Environmental Sciences
Year:2009 | Volume:7 | Issue:1|Papers Count:20

Population increase and the illogical use of the natural resources of special forest cover have led to natural hazards. The study area is located in the northern Alborz in Chalos, Noshar, Noor and Amol cities and in Mazandaran Provice. In this study, we used the digital numbers from the landsat satellite TM and ETM+ data for two different dates (summer of 1988 and 2000). First of all, remote sensing images and the processing techniques were used in this study. Then, the images were analyzed using the NDVI index and Tasseled Cap transformations and, finally, the change detection process was studied. This research was analyzed using the trend of total land cover changes, thematic changes in each one and the forest cover area. The findings revealed that the forest cover area that, at the two different dates, it comprised 2719 Km2 (total 5121 Km2) and the greatest changes in area had taken place between the two period in the semi-crowded forest region. Local changes occurred in about 32 percent of the distribution of forest area. Investigations also mentioned show that there are vast changes in the spatial distribution of quantity accumulation, estimated on average at about 3.2 percent.

During this study, concentrations of Cd and Cr were determined in the muscle and skin of Liza aurata from Bandar Anazali. Forty-eight specimens (male:female ration of 24:24) were seined in October 2006 and their tissues were separated according to UNEP’s method (1984). Oven-dried and homogenized samples were digested as per the standard method of AOAC (1995). Concentrations were determined using a flame atomic absorption spectrophotometer. The data analysis by a paired t-test showed significant differences between concentrations of Cd and Cr in the muscle and skin of Liza aurata, with skin showing elevated metal levels. Linear regression analysis showed a significant negative relationship between fish size and the Cr levels in muscle. There was a significant increase in Cr and Cd levels in skin with increased size of the fish. Independent t-test analysis showed that average metal levels in the tissues of female fish were higher than in male fish. This study concludes that the concentrations of Cd and Cr in tissues of Liza aurata are low and do not constitute a risk to human health.

Reducing the impact of harvesting on residual stand and regeneration is very important, considering the use of close-to-nature forestry for Hyreanian forest management and the low cutting volume distribution of this method. To obtain these objectives, this research was carried out in 220 compartments of Namkhaneh district, in Kheyrud Forest. In order to determine the damage to residual stand and regeneration, 50*50 m systematic sampling with a random start was used. Data of the damage to regeneration and trees were collected in circular plots with 0.01 ha and 0.05 ha after chainsaw tree felling, respectively. Results of the data analysis showed that about 7% of remaining trees and 23% of residual regeneration were damaged in the study areas. Also, these researches showed that the amount of damage to the seedlings was smaller than to the small sampling and thicket. Training of tree cutting crews is the most important factor for decreasing residual stand damage after harvesting. The residual stand damage from a cutting operation was studied in an uneven-aged mixed forest to examine the main factors (i.e. tree species, location, size, and type) affecting stand damages. Directional tree felling in a forest stand and using some helping instrument could be useful for decreasing the residual stand damage.

This study aims to analyze the reasons for and obstacles to adopting IPM Technologies among rice farmers in Mazadaran and Guilan provinces. 170 farmers that attended a FFS (Farm Field School) groups but did not adopt the IPM Technologies were randomly selected. Data were collected by questionnaire and analyzed by SPSS software. To determine the main causes of non-adoption and underline these, factor analysis was used.Results revealed that the main causes of non-adoption of IPM Technologies were financial reasons, farmers’ own personal characteristics, risk and vague spheres, management issues, insufficient information and technological questions. These causes were explained with a 58.8% variation. Finally, based on the results obtained, promoting conflict management by focusing on a problem solving approach and institutional development to eliminate obstacles and to promote adoption was suggested.

In an early definition of environmental quality, satisfaction is one of the key criteria by which the extent of environmental quality may be determined- an environment of high quality conveys a sense of well-being and satisfaction to its population through characteristics that may be physical, social, or symbolic. Assessment of the factors leading to satisfaction and dissatisfaction from the residents’ point of view can be used as criterion for the planning and design of urban development projects. This research was undertaken in he Navab neighborhood of Tehran. Data collection was conducted through a field study using a questionnaire filled in by a sample of 270 residents. Data analysis was also conducted using SPSS software. Analysis of the results shows the residents’ satisfaction with their houses to be at a mid-level; in the theoretical mode it was estimated to be 3. Factors including the satisfaction with residential units felt by their residents show that full satisfaction was only expressed on the level of security of the residential complex. The factor of “relationships among neighbors” was estimated at a mid-level. Other factors such as the facilities of the residential complex, landscape and view, and the physical significance of the complex were rated with dissatisfaction. The results of factor analysis support this experimental model by high level (89%). This was concluded from a literature review of similar subjects. On a factor analysis of personal and family variables and their impact on satisfaction levels expressed by the residents, none of these variables had any effect.

In recent years, the Caspian Sea has become one of the most important strategic areas of the world. However, in spite of its economic potential, the huge exploitation of its reserves along with in increase of the presence of different industrial plants in the sea have caused many problems for its ecology and the environment. The Convention of Tehran to protect the Caspian Sea, as a symbol of regional cooperation, has been adopted by the coastal countries in order to limit the increasing trend of destruction of the sea. Littoral states of the Caspian Sea have ratified this Convention, emphasizing the importance of regional cooperation in saving the Caspian Sea and the necessity of cooperation with related international organizations. The Convention can provide a legal framework to restrict pollution to the Caspian Sea. The fact is that the trend of destruction is faster than the level of environmental cooperation. In this article, by considering the environmental threats for the Caspian Sea, the authors will survey the history and the process of formation of the Tehran Convention. The goal of this article is to identify the capacity of this Convention to decrease the environmental threats to the Caspian Sea.

In this study, the effects of education on increasing individual willingness for the conservation of the Caspian Sea have been investigated using a random sampling method and collecting 400 questionnaires in the seaboard provinces in Iran. Five different informative brochures about the ecosystem of the Caspian Sea and its crucial role in human life were handed to 200 people as intervention group. The control group also included 200 people. Data were analyzed using the contingent valuation method (CVM) and Logit function. Results show a significant difference between the two groups in their willingness to pay (WTP) for conservation of the Caspian Sea environment. Estimation of the Logit model showed that educational intervention has a significant effect on individual WTP for the conservation of this ecosystem. Each additional brochure with information increases the probability of a willingness to pay by 0.104 units, respectively. Also, other variable effects and investigated and, among them, education and income were more effective in increasing individual willingness. In the control group, the income variable was more effective. Monthly individual willingness to pay for conservation of the environment in the control and intervention group was estimated at 5370.8 and 8662.3 Rials, respectively. Annual WTP for each household was estimated at about 205594.2 and 3154479.4 Rials in the groups mentioned. According to the results, an increase in information about the importance of the Caspian Sea, lead to a higher WTP for conservation of this ecosystem.

In order survey the resistance of wild populations to clodinafop propargyl herbicide, an experimental study was conducted at the Department of Weed Sciences, Plant Pest and Disease Research Institute greenhouse in 2008. Treatments included 12 wild oat populations suspected of being resistant to clodinafop propargyl and a susceptible biotype collected from Fars Province. A dose-response study was conducted for 13 wild oat populations. In this study, wild oat population were sprayed during the 2-4 leaves stage using eight doses of clodinafop propargyl including 0 to 16 times the recommended dose (64 g ai ha-1). Biomass and surviving plant measurements were performed four weeks after herbicide application. Results of this study indicated that all suspected population were resistant to clodinafop propargyl herbicide. The comparison of resistance index on the basis of biomass and surviving plants showed that the W/F-M2/85 population from Marvdasht had the highest level of resistance. This population could preserve over 50% more of both biomass and surviving plant relative to the control at 16 times (1024 g ai ha-1) the recommended dose.

Today, availability and best use of energy resources is one of important laws of development in countries. The vast reserves and cheapness of fossil fuels in Iran has lead to improper usage of these resources and a failure to use other resources seriously. Unlimited usage of this resource and its smuggling to foreign countries has resulted from this energy policy. An increase in the usage of this fuel created the conditions in which the government, in July 2003, rationed petrol with the aim of saving it. Energy and fuel resources have a variety of usages: in the transportation industry, providing energy for factories and domestic uses such as heating, cooling, cooking and lighting. Because of its natural geographical situation (topology) and vastness, our country enjoys a variety of energy resources in addition to fossil fuels (Sabouhi, 1998) such as wind, tide, geothermal, the sun and its rays (solar) which are renewable energies that can be used with less preparation (Taqzi, 2003). One of these resources which can be found in most villages in our country is biomass, which is the basic source of methane gas and its use for household fuel and producing electricity. Application of alternative energies, which are abundant in Iran, while providing necessary energy in villages can also help to reduce the use of fossil energy resources in the country. This article analyzes the production of energy from biomass resources, a simple design structure and the building of the tanks, and the influences of its usage on the environment, fabric and rural housing. The first part of this paper introduces biogas and experiments of other countries in this field. The second part analyze the equipment and basic tools which are required for producing biogas, and also important aspects of designing and manufacturing a variety of tanks in villages. At the end, in addition to introducing design principles of the housing unit with a biogas tank, I will analyze the positive influences of ecology on the housing units.

This research is committed to providing methodological guidelines for the simulation of urban land use dynamics using. GIS, RS and CA models. Urban-CA modeling experiments have been conducted for a medium for a medium-sized city (Shahr-e-Kord) in Iran over a thirty-five year time span. Global transition probabilities obtained from the Markov chain model and Unique Conditions Map were derived from WoE. Local transition probabilities were estimated using infrastructural factors by two different probabilistic empirical methods: the WoE approach, based on Bayesian theory; and logistic regression. The final land use transition rules drove an Urban-CA mode, built upon basis of stochastic land use allocation algorithms. These Urban-CA models drive a CA model based on eight cell Moore neighborhoods. The simulation outputs were statistically validated according to a new compound method based on a Multiple Resolution Model (MRM). After achieving simulations for the 1999-2002 and 2002-2006 time periods along the whole time series, forecast simulations were carried out up to 2025 (1404) and for various urban planning scenarios. For all simulation periods, the best results were obtained from a combined Markov chain and logistic regression with 0.5 Gama to derive the transition rules. Different simulation outputs for the case study indicate their possible further applicability for generating simulation of growth trends both for Iranian cities and cities world-wide.

Residue management is one of the optimistic options for sustaining agroecosystems. In order to investigate NO3 and NH4 dynamism with the application of soybean and cotton residues incorporated with a silty-clay-loam soil (0-30 cm), an aerobic incubation experiment was carried out suing three residue treatments (including cotton residue, soybean residue and cotton residue+urea to eliminate immobilization). The residue amount was determined in order to provide 150 Kg ha-1 of Kjeldahl nitrogen after incorporation with soil (this was done using the nitrogen factor method). The samples were incubated for 175 days under a controlled environment at 25oC. The NO3 and NH4 concentration and bacteria, fungi and Actinomycete populations were measured 7, 14, 28, 67, 109 and 175 days after incubation began. The results confirmed microbial activity dynamism during time. Cotton residues revealed a non significant prevalence on soybean residue with respect to cumulative nitrate and ammonia, which were released during the incubation period. In all cases, the cotton+urea treatment was better than both other treatments. These results were not interpretable based on the C:N ratio and the results showed that the lignin content is probably more important than the C:N ratio (lignin percentage of cotton and soybean residues are equal to 0.7-1.6% and 14%, respectively). In this study, the relationship between nitrate and ammonia dynamism with microbial communities have been analyzed.

It has been controversial issue in recent decades that economic activities may put the environment in serious danger. Some believe that moving toward a healthier (more uncontaminated) and less polluted environment and also uproot poverty requires economic growth. In environmental economy, the relation between pollution and per capita income, which is the shape of a reverse U, is known as "Environmental Kuznets Curve", EKC. In this study the application of Kuznets Curve to OPEC countries has come under investigation. For the theory test, CO2 has been employed as a stock polluter. The investigation has been performed using the panel data of the time period between 1985 and 2006. The results of the stationary test have revealed that the variables are non-stationary. Therefore, in order to study the existence of co-integration between variables, a Pedroni test of co-integration has been performed. The results of this test confirmed that a long term relationship existed between the variables. Also, between random effect model and the fixed effect model, the latter was accepted according to the Hasman test and the Kuznets Curve was estimated. The results rejected the Environment Kuznets Curve theory for OPEC countries and, as a matter of fact, the quantity of the CO2 gas disseminated through the environment has constantly increased along with process of economic growth.

The expansion of urbanization and the development of cities along with increasing population and expansion of industrial activities and irregular consumption of fossil fuels have given rise to pollution. At the first stage, its consequences impact on citizens in terms of respiratory illness and increased intensity of heart and lung diseases and, at the second stage, it plays a role in increasing climate fluctuations and environmental impacts. In the current study, two types of data are used in investigating the relationship between parameters and elements. The first data under study are the climate parameters during statistical period of 51 years from 1952 to 2003, divided into three 17- year periods a clean period (1952-69), an intermediate period (1970-86) and a polluted period (1987-2003) - whose fluctuations and climate vicissitudes are compared. The second variable or data under study are the type and amount of pollutants in Tehran city during 1997 to 2003m taken as an annual average. Totally, after various calculations, the conclusion was that during the polluted period the climate of Tehran had more fluctuations than in the two previous periods and, during the polluted period, the fluctuations of the region were seen in temperature increases, increasing potential for flooding and change in climate towards a warmer and more humid state.

The effects of water deficit on the yield and essential oil percentage of yarrow (Achillea millefolium L.) were investigated at the Ablborz Research Center (Karaj, Iran). The treatments were irrigated based on total accumulated evaporation from a class A pan, namely at the rate of 30mm (mild stress), 60mm (medium stress), 90mm (severe stress), full irrigation (no stress) and no irrigation (dry farming). The treatments were analyzed in a completely randomized blocks design. Data from three years were analyzed using a combined analysis method. For each treatment, the soil moisture content was measured by the weighing method (daily) before and after applying irrigation treatments based on the above mentioned rate of evaporation. The amount of water required for each treatment was measured by a current meter. The combined analysis of data gathered from the experiments revealed that the effect of the rate of water deficit stress, years (through varying metrological conditions) and also the interaction between them had a significant impact on the biomass, flower yield harvest index and essential oil percentage of this species. The comparison of means showed that, in the first year, flower yield was 1169.70 kg/ha significantly different from the third year. The full irrigation treatment (no stress) produced the maximum flower yield of about 1360 kg/ha with no significant difference in comparison with the mild stress treatment. The effect of interaction between the years of experiment and the rate of induced stress level indicated that a full irrigation treatment in the second year produced the highest yield of 2551 kg/ha. The highest harvest index (ratio of flowers to biological yield) was observed under mild stress, particularly in the first year (22.01%). The highest essential oil percentage extracted from flowers was obtained under the severe stress treatment in the first year (0.58%), which is significantly different from other treatments. The experiment showed that full irrigation and severe stress reduced yield and essential oils. But mild and medium stresses increase flower and essential oil percentage.