نشریه مرتع و آبخیزداری
سال هفتاد و پنجم شماره 1 (بهار 1401)

Plain ecosystem is highly vulnerable to environmental changes, and drought is the most famous ecosystem change driver that is difficult to identify after its occurrence. In this research, to study the slope of vegetation changes against drought, the NDVI index of MODIS images and the SPI index from 2001 to 2016 were used and the map of vegetation changes against drought with five drought stress classes included very low classes, Low, moderate, high and very high, so that a suitable assessment of the drought can be made at specified time scales. The results of slope pattern of spatial change of vegetation against drought showed that across the plain vegetation changes have declined, and from east to west of Qazvin plain, the slope of vegetation changes and land susceptibility to drought have been reduced. So that the most percentage of area in a one-month drought related to the drought class is very low, but in droughts of 3, 6, 9, 12, 24 and 48 months, the highest percent of the area belonged to moderate and high drought classes. The results of this study, the determination of the level of vegetation changes in against drought in the past years and prediction of these changes in the future years, can be used in the planning and optimal use of resources, control changes in the future.

Ferula foetida is one of the important medicinal plants in the steppe rangelands of Iran. Applying effective methods for its establishment can be useful for reviving the ecosystems of arid areas and the economy of its indigenous people. Due to the fact that drought stress is one of the main limitations in the establishment of plants in arid and semi-arid regions, in this study the effects of various treatments were studied on seed germination and establishment of Ferula foetida seedlings, in the Kakhk Twin Watersheds, located in the south of Khorasan Razavi province, Gonabad city. Experiment included some soil moisture conservation treatments (stone shelter, superabsorbent, superabsorbent + stone shelter or control) and seed treatments (prechilling or control), with 30 replicates for each treatment. Superabsorbent + sand shelters and sand shelters alone, reduced temperature and increased soil moisture. Moisture conservation treatments led to higher number of seedling emergence and survival and higher seedling height than those of control. Among the moisture conservation treatments, superabsorbent + stone shelter performed better, especially for the prechilled seedlings. According to the our results, superabsorbents and stone shelters can improve the production and productivity of Ferula foetida, especially during the drought times. We also suggest prechilling treatments to overcome the dormancy of Ferula foetida seeds.

The use of biochar as a soil amendment is one of the new methods to improve soil properties and increase plant yield. In this study, in order to evaluate the effect of adding natural biochar on soil properties and yield of Pamirian winterfat (Eurotia ceratoides) plant, an experiment in a completely randomized design were performed with 11 treatments by different levels of biochar (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10% by weight) and three replications in greenhouse conditions. After the end of the growing season, some physical and chemical properties of the soil (pH, EC, organic matter (%), lime, bulk deisty, particle density, and porosity percentage), germination percentage, and yield of E. ceratoides were measured. In all the studied traits of the soil (except for the particle density), and the characteristics of the E. ceratoides plant, the statistical difference between the various levels of biochar was significant (a = 0.01). Adding different levels of biochar increased pH, ECy, soil porosity percentage, soil organic matter, whereas decrased bulk density, lime percentage, clay percentage, sand, and silt.

The aim of this study is to prioritize effective factors, landslide susceptibility zonation assessment using maximum entropy (MaxEnt) and dempster shafer models in Doab Samsami watershed of Chaharmahal and Bakhtiari province. For this purpose, 15 factor maps affecting landslide occurrence as independent variables and landslide distribution map as a dependent variable were prepared and weighted using frequency ratio index (FR) and landslide distribution map in the environment ArcGIS® 10.8 . In order to implementation and validation of models, landslide distribution data were randomly divided into two categories of training and test data in the proportion of 70 and 30%, respectively. Maximum Entropy (MAXENT) and Dempster Shaffer models are performed and landslide susceptibility zonation maps are prepared and each model is divided into five very low to very high. In order to evaluate the classification accuracy and validation of the models, the frequency ratio and seed cell area index (FR&SCAI) and the area under receiver characteristic curve (AUC-ROC) were used, respectively. According to the results of the maximum entropy model, annual precipitation factors, lithology, distance to road and drainage land use are important in landslide occurrence, respectively. According to landslide susceptibility zonation maps in both models, more than 50% of landslides occurred in high and very high susceptibility categories. Finally, the validation results of the models showed that the Demester shafer model with AUC-ROC index of 0.95 and classification accuracy with higher FR & SCAI index, greater efficiency and desirability for zoning, modeling and landslide prediction in the study area.

Because ofthe conflicts of interest, the interaction of beneficiaries and natural resource experts inIran hasbeen challenged.This area was studied asthetarget, due totheechologic andsocial condition andconsideringthe existing conflicts. In this study, legal, managerial, exploitation, and social components were examined from the perspectives of both experts and beneficiaries. 188 questionnaires were completed with the Snowball Method. The validity of the main variables of questionnaire was greater than 0.7. The Mann-Whitney U-test was used to compare differences between two groups. The results show that in addition to the natural resources conflict in the whole region, in terms of perspective, there is a significant difference between the factors affecting the conflict between the local community and government experts. The most important components for increasing the conflict in this region from the perspective ofstakeholders are the lack oflaws, the presence of non-natives inrangelands and forests, the low presence of women in this natural resources field and according to the experts, lack of land-use conversion, and level of awareness of stakeholders. Land grabbing, Coaling and understory tillage are the most challenging issues in the west of Gilan province.From the managerial point of view, both groups have declared that the most effective way to reduce the conflict is the confinement of forests and pastures, but the participatory management issues was not accepted according to the two groups’ viewpoints. Effective presence of experts in the field, recognizing the livelihood potentials of the region, and encouraging and educating people to know alternative jobs are suitable ways to reduce conflict.

The purpose of this research was investigation of soil physicochemical and particle distribution in three agricultures, rangeland and forest park land use in two surface (0-15 cm) and subsurface (15-30 cm) depths in Oshtorninan city on the Lorestan province. Soil sampling was done in 45 points in three land use. Some soil physico-chemical properties were determined in laboratory. This experiment was arranged in a factorial manner. The results showed that the change of rangeland use to agriculture has resulted in a decrease in clay content, cation exchange capacity, soil carbon, nitrogen and soil particle size. Changing the land use of pasture to forest park has led to an increase in the amount of clay, silt and soil acidity. Mean comparison showed that there was no significant difference between bulk density and electrical conductivity in the three land uses (p ≤ 0.01). Analysis of the data showed that the soil cation exchange capacity, organic carbon, clay and silt content in three land uses and two depths were significantly different (p ≤ 0.01). Land use factor also showed a significant different on soil sand and lime percentage (p ≤ 0.01). The soil granulation did not change with the conversion of the rangeland in to a forest. Increased organic carbon and soil clay content could be the reason for this. In general, land use change from pasture to agriculture similar to other research is unfavorable, but land use change to forest park has improved clay content, cation exchange capacity and soil organic carbon.

Due to the importance of vegetation cover in these areas, the aim of this study was to investigate the effect of drought, on vegetation of HablehRood watershed.Initially, NDVI index obtained from MODIS sensor was used to study vegetation cover and then SPI index based on rainfall data of two basins in two arid and semi-humid climates was used for drought assessment (2001-2018) using image processing methods. The results showed that during this 18-year period, 53% of the region had droughts on average. Also during the period 2001-2003, drought was more severe than other periods (2003-2018). In addition, the highest vegetation index occurred in 2005, indicating that vegetation was affected by rainfall fluctuations in the region. The correlation matrix between the three indices indicated that NDVI had the same correlation with SPI and annual rainfall. The results of this correlation in dry and semi-humid climates showed that the correlation was 0.38 and 0.25, respectively. These results indicate that this relationship is positive and robust in different climates of a region؟. On the other hand, drought class is mainly located in dry and semi-humid climates, with 55.55% and 50% in relatively normal drought class, respectively. Based on the above, it can be concluded that using remote sensing data can monitor the response of semi-humid and dry arid ecosystems to climate change. The study also showed that arid and semi-arid regions are highly susceptible to climate change and human anomalies. Therefore, the destruction of these lands will have many environmental and economic consequences.

The dynamics of human activities threaten the sustainability of global life-support systems. Analyze of anthropogenic transformation data play a central role in environmental problems evaluation. This study aims to analyze human activities in watershed. Studies and analyzes revealed that the anthropogenic transformation variables include the type, intensity and trend. Spatial and temporal patterns of the type of activity (land use), intensity and human intervention were studied using satellite images and field observation. The classification and land use map were done in two phases: The functional phase included the main land uses including agriculture, rangeland, urban and water resources, and the activity phase included ten types of land use. The study of the human interventions intensity in land use units was carried out based on the temporal extension of agricultural land development (agricultural land use), the rangeland condition assessment (rangeland land use) and the area extent of under influence (urban area and water resources). The results of land use studies identified that Rangeland lands cover 77.2 percent and agriculture, urban area and water resources land uses accounted for 21.5, 1.1 and 0.2 percent, respectively. The results of the intervention trend indicated that the trend continues from normal conditions to the replacement by technogenous structures. This trend has revealed growth of agricultural activity in rangeland and as well as the tremendous loss in cropland in uneven urban and industrial growth. The results of the study show the compatibility between the three variables of anthropogenic transformation; ie, the type, intensity and trend.

Prevention is the most appropriate way to deal with natural hazards. And resilience means maintaining the structure and function of the socio-ecological system in the face of unexpected events, one of the important branches of prevention. Chaharmahal va Bakhtiari province, due to its specific geographical location, faces numerous environmental hazards annually. Therefore, in this study, the status of resilience in the face of environmental hazards in the governing system of this province was investigated. AHP method was used for this purpose. In the AHP process, based on the pairwise comparison of criteria and sub-criteria, the degree of association between both criteria and sub-criteria is compared and scores between 1-9 are assigned. The research data was analyzed based on Delphi method and hierarchical decision making process. The results showed that according to expert’s evaluation of resilience of socio-ecological systems of Chaharmahal va Bakhtiari province against climate change (4.51), drought (2.09) and soil erosion (2.02) were ranked first to third respectively. Because of this, climate change has attracted the attention of experts who have shifted the rainfall to snow ratio over the past two decades. So that from 70% snow and 30% rain, to 70% rain and 30% snow. However, much of the economic activity and livelihoods in the province depend on snow reserves.

Fire is one of the important ecological factors that affect the dynamics of rangeland vegetation. In recent decades, the incidence of wildfires in semi-steppe rangelands has increased significantly, challenging the adaptive capacity of plants for post-fire regeneration. In the present study, the germination response of eight annual and perennial herbaceous species of semi-steppe rangelands of Chaharmahal va Bakhtiari province to fire products treatments including heat (60, 80 and 100° C), smoke, ash, and the combined effect of heat and smoke treatments were investigated. Also, percentage cover change of studied species, one year after the fire were measured in the field. The results showed that the germination of seeds of eight studied plant species showed a significant positive or negative reaction to at least one of the fire product treatments. Combined treatment of smoke and 60° C caused a significant increase in the mean germination percentage of Heteranthelium piliferum. This treatment also significantly reduced the mean germination time of Cousinia cylindracea. Ash treatment also increased the mean germination percentage of Alyssum linifolium and Stachys lavandulifolia. Vegetation sampling results also showed that among the eight species studied, H. piliferum and Taeniatherum crinitum were fire adapted and six species were tolerant. The results of this study can be used as a potential factor to understand the dynamics of vegetation and restoration of degraded rangelands.