نشریه مدیریت اکوسیستم های طبیعی
سال دوم شماره 2 (پیاپی 3، تابستان 1401)

Natural and semi-natural ecosystems have many direct and indirect services. By evaluating the economic value of their various services and functions can be a step towards effective management and maintaining. The sheikh-mousa rangeland ecosystem in Babol city, in the past few decades, experienced harsh human interferences including construction and intense livestock grazing that has caused. The services and features of this important ecosystem are under extinction threat. Therefore, the current study was investigated the economic value of forage production as a production function, and waste treatment and soil formation as regulation actions in the sheikh-mousa rangeland ecosystem. In the current study, the valuation of services for the year 2017 is done by Replacement cost and market price methods. The results showed that the total regulation value (waste treatment and soil formation) and production value are 2615 & 8348 million Rials (62261.06 & 198767.75$) per year for the total area of sheik-mousa rangeland ecosystem, respectively. Also, the value in each hectare of both regulation and production functions was estimated 251269.7 Rials (6$) and 802176 Rials (19$) respectively. The results show that the regulatory functions have a high economic value as well as the production function of the rangeland ecosystem. Therefore, it is suggested to prioritize the plans and pay attention to them in order to reduce the environmental costs and the sustainability of this ecosystem.

Detection of climate parameters indicates that climate change has begun in Iran and it is necessary to identify the potential habitat of the indicator species, present and future years, under climate warning models. In this regard, it should be examined whether the increase in incident temperature in the country, will have a positive effect on the presence of species in the habitats of the distribution site, or a negative effect? For this purpose, the current and future range of Stipa barbata species for the next three decades (year-2050) was predicted under two climate warning models (scenario RCP4.5 and RCP8.5) using the logistic regression model. Output maps, with probability of occurrence between zero and one, to four categories unsuitable habitat (0-0.25), almost suitable habitat (0.25-0.5), habitat with high suitability (0.5-0.75) and habitat with very high suitability (0.75-1), were grouped. Finally, based on the coefficients of the variables in regression relationships, effective variables for the current and future range of S. barbata species were introduced. Based on the results; only temperature-related indices (BIO7 and BIO10) were found to be effective on the distribution of S. barbata species, present and future. The values of the indices increase with increasing climatic conditions. As a result, the range of S. barbata species decreases in response to climate change. This indicates during the next three decades, the presence of S. barbata species will decrease in the habitats of the region and there is a risk of its removal from the ecosystems of the region. In total, climate change and consequently increase in temperature characteristics causing the vertical spresd of S. barbata species, and it will move towards higher latitudes along the altitude gradient of the region.

Nonscientific land use changes can have negative effects on desired physical and chemical properties of soil. In this regard, the present study aimed to investigate the effect of different land uses (factories, rangeland, agricultural lands including saffron and wheat cultivation) on soil physical properties including soil texture (percentage of sand, clay and silt) and soil chemical properties such as (pH, EC, %OM, Ca, Mg, Cl, So4 and N) in Sarayan region in South Khorasan province. The research was conducted in a completely randomized design with three replications and six treatments. Treatments include different landuses, such as rangeland, wheat and barley use, saffron use and industrial landuse (Asphalt plant) at three distances of 50, 250 meters and 1000 meters. The results showed that the effect of different land uses on soil chemical properties such as pH, EC, Cl, So4, N, Mg and Ca is significant. Also, the effect of different landuses on soil physical properties such as the percentage of silt and sand, was significant. The results of soil chemical analysis showed that the factory located at a distance of 250 meters caused a significant increase in pH, EC, Ca, Mg, and Cl of the soil. Also, the results related to rangeland and agricultural use showed that saffron plant had the highest levels of pH, EC, Cl and So4 respectively (8.1, 2.6, 30 and 19.93) compared to rangeland and wheat. The effect of asphalt factory on chemical properties of soil to 250 meters had a significant effect on the growth of saffron plant, while the effect of distance on physical properties of soil to 50 meters was variable. The results obtained from this study showed that the use of unprincipled land use change reduces the quality indicators and the ability to use of soil and plants.

Desertification due to urban or technological development is due to human intervention and land use change, which is a serious problem. In addition to accelerating land degradation, population growth is leading to misuse of land. In the present study, using Landsat4-5 satellite imagery of 1986 TM sensor and Landsat 8 satellite imagery of OLI TIRS sensor of 2017, the trend of land use changes in Tabas city was investigated. The study area was divided into 6 units and using the Iranian Model of Desertification Potential Assessment (IMDPA), standard technogenic criteria and indicators were studied, and finally the numerical value of standard indicators of urban and industrial development (ratio of man-made to agricultural and garden lands, ratio of man-made lands to garden) And forest or green space, per capita green space index, percentage of road construction areas and road density, ratio of potential population to actual population) were calculated for the whole region in both time periods. Studies have shown that during the studied years, the level of man-made complicaions has increased by 5.68 percent, while arable lands have also increased by about 5.9 percent. The results showed that in the study area, the ratio of man-made land ratio, to garden and forest or green space and green space index with numerical values of 0.92 and 9.14, respectively, had the greatest impact in 1986 and man-made land ratio. To agricultural and horticultural construction and road density index with a numerical value of 0.79 and 1.95, respectively, in 2017 have the least impact on the technogenic desertification of the region. Based on the five indicators studied, the quantitative value of desertification intensity for the whole region in 1986 was 1.89, which is in the middle class of desertification, and in 2017, 7.13, which is in the very severe class of desertification.

Groundwater is the main source of fresh water in Nekarud region of Mazandaran Province. Population growth and the development of agriculture and industries has had a negative impact on the quantitative and qualitative characteristics of underground water in Nekarudd plain. Management and of these resources is necessary and unavoidable. Therefore in order to prevent environmental damages resulting from pollution and extraction of underground water resources in this region, principled planning should be done in the region. In this research, using three models DRASTIC, SINTACS and SI, the vulnerability of Nekarud plain aquifer was evaluated. For this purpose, first, the necessary parameters for the mentioned models including groundwater depth, nutrition, unsaturated zone, soil type, aquifer environment, topography, hydraulic conductivity, and land use were assessed and scored to prepare the overlay map. The nitrate and pH data of 2013 and 2014 were also used to validate the outputs of the models. The results showed that the DRASTIC model has the highest correlation value with nitrate, which is the main cause of groundwater pollution, and the north and northwest regions of the basin has the highest vulnerability value with 52.97%. The Mann-Kendall test to determine the trend of elements also showed that there is no trend of nitrate elements. But the value of ZS index for pH in 2013 was equal to 8.638 and it has an increasing trend. This means that this index had an increasing and significant trend at the level of 0.95 in 2014. The general result showed that DRASTIC is a suitable model for evaluating the vulnerability of the plain and planners and decision makers can use it as a suitable and cost-effective solution to prevent the increase of pollution.

Fires in Iran's western forests (semi-arid oak forests) are one of the main dangers in this region, which causes irreparable damage to ecosystems and the environment every year. Therefore, determining and predicting high-risk areas of fire helps to minimize the occurrence of fire and its damage by using fire risk models. The forests of Dalhu County (Kermanshah province), which are considered in the category of semi-arid oak forests, face this crisis every year and many forests prey to fire. In this research, identification and classification of high-risk areas of fire and preparation of map of high-risk areas of forest fires using Geographic Information System (GIS) and Analytical Hierarchy Process (AHP) in the forests of Dalahu County have been done. In order prepare a map of the high-risk areas of fire in the research area, influential factors such as forest cover density, Normalized Difference Vegetation Index (NDVI) evaporation (mm), slope and direction (degrees) and elevation above sea level.meter were used. The final map was grouped into five different categories of very low, low, medium, high and very high. Finally, the results showed that Dalahou's forest fires are include areas with very low risk 14.17%, low risk 32.48%, medium risk 33.43%, high risk 17.19% and very high risk 2.7%. The results of this study can be used for sustainable development policy at the levels of natural resources and environment.