نشریه محیط زیست طبیعی
سال هفتاد و پنجم شماره 4 (زمستان 1401)

In Iran, brown bears are in a wider range of conflicts with people than other carnivores. However, understanding the factors leading to conflict is a conservation priority, which helps prevent and reduce the damages. The aim of this research is to investigate the factors affecting brown bear conflicts as well as strategies used by local people to reduce the damage caused by this species in the Roshan Kooh no-hunting area, Fars Province. We used Daniel method for sampling by considering the size of households living in rural areas, and 200 questionnaires about the factors affecting brown bear attacks and the strategies used by local people for reducing damages were designed and local people were interviewed in 2019. For this purpose, social network analysis method was used. The results showed that from the perspective of the local communities, drought, brown bear stimulation and lack of fencing around orchards and beehives have the most centrality among the factors affecting brown bear conflicts with human. Among the solutions used by local people, the level of public trust before and after using educating children and inexperienced people, fencing around the orchards or beehives, and using herding dogs, is higher than other methods. The significant results of this research are the reduction of the centrality with the help from the Department of Environment (DoE) after use, which shows the low trust of local people after referring to the DoE. With the determination of the central role of education for children and inexperienced people, it is suggested that education to local communities is considered as a top of the management programs of the DoE.

Today, the use of raster data from climate databases such as WorldClim is one of the reliable data sources that have been used instead of the point data of weather stations. However, the use of these climate databases with low spatial resolution has generated limitations for many studies related to biological and ecological studies. This study aims to investigate the relationship between air temperature and land surface temperature and then reproduce the land surface temperature with the high spatial resolution for downscaling of annual average air temperature using two widely used products, namely,  annual average air temperature from the WorldClim database and annual average day and night temperature from MOD11A2 v061 MODIS sensor. In this study, firstly, the performance of machine learning models including random forest, artificial neural network, elastic network regression, and support vector machine for downscaling of MOD11A2 v061 product from 1 km to 250 meters was assessed. For this purpose, continuous and discrete predictor variables including height above sea level, latitude, vegetation cover, soil texture, slope direction, and land cover were used. Then, WorldClim's annual average air temperature was downscaled from 1 km to 250 meters using the land surface temperature with a 3rd-degree polynomial regression model.  Also, the weather data of seven synoptic stations were used to check the validity of the downscaled product. The results of the Taylor diagram represented that the random forest model has the best performance for the downscaled land surface temperatures with a root mean square error of 0.54 degrees Celsius. Also, the 3rd-degree polynomial regression model has a lower relative error rate in producing downscaled air temperature. The value of the root mean square error of the results for the uncorrected and corrected downscaled air temperature was 1.32 and 1.21 degrees Celsius, respectively, which did not show a significant difference at the 0.05 level according to the paired t-test. The findings of this research show that the downscaling of the mean annual air temperature of WorldClim has the required validity.

The Gavkhuni playa is located 130 km southeast of Isfahan. This playa consists of three mud, sand and salt flats. The mud flat mainly covers northern part of the playa (the Zayandehrud delta). A sediment core was drilled in order to study heavy metals pollution in the subsurface mud sediments of the Zayandehrud delta. Accordingly, 7 facies including black mass mud, brown mass mud, black mass sand mud, brown sand mud, light green mass mud, light green sand mud and brown gypsum bearing mud, and 5 sub-environments of branching canals, canal margin, lake and playa were identified. To determine role of the physicochemical factors in concentration changes and pollution of the heavy metals in the facies, granulometry of the sediments was carried out through wet sieving and hydrometric methods. Eh and pH, calcium carbonate and organic matter contents and heavy metals concentration in the sediments were measured asx well. Average concentrations of the heavy metals (in ppm) in order of their abundances are Mn (576.46), Zn (79.73), Cr (50.84), Cu (46.32), Ni (37.40), Pb (10.99), Co (09.09) and Cd (0.092). According to the correlation between the heavy metals and physicochemical parameters and also cluster analysis, the retention of Mn, Co, Ni and Cr has been affected by clay, Fe oxi-hydroxides and Eh whereas the contents of calcium carbonate and organic matter have been effective in the adsorption of Cd, Zn, Pb and Cu. The indices of sediment pollution to heavy metals including the Enrichment Index (EF), Geoaccumulation Index (Igeo) and Pollution Accumulation Index (PLI) indicate that despite changes in the sedimentation condition, sediments of the drilled core show no pollution. Based only on the Igeo index, the sediment samples show little pollution to Zn, Cu and Cd.

Population growth and urbanization lead to mass production of waste. When municipal solid waste is landfilled, complex biological, chemical, and physical reactions occur that lead to greenhouse gas emissions. Methane is an important greenhouse gas, and the concentration of methane in the atmosphere is about 200 times lower than the concentration of di Is carbon monoxide, however, methane accounts for about 20% of heating. Emission of methane gas into the atmosphere will cause destructive environmental phenomena that reduce the stratospheric ozone of the ozone layer and over time increase the Earth's temperature. First, using the IPCC model, the amount of methane production in the Landfill of Halghe-Darreh in the study period from the beginning of 2015 to the end of 2019 is calculated and equal to 274.98 thousand tons of waste per year and the emission rate of methane gas in the landfill using the IPCC model. In the above time period is equal to 0.75 (g / sec). Then, the distribution of methane gas over a period of five years was investigated using the AERMOD model. The results showed that the distribution of methane gas with the AERMOD model for the whole landfill in the studied period in the northwest and southeast direction Around Landfill). Also, the maximum and minimum methane gas concentrations in the five-year period were 719.87 and 97.19 mg / cubic meter. Therefore, using two models, IPCC and AERMOD, the production and distribution of methane gas were calculated and the filling map up to 50 km of landfill was drawn.

In order to promote the economic activities of a country, it needs a productive and healthy financial structure and financial development as the backbone of the country's economic development. The debate over the impact of natural resources and their impact on financial development has been an important area of ​​research over the past few decades. The present study examines the asymmetric relationship between financial development and natural resources by combining the variables of real GDP, capital, education, globalization and natural resources using annual data from 1979 to 2018.  In addition to the standard unit root test, this study uses a single root test with several structural failures. The Maki co-integration method is also used to determine the long-run relationship of up to 5 structural breaks. In addition, self-explanatory co-integration with wide nonlinear intervals is applied to determine the long-term asymmetric relationship between variables. Long-term results show the confirmation of the positive effect of natural resources with coefficients of 0.175 and 0.611 on financial development in long-term positive and negative shocks. In addition, education with a coefficient of 6.983 has a positive and significant effect on financial development in the long run, while GDP has a significant negative impact on financial development in the long run. Also, the existence of an asymmetric long-term and short-term relationship between natural resources and financial development has been confirmed. This shows that significant investment in the banking sector for Iran can affect the natural resources sector.

Vegetation consist of collections with spontaneous growing. MODIS vegetation index plays an essential role in several studies about EOS (Earth Observation System). The aim of this research is evaluation of vegetation trends in Central Plateau of Iran. This aim was done by remote sensing data and time series. Using the data are related to (MOD13A2) MODIS sensor and Terra satellite and they are 16 days with spatial resolution 1km during 2002 to 2018. For this purpose, we used from significance of Mann Kendall and linear correlation parameters such as maximum monthly vegetation maximum annually vegetation based on maximum monthly vegetation at 1% level were used. Analyses show the similarity between two significant methods, so considering of vegetation trend is possible with using both of them. Regarding arid and semiarid of the region, based on similar study, PVI1 vegetation trend is considered as a suitable vegetation in the area of study. Considering significant trend of this vegetation indicates that in Central Plateau of Iran, increasing of significant in vegetation in Qom, Semnan, South Khorasan, Esfahan and Yazd provinces are visible (Values ​​greater than +0.18 for monthly images and numbers greater than +0.606 for annual images). Also, decreasing significant of vegetation was observed in Khorasan-e Razavi, Qom, Esfahan and Yazd provinces (Values ​​less than -0.18 for monthly images and numbers smaller than -0.606 for annual images). Result of this study indicates sensitive and vulnerable regions in Central Plateau of Iran that can be effective in better management of vegetation in the future.

Rangelands are one of the most important renewable resources that play a vital role in the preservation and sustainability of the environment, water and soil resources, and livelihood security for rural communities. However, overgrazing has led to severe soil erosion on many rangelands in recent years. An important strategy for rangeland conservation, which has received less attention in previous research, is to change rancher behavior in a pro-environmental direction. Therefore, this study focused on determining the factors that influence ranchers' use of rangeland conservation behaviors (RCB) in western Iran. Therefore, this study was conducted with the general aim of the role of social capital on rangeland conservation behavior among ranchers. The study statistical population consisted of all ranchers in the Saral district of Kurdistan province (Western Iran) who were selected through a multistage stratified sampling procedure with appropriate allocation. The main research tool was a questionnaire whose validity was confirmed by a panel of experts and its reliability by Cronbach's alpha coefficient. The results of this study showed that the studied ranchers do not perform rangeland conservation behaviors well and in addition, the results of regression analysis showed that the dimensions of social capital (social norm, social awareness, collective action, social cohesion, social trust) are able Explains 65.2% of rangeland conservation behavior. In this regard, policymakers in this field are suggested to prevent its excessive destruction by forming cooperatives and holding training courses in the field of rangeland protection.

This study was conducted to investigate the habitat preference of Capoeta damascina in the Sirvan River using the kernel smoothing method. For this purpose, in November 2021, eight stations each with 3 replications were sampled using an electrofishing device. A total of 135 specimens were sampled, identified and released. Ten environmental factors, including pH, temperature, total dissolved solids, electrical conductivity, altitude, depth, width, velocity, slope and dissolved oxygen were measured. The results showed that the habitat preference of C. damascina in the Sirvan River based on the studied factors are habitats with pH of approximately 6, temperature 9°C, total dissolved solids 200, electrical conductivity 300 μS/cm, altitude 1130m, depth 50 cm, width 9 m, velocity 0.8 m/s, slope 2% and oxygen 9 mg/liter. The SI values of altitude (0.92) and oxygen (0.79) had the highest values. The results showed, Sirvan River with HSI value of 0.69 is a suitable habitat for C. damascina.

This research aimed to investigate co-digestion and the effects of alkaline pretreatment conditions on substrate degradability and methane production from municipal solid waste (MSW) and sewage sludge (SS) in a pilot and experimental approach in non-continuous reactors with a retention time of 30 days. For this purpose, co-digestion of the organic fraction of MSW and SS with 5 mixing ratios of raw materials was evaluated to evaluate the biogas and methane production from it in with mesophilic temperature conditions (37 °C). Therefore, the results showed that the increase of SS (up to 40% by weight of raw materials) in feed led to increased methane yield, while longer retention times were obtained by increasing the percentage of MSW. So, the ratio of MSW (60%) and SS (40%) (60:40) was determined as the preferred ratio for optimal biogas production. Based on the preferred ratio, the effect of different concentrations of alkaline pretreatment (2, 6 and 10% NaOH) for different time periods (1.5, 3 and 6 hours) on the biodegradability of MSW, biogas and methane production was evaluated. The results showed that the best improvement was with the treatment at a concentration of 6%NaOH for 3 hours, which led to a 30% improvement in methane production. Other treatments were also effective, in which 6%NaOH treatment for 1.5 hours resulted in a 17% improvement in methane yield compared to the control sample. Therefore, alkaline pretreatment significantly improves the decomposition of solid organic waste and thus increases methane production.

While a great number of researches have focused on identifying the factors affecting carbon emissions, the role of economic policy uncertainty (EPU) on environmental quality has been less studied in the energy-environment literature. In this regard, the purpose of this study is to investigate how economic policy uncertainty affects CO2 emission in the group of developing countries with the highest levels of pollution. In addition, the moderating effect of economic policy uncertainty on CO2 emissions from renewable and non-renewable energy channels has been studied.  The results show that there is bidirectional causality between economic policy uncertainty and CO2 emissions. Then, a panel data model by the Generalized Method of Moments (GMM) is estimated to address the endogeneity problem. We find that increase in economic policy uncertainty has led to higher CO2 emissions. Furthermore, our findings underscore that 1 percent increase in the consumption of renewable energy has led to decrease CO2 emissions by 0.026 percent. In contrast, the consumption of nonrenewable energy has led to increase in CO2 emissions by 0.98 percent. Also, the results show that increase in economic policy uncertainty has led to a reduction in non-renewable energy consumption and thus a reduction in CO2 emissions during the period 2004 to 2020.

During the last few decades, Land management decisions and consequently the land use\cover change in the Zagros biomes affected the ecosystem services value and their spatial distribution. The purpose of this study was to determine how land decisions affect spatial indicators of balance and equivalency of ecosystem services values during a period of 30 years (1990-2020) in Kohgiluyeh-Boboyrahmad province. Initially, LULC was extracted from Landsat and Sentinel satellite images using an object-oriented processing method. In addition, the benefits transfer method was applied to estimate ecosystem services' economic value, and the sensitivity indicator analysis process was applied to measure their uncertainty. Ultimately, by developing a gravity index and performing spatial statistical analyses in a 1km fishnet, we monitored the spatial balance and equivalence of ecosystem service value. The results show that the change in the ecosystem services value was mainly due to the intensity of unbridled man-made land (9.8%) and agriculture (6.3%) during the study period. The findings also show that the total value of ecosystem services has decreased by 3% over 30-years (152.6 Thousand Billion Tomans in 1990 to 148.5 Thousand Billion Tomans in 2020). As the sensitivity index is low, the modeling is reliable, accurate, and flexible with low uncertainty. Spatial analysis of hot spots shows a 2% decrease in areas with high potential for ecosystem services. On the other hand, the changes in the gravity centers the ecosystem service values in the period under study are substantial, as the center of gravity has moved 400 meters to the southwest over 30 years. Because of severe human intervention, the total ecosystem services value had been nonequalvalnce, resulting in 1.4 Thousand Billion Tomans in losses. Estimates in the research show restoration of oak forests in the southern and eastern regions of the province and increasing the value of services by 87 billion tomans can provide the necessary ground for the return of balance to the land.

Soil contamination with heavy metals is a serious issue in all the world, and these heavy metals are released from both natural and human resources, especially agricultural activities in the environment. Therefore, in this study, the amount of heavy metals and the indicators of ecological risk potential and integrated pollution in soil samples before rice planting and after rice harvesting in Mazandaran province have been investigated. A mixture of nitric acid, hydrofluoric acid and perchloric acid was used for chemical digestion of soil samples and ICP-MS was used to measure the amount of heavy metals in soil samples. The results of comparing the levels of chromium, zinc, nickel and lead in the soil before rice planting and after rice harvesting with the national and international soil standard show that the levels of these metals in most stations are higher than Domestic and international standard limits were measured. Based on the results, the amount of ecological risk potential index in soil samples showed that in all studied stations ana sampling stages, the amount of this index was calculated in the range of low ecological risk (below 150). Also, the results of PI pollution index and integrated pollution index (IPI) for each studied station in soil samples before rice planting and after rice harvesting show the PI index for arsenic, chromium, cadmium, copper, nickel, zinc and mercury. In all stations in soil samples before rice planting and after rice harvesting in the range of low contamination was calculated, only the amount of this index for lead in all stations and sampling stages, in the range of moderate contamination was obtained. Also, the results of IPI for all studied stations in all stations and sampling stages, show that the level of this index was determined in the low pollution range. In general, the presence of heavy metals in the soil environment, followed by the accumulation of heavy metals in food, has detrimental and irreversible effects on human societies and food security, so more precautions are needed to reduce such effects.

The Eurasian otter (Lutra lutra) as one of the mammals of the inland waters of Iran is at the top of the food pyramid and encounter to endanger of extinction. The diet studies are critical to understanding the ecology of wildlife and preserving their populations. The objectives of this study were the presence and diet of otter in estuary region of Acharod, Khoshkrod and Polrood rivers, in the east of Guilan province, and also the study of the level of dependency of this species on fish species of the Caspian Sea. The length of the last five kilometers of each river, as three sections with an approximate length of 1700 meters, was examined in terms of distance or proximity to the sea. The results showed that of the five km length studied of the rivers, the Eurasian Otter was present up to 4/3 km of the estuary. In total, 511 presence indices with specific seasonal changes were observed in each of the river sections. The highest index was observed in the autumn season and the lowest in the summer season. Based on the analysis and investigation of spraints, 955 prey items including fishes, crustaceans, snakes, frogs, birds and insects were observed. The highest feeding index (FI) in three studied rivers was for fish and the lowest FI was for insects. Also, the seasonal changes in food items between sections were observed. So that in the two seasons of autumn and winter in all three sections of the rivers, the highest FI was for fish. In the spring and autumn, the feeding index of the fed fish was mainly related to river fish and common river-sea fish. In summer and winter, the percentage of sea fish was higher than in spring and autumn. The feeding index of non-fish items has also increased in the summer compared to other seasons.