rangelands and evaluating them. The purpose of this study is to evaluate the trend of vegetation changes during four consecutive years and in two seasons in the Bagan region. For this purpose, 5 transects of 100 meters with distances of 50 meters in the study area were considered systematically randomly. A total of 30 plots of one fixed square meter were installed along the transects. In two growing seasons, spring and fall, from 2017 to 2020, the type and percentage of cover of native species were harvested. Dominance, uniformity and diversity of Simpson, Shannon and Hill species were measured using PAST and R software. The results of one-way analysis of variance (ANOVA) showed that there is a significant difference between the mean of dominance, Shannon and Simpson indices, percentage of cover, and the number of species in the spring of different harvest years. In fall, except for the dominance index in other indices during July 2019 compared to 2018, there was a significant difference. From the results, it can be concluded that despite the return of some annual or short-lived species such as Bienertia cycloptera Bunge and Salsola jordanicola Eig. following irrigation of cultivated seedlings and rainfall, the study area is still sensitive and fragile and needs to be managed and confined until proper rehabilitation.