In western Iran, mountainous rangelands provide significant resources for livestock productions. Many ecosystems that are of high environmental and economic value are threatened by climate change and social economic pressures. This is especially important for semi-arid rangelands which have a multifunctional system. Quantifying the direct and indirect effects of grazing disturbance on plant biodiversity in the semi-arid mountainous rangelands can provide sight into the appropriate measures to restore degraded rangelands and conserve biodiversity. Here, the effects of different levels of grazing intensity (Light Grazing (LG), Moderate Grazing (MG), and Heavy Grazing (HG)) on plant biodiversity were examined in Nava-mountain rangeland in Kermanshah Province, Western Iran in 2016. The results showed that increasing grazing intensity led to a decrease in species richness, Margalef's richness index, and Shannon-Wiener index (p<0. 05). Stepwise regression analysis was used to investigate the effect of grazing intensity (independent variables) on species diversity and richness (dependent variable). The estimate parameters were significant (p<0. 01) for species richness, Margalef's richness and Shannon-Wiener indices in the different levels of grazing intensity. In overall, grazing intensity explained 47%, 47% and 50% of the variation for species richness, Margalef's richness, and Shannon-Wiener indices, respectively. In addition, species richness and diversity were affected in response to grazing disturbance intensity and reducing grazing pressure can contribute to maintain relatively high species diversity in Nowa-mountain rangeland.

The discharge of total suspended sediments (TSS) and dissolved nutrients from watersheds into receiving waters is a serious problem when natural vegetation is degraded by agriculture or overgrazing. This study was conducted in Soolegan Watershed to investigate land use change and overgrazing effects on phosphorus loss (dissolved & particulate), particle size associated loss of P and effect of time of rainfall on total dissolved P concentration in runoff. Much higher runoff, sediment and nutrient losses observed under cultivated land and HDP (high degraded pasture) than those under MDP (moderately degraded pasture). Contribution of particulate phosphorus exported from micro plot via surface runoff was increased by decreasing plant cover. Largest amount of dissolved phosphorus loss measured in HDP (16.4 mg/m2) and particulate P loss in cultivated land (301.3 mg/m2). Concentration of total dissolved phosphorus (TDP) in runoff was significantly (p<0.05) decreased with time because of increase in runoff volume. Loss of clay associated total phosphorus was 10.9 times greater in cultivated land than that under MDP. Significantly higher amount of labile inorganic P loss, associated with clay and silt particles, founded in cultivated land than that under MDP, which showed the same trend for total P loss by clay and silt particles. The results showed that the degradation of natural plant cover causes an increase in transfer of dissolved P and nutrient rich particles through catchment onto receiving waters. This may lead to phosphorus release into overlaying waters, which make suitable condition for eutrophication.

Soil physical properties have an important role on vegetation growth through affecting the development of root system. The aim of this study was to investigate the trampling effect of livestock grazing on soil physical properties and vegetation cover changes. The experiment was conducted on three range condition sites (Reference, Key and Critical area) with ten frequencies in Hosseinabade Kudistan in 2009. Soil physical characteristics consist of humidity, bulk density, porosity and aggregate stability index. In this study remarked soil cover changes in three mentioned regions. The results showed that soil moisture reduced from reference to critical area. Soil bulk density was the lowest in reference area and the highest in critical area. Reference site had the highest soil porosity while the soil porosity reduced in critical area. However, as the density of grazing increased, soil bulk density increased and soil moisture, soil porosity, aggregate stability index and vegetation cover percent decreased. Bare soil percentage was the highest in critical region. According to the results of this research, the grazing seems caused to major changes in the physical properties of the topsoil. Since the region has high ecological potential, if the intensity of grazing would be in a moderate level, the region soil will be able to compensate the negative aspects of livestock trampling.

The browse vegetation of the Cholistan rangelands is diminishing with the passage of time due to climatic extremities, overgrazing, and human exploitation. Therefore, this study was planned to collect the baseline data about ecology, ethnobotany, and conservation status of browses. A semi-structured questionnaire was designed to record information of plant species from nomadic peoples (85 males, 05 females) and by ecological observations during field visits. In this study, a total of 25 browse species belonging to 17 genera and 12 families were documented, however family status showed that Chenopodiaceae and Mimosaceae were most dominant families. In these rangelands three-soil microhabitats sandunal, interdunal and clayey saline were noted, and each have different species structure and composition. According to life span and life form, all identified species were found as perennials and phanerophytes, respectively. Leaf spectra of Raunkiaerian approach revealed that leptopylls dominated study area, which is an indicator of arid conditions. Phenological observations revealed two flowering seasons, the first season was from February to April and second was from September to November, both were associated to winter and monsoon rains, respectively. Further ethnobotanical observations have divided species into four categories based on their uses i. e., firewood, timber wood, forage and medicinal. The peoples of this area depend on local plants and different parts of plants (bark, leaves, shoots, roots) were used for different treatments. Out of total, 24 species were observed to have forage value that showed potential of this area as rangeland whereas based on grazing response, maximum number of species (40%) were noted as decreasers. According to conservation status, most of browse species have become threatened, followed by endangered, vulnerable, least concerned, and critically endangered, respectively. Results showed current status and potential of browses to apply quick conservation measures with suggestion of further floral investigation in Cholistan rangelands.

Introduction and Objective: The degradation of rangelands in the country has been accelerating both in quantity and quality. This phenomenon not only leads to a reduction in the extent and diversity of plant species but also causes broader environmental impacts such as soil erosion, reduced water resources, and increased natural hazards like floods and desertification. This study aims to investigate and identify the most significant factors affecting rangeland degradation in Fereydan County and to compare the perspectives of experts and local ranchers regarding these factors. Methodology: Initially, degradation factors were identified through a review of literature, field visits, and consultation with natural resource specialists, based on management, economic, social, and natural criteria. Opinions were then gathered from technical experts in natural resources and experienced, informed local ranchers through a five-point Likert scale questionnaire. The validity of the questionnaire was confirmed through expert judgment, and its reliability was assessed using Cronbach's alpha coefficient, which was calculated to be 0. 87 for the expert group and 0. 81 for the local ranchers. The collected data were analyzed using descriptive statistics and the non-parametric Mann–Whitney U test. Results: Among the main criteria, experts identified economic factors as the most significant, with a weighted average of 4. 48, while local ranchers considered managerial factors more influential, with a weighted average of 4. 17. Both groups agreed that natural factors had the least impact on rangeland degradation. Regarding sub-criteria, experts emphasized the economic conditions of livestock holders as the most critical factor (weighted average of 4. 32), whereas local ranchers prioritized livestock and livestock management (weighted average of 3. 97). Among the 30 identified degradation factors, experts ranked (1) the high number of beneficiaries and livestock holders (4. 39), (2) overgrazing (4. 26), and (3) prolonged and repeated grazing (4. 19) as the most destructive. In contrast, local ranchers identified (1) overgrazing (4. 63), (2) drought (4. 53), and (3) high forage prices (4. 50) as the most impactful factors in rangeland degradation in Fereydan. Based on both descriptive statistics and Mann-Whitney test results, economic factors emerged as the primary drivers of rangeland degradation in the region, including issues such as overgrazing, high forage prices, the high number of beneficiaries, and a shortage of protective staff, which are directly and indirectly related to the economic conditions of the region and its livestock holders. Although social factors (such as individual profit-seeking behavior and lack of a sense of ownership) were found to be less directly influential than economic factors, they significantly contribute indirectly by intensifying unsustainable exploitation and weakening collective responsibility. The interaction of these three categories of factors creates a vicious cycle that puts increasing pressure on rangelands. For example, weak management and limited local participation lead to the continuation of unsustainable economic practices, while the lack of institutional support reduces the feasibility of implementing corrective measures. Conclusion: The findings indicate that livestock-related factors, the high number of beneficiaries, and elevated forage prices play a central role in rangeland degradation from the perspective of both experts and local ranchers. While there is general alignment between the two groups regarding the overall causes, differences in prioritization stem from variations in experience, knowledge, and interests. Recognizing these differences, along with understanding the interplay between economic, managerial, and social factors, can serve as a foundation for designing participatory, targeted, and sustainable policies for rangeland conservation.

Under intensive livestock grazing on rangeland ecosystems, balance between facilitative and competitive interactions among plants leads to competition decrement and facilitative relationships' increment. Under such condition, the spatial correlation between nurse plants and understory vegetation would also increase. This spatial correlation leads to increase in survival and diversity of understory vegetation compared to the plants in open area. The aim of this study was to evaluate the role of nurse species (sponsor) in the preservation of understory diversity in three different grazing areas of Sar Aliabad summer pastures. Sampling was conducted at three different grazing areas including overgrazed, open grazed and exclosure sites. To this purpose, forty five 1m2 plots of were randomly-systematically establishment in each area. Half of the plots were established within the open spaces among the bushes, whereas, the remaining plots were assigned to the nurse plants, and number of plants within the plots was recorded. Thereafter, Shannon indices were used to evaluate the plant diversity within and under the nurse plants. Results indicated that Shannon diversity index for understory vegetation in grazing areas was higher than those of plants in open spaces. Diversity increased by reduction in the grazing intensity and was higher in moderate grazing area than two other grazing areas.

The study of soil C dynamics and factors controlling this important soil process in rangeland ecosystems mayprovide an insight into understanding and evaluating changes in the global C cycle. The primary objective of this study was to quantity the effects of pasture management (i.e., grazing, controlled grazing and ungrazing) on soil C levels and mineralization in three natural rangeland sites of Chaharmahal Va Bakhtiyari province. Three range management regimes including: (a) long-term ungrazed, (b) controlled grazed and (c) free (over) grazed in close vicinity were selected at three sites including SabzKouh (protected from grazing for 18 years), Boroujen (protected from grazing for 23 years) and Sheida (protected from grazing for 2 years). Soil samples were collected from 0-15 cm depth and organic C, total N and C mineralization were measured using standard methods. Results show that SabzKouh and Sheida sites had the highest (14.6 mg g-1) and the lowest (4.80 mg g-1) soil organic C contents, respectively. Soil total N and organic C contents at SabzKouh were significantly higher when compared to other sites, probably due to more rainfall and humid climate. The effect of range managementon soil C mineralization was evident at two of the three sites. Results indicate that the exclusion of grazinganimals resulted in an increase in soil C mineralization at SabzKouh and Boroujen sites, probably through the addition of plant residues and animal excrements to the soil. However, ungrazed management did not improve plant cover and soil properties in Sheida area, due likely to dry climate conditions, less biomass production and the history of cultivation and agricultural uses. It is, therefore, concluded that the effect of grazing on soil Cmineralization depends primarily upon the plant community and climatic conditions and also upon the type of rangeland management and even land use history involved.

Interactions between two plants affect their survival and establishment, therefore, the knowledge of these interactions can be useful for maintenance of the species, and rangelands management improvement. Since nurse species can be important factor to the rangeland plants population, they can be used in exploited areas. Thus, the role of nurse species was studied on palatable species of Sar-Aliabad (Gorgan province) rangeland, under three grazing conditions (overgrazing, open grazing and exclosure sites). In the first stage, in order to determine different grazing area around the grazing zone, 1´1m2 plots were systematically used in the four main directions. Then in each site, 40 plots have been systematic-randomly established and basal number of species per plots was recorded. The nurse species and related species were determined in each grazing areas and relationship between species have been measured in each site. Results indicated that Festuca ovina in all three grazing areas had positive and significant correlation with Astragalus verus. The correlation in overgrazing area was higher than exclosure and open-grazed areas. Therefore regarding that all rangelands in Iran have poor to medium condition, determination of nurse species and depended species can be useful for rangeland improvement programs and ecological management.

Risk assessment of soil erosion, one of the most important land degradation problems worldwide, is very essential for land and water resources management, and development of soil conservation methods. In the present study, the temporal changes of soil erosion risk were assessed from 1987 to 2010, based on the Revised Universal Soil Loss Equation (RUSLE) using Remote Sensing (RS) and Geographic Information Systems (GIS) for the Navrood Watershed, Iran, with an area of 270 km2. Two Landsat satellite imageries obtained in 1987 and 2010 were used to assess the changes in vegetation cover during this period, and to obtain the Cover factor (C) of RUSLE. Rainfall and soil texture data and a digital elevation model were used to calculate the rest of RUSLE factors, which were taken as constant for the study period. The results showed that the average annual soil loss over the watershed ranged from 0 to 1, 056 t ha-1 y-1 (Cumulative percentage>99.9%). The area mapped as very high erosion risk (>100 t ha-1 y-1) increased from 10% in 1987 to 12% in 2010, and the area of the next risk class (51-100 t ha-1 y-1) increased from 8 to 9%. These changes cover an area of about 800 ha in the watershed, in which erosion risk has been doubled or tripled in the last 23 years. Forest clearing and rangeland overgrazing were identified as the most important reasons for the increase in erosion risk.