Environmental Sciences
Year:2009 | Volume:6 | Issue:2|Papers Count:16

Plant symbiosis with microorganisms and other living organisms cause plant species stability and plant community protection. Mycorrhizae are one of the most useful symbiosis which both host plant and its fungi get benefit. Diversity of mycorrhizal fungi and the complicated relationship between plant and fungi community has been researched widely. In this research roots and rhizosphers of 10 families from eleven different habitats at Kerman were collected.14 dominant plant species has been chosen and examined for their dominance and growth form as well as root colonization percentage. The highest percentage of colonization was observed in the root of Juniperus excelsa (84.27) while Euphorbia gedrosiaca showed the lowest colonization percentage (37.22). Mean of spore numbers per gr soil were varied between 0 to 15.06 where rhizosphere of Aceraceae and Chenopodiaceae had the highest and the lowest spore numbers respectively. There was a significant positive correlation between the percentage of infection with both spore numbers and soil pH in the study area. Three genus of mycorrhiza fungi including Glomus, Acaulospora and Entrophospora were found in the soils.

Mnemiopsis leidyi which belongs to the Phyhnn Ctenophora has caused many ecological problems after entering the Caspian Sea. It seems that the high decrease in Kilka, Sturgeon fishes and Phoca population is related to the distribution of this Ctenophore in most regions of the Caspian Sea. So it seems necessary to know about all biological and ecological features of M leidyi. In this study the acute toxicities of the Water Accommodated Fraction (WAF) of the crude oil to Mnemiopsis leidyi and Acartia lonsa were determined and· their LC50 for 96h were compared. The experiment trials in 3 replicates was carried out in static system using similar bottles containing 1 liter filtered seawater and 10 individuals. The Pharmacologic Calculation System program was used to determine LC50. According to the results the LC50 was 3.311 and 0.148 ml.lit-1 respectively for M leidyi and A. tansa. It can be concluded that the invasive comb jelly (M leidyi) is significantly more resistant to WAF of the crude oil than Acartia lonsa. This study indicates that high resistance of Mnemiopsis leidyi to the marine pollutants in comparison with other marine zooplankton may facilitate the distribution of this animal in the Caspian Sea.

Fish diversity of Haraz River Was Studied from November 1999 To August 2000. This river is situated in The Southern Caspian basin of Iranian Mazandaran Province. Five Stations Were Selected along The River.522 specimens were Collected and studied, that belonged to 20 species and 9 families: Petromyzontidae, Cyprinidae, Cobitidae, Salmonidae, Gobiidae, Mugilidae, Balitoridae, Poeciliidae and Gasterosteidae.Cyprinids comprised 67.2 percent of the species.Seventy percent of species were resident and 30 percent anadromous. Rain bow trout (Oncorhynchus mykiss), Gold fish (Carassius auratus), (Liza saliens) and Stickle back (Gasterosteus aculeatus) and Gambusia (Gambusia holbrooki) were introduced species.Shannon- Wiener's coefficient of diversity (H’), Food selectivity and Horn’s coefficient of niche overlap were estimated.

The Eurasian otter (Lutra lutra) is a semi-aquatic mammal from Mustelidae family. It is recognized as one of the top predators in freshwater systems, and thus has the potential to play an important role in the functioning of these systems. There are only 2 otter species in Iran. Information about this species in Iran is absent. River ecosystems are one of the important habitats for otters. Jajrood River with 140 km length in the east of Tehran is one of these habitats that were selected for this study. To study otter distribution standard method was used. This method is a systematic sample survey for field signs of otters.16 survey sites at about 5 km intervals were selected and Otter signs, habitat parameters such as vegetation cover, river width and fish of river were recorded for each 600m stretch by walking the entire it (both banks) of all rivers, wading in the river wherever possible. A total of 599 signs (spraints, tracks, holst, rolling places and passes) were identified over the whole study period, the most common being spraints. Otter spraints were found in 6 of the sites of river Surveyed and in the study area, three core areas could be identified.

This is a one years field study to evaluate the recreational requirements of the Sysangan forest park in northern part of IRAN, adjacent to the Caspian Sea In this study, CLAWSOON (1959) method of site evaluation has been adopted. About 2500 questionnaires, with 21 questions in each, have been distributed among the visitors of park, during weekends &holidays, in a period of one years (June 2005-july 2oo6). The data so collected shows that, families and men are the major visitors of the ranging in age from 20 to 40 years old. It also shows that most of these visitors are from middle class having some sort of higher educations, working in government or private sectors. They visit the park in groups, preferring the forest and sea sides.Unadequate facilities of the park and protection of it in its natural status were among the visitors requests. Most of them believed that levying an entrance fee will promote the safety & facilities of the Sysangn park.

Landscape ecological metrics are quantitative tools that are used to evaluate the patterns of landscape. In this article we considered some landscape ecological metrics such as SDI (Shannon Diversity Index) or TE (Total Edge) to consider configuration and composition of the landscape patches.Then, a degradation model (DM) was conducted to compute the degradation hierarchy between working units. The DM was introduced as "LD" = SkI/V, where "LD" was degradation coefficient of landscape compartment, "k" (intensity) and "f' metrics of landscape, and "Y" was vulnerability of the natural habitat (here number of patches in each working unit).Thirteen sub watersheds in Sefidrod Watershed were considered and thus, degradation model was deployed to assess the status of each working unit. On the other hand, if there are deep red pixels in an infrared image, there are more areas of older ecosystems. Therefore, to reveal relationship between a metric and the status of the ecosystems in each working unit, the pixel number of deep-redness of infrared images was plotted against each metrics.Therefore, it was cleared that SDI has the highest correlation (R2=0.85) with the color intensity of infrared images.

In order to estimate different parameters such as heavy metals that existing in soil, changing point information to area are binge used. In this case, different method is existed. In this study, we used the Ordinary Kriging method for estimating amount of cadmium in soil the Esfahan province. Then map for estimating spatial distribution of the total cadmium with use of GIS ability, it was classified for recognition of the polluted regions with the cadmium. Variance analysis test shown that land use is significant effect on total cadmium existed in soil as, in urban and industry uses, mean of these heavy metals were much than their mean in the other uses.This explains that human activities are the most important factor for increase amount of heavy metals exists in soil Examination results of total cadmium description statistics and compare those with suggested value by the other countries shown that soil of this region is contains pollution for purpose of cadmium quantity. With use of ETM+ sensor and spectral unmixing techniques, vegetation covering of region was extracted and up to date. Amount of pollution expansion distinguished in different regions of vegetation covering with fitness to map of pollution soil and vegetation covering.

Zakherd watershed "with area of 82.23 km2" is located in the North West of Shiraz and East of Kazeroon in Fars Province. The evaluation of ecological land capability is considered as a core of environmental studies, as well as, preventive, and remedical measures for environmental crisis. So before the implementation of development, it is necessary to know about the ecological potential of land for different uses. In the Zakherd watershed evaluation is carried out by Mc.Harg method, 2001 makhdoum rural development ecological model and system of GIS. By this research, at first regional environmental resources was identified. Digital data with accompany of attribute data is entered into the Arcview system to make data base.Therefore, by overlaying information layers in the mentioned system the ecological unit map of area with the table of characteristic unit, and then the evaluation of capability was done. The result of survey shows that to the point of whole ecological parameters, the total region is not appropriates for rural development but by omitting of elevation parameter that its the last choice in the Makhdoum ecological model. 8.49% of land for rural development has a suitable (grade 2) and 91.51% of the other has not a suitable potential for rural use. For the complement of ecological evaluation, valuating needs, socio- economic indicator and facilities was done in the area so the three nappe of Zakherd, Elyasabad and Hematabab was put to make clear the hairchy of rural development by the result of search its made clear that Hematabad nappe has better choice.

This research is an attempt to develop a new method for studying the Urban Environmental Carrying Capacity with the aim of considering the process of monitoring and controlling of ecosystem health in the urban planning and management strategies. A new method was developed to address the waste production's spatial indicators to determine Degree of Carrying Capacity (DCC) in metropolitan Areas. The method was then examined in Tehran zones (Districts) for the year (2003). The results show that in 35 Districts (30%), The final Degree of Carrying Capacity of waste production's indicators is Critical (DCC=5), in 23 Districts (20%) is very high to Critical (DCC=4-5), in 48 Districts (42%) it is from medium to high (DCC=2-4) and in 9 Districts (8%) it is from low to medium (DCC=1-2) .None of the Districts has optimal Degree of Carrying Capacity.

One of the main differences between landscape ecology and other branches of ecology is the application of spatial concepts in ecological planning, Compared to the classical planning approach based on economic land suitability, the principles of landscape ecology are helpful in conserving the ecological processes of landscapes and simultaneously their steady changes, The aim of this study is to propose the application of the principles of landscape ecology m improving the quality of urban rivers, which could help in defining sustainable landscape development The Khoshk River, located in an arid and semi-arid climate, crosses the city of Shiraz. This river, as the case of this study, has been under pressure due to simplification of its complex natural pattern resulting from the growth of the city. The Impact of unplanned development of housing, agriculture and mdustries have threatened Khoshk River's natural environment The research method is based on assessment of human and biophysical units. Zoning in different, scales and determining the appropriate indicators based on the theoretical framework of the study and site characteristics help assess the ecological potentials and limitations. The results facilitate policy making and defining strategies for improving the Khoshk River ecological system. The method for analyzing the quality of urban rivers may be generalized in similar situations.

The healthy landfill of urban waste, such as every other engineering project, needs basic information and careful planning. Choosing different factors leads to diversity in data layers, consequently the attempts to find adequate solutions and make correct decisions directs the decision makers to apply systems which not only have high accuracy but also are fast and easy to be used in operations. Today "Geographical information Systems" (GIS) have the potentiality to be applied in environmental planning and engineering projects. fu present study, in order to select sites for dispose of urban waste of Tabriz, in addition to SPOT images, the following data layers and maps have been utilized; the steep map of the area, the maps of land use, land slide, road network, soil, hydrographic, underground water, dominant wind aspect, and the layers related to the distance from city center, airports and other important suburban areas. The results of present research represents that the conditions in Boolean method has less certainty and regarding to definite limitations in this method, the sites selected according to Fuzzy have fewer parameters, however in studying the two Fuzzy methods applied in this study (OWA and WLC). it revealed that although Weighted Linear Combination (WLC) is simple, it has some deficiencies; one of them is "overestimating", meanwhile Ordered Weight Analysis (OWA), by ordered weights, offers this chance to the decision maker to insert more important subjects which have greater role in site selection.Regarding to this ability the result of site selection by OWA has better resolution.

The present study has been done to find a suitable way to produce Wood-Plastic Composites (WPC) from Polyethylene terephthalate (PET) in accordance with the specifications mentioned in the National Standard of Iran. The experimental samples were prepared with 45 x 45 cm area; in 5, 10, and 16 mm thickness; 0.8 gr/cm2 density; altering weight proportions between % 20 to 49 of residual PET based on the total weight of the samples; using hot press method and these factored were as follows:Modulus of rupture (MOR);Internal Bond (IB) in vertical direction to the surface of samples;Swelling;Water adsorption after 2 and 24 hours submersion in water.The outcome of the present study proves that there is a good possibility to produce Wood-Plastic Composites with different thicknesses from PET residuals in 200 degrees centigrade under 3 min hot press; we achieved producing layered boards of 5 mm thickness, having %20 residual PET, %10 Polyethylene, and %70 saw-dust, in compliance with the above mentioned standard.

The Change in Population Demographics Causes Environmental concerns. People Participation in decisions regarding the placement of landuse is of major importance to relate people with their environment. With this approach environmental sustainability is achieved. Urban lands not only have structural dimensions but also have economic, social, environmental and cultural aspects.Therefore, it’s necessary to study all of aspects and find a holistic approach. The aim of this paper is to study new approach of placement of land use in the environment.