Environmental Sciences
Year:2007 | Volume:4 | Issue:3|Papers Count:11

The study was conducted to explore fish species composition of the international wetlands of Golestan province, which represent a series of the small and rather isolated freshwater lakes during September 2000 to August 2002. The results revealed that non-indigenous fish species are dominant in the wetlands. Of 10 sampled species, four including Sharp Belly Hemiculter leucisculus, Silevr Crucian Carp Carassius auratus, Top mouth Gudgeon Pseudorasbora parva, Mosquito fish Gambusia holbrooki, were non-indigenous. Alma- Gol and Ala-Gol contained 89.80% and 79.57% (of total frequency of fishes) of none-indigenous species respectively, indicating decreasing of native fish fauna. The most frequent noneindigenous species were H. leucisculus in Alma- Gol (58%), C. auratus in Ala-Gol (77.6%) and H.leucisculus in Adji-Gol (16.82%). As numerical abundance, two none-indigenous species H. leucisculus and C. auratus had the highest biomass in the Alma-Gol and Ala-Gol respectively. This situation highlights the importance of conservation and protection measures. Therefore, if greater emphasis is not placed on the conservation of native fishes with no direct economic values, these species could face continuous decline or might be completely lost.

The cultural heritage is accepted as forming an element in the environment and, as such, it is important to evaluate the effects of various activities, including tourism, on it. The purpose of this paper is to examine and identify the general trend of attitudes among residents of an historic city and World Heritage Site towards tourism development. A fundamental assumption underling this paper is that "environmental" impacts should be regarded not only as those affecting ecosystem function, for example, or even the aesthetic values of a land-or city- scape but also the social fabric of the locality. As such, this paper provides the first social impact research on such an historic city in Iran by measuring the host community's attitudes towards tourism development. The primary goal here is to establish a theoretical and empirical study for the city of Esfahan, enabling future comparative analyses of host attitudes. A sample was chosen from among local residents and regression analysis was applied in order to discover if there are any underlying dimensions concerning their attitudes towards tourism development, and whether socio-economic and demographic characteristics can be useful predictors of these attitudes.

Urban spaces form main dynamic spaces of cities and towns. Different disciplines have theorized urban spaces and have heavily shed some light on the process or nature of the urban spaces, but the concept of the urban spaces is highly unknown yet and the gap between urban theories and practices is not clear too. The aim of this article is to propose a conceptual pattern for surveying and analyzing the urban spaces to decrease the gap between theory and practice based on the real world. This article is consisted of two parts. In first part, it aims to propose a conceptual pattern which is named Sustainable Socio-Spatial Pattern to survey and analyse the urban spaces. In the second part, it has been applied in Greenwich Millennium Village, a major development in London city, U.K. So, this article has resulted a conceptual pattern in at least two approaches: Process and Substance which can apply in complex and multi-layered urban spaces.

Recent studies have shown that certain man-made compounds (including some pesticides) have the capability to induce developmental and reproductive abnormalities in humans and animals by interfering with endocrine system. Pesticides are currently being used a on large scale in many developed and developing countries (including Iran), so this study has been conducted to determine the percentage of endocrine disruptor agents in pesticides used in Fars Province. The results showed that more than 1,581,690 liters of pesticides from 86 different brands, have been used in Fars province during the Iranian year 1380 (2001/2) and 25.93% (34 types) of them had at least one carcinogenic agent. At least 30 pesticides (711,720 liters or 44.99%) had one endocrine disruptor agent and therefore can be classified as environmental hormones or endocrine disruptor chemicals. The percentage of pesticides found to be interfering with normal endocrine system activity were 7.82% (66,572 liters), 4.54% (39,975 liters), 22.02% (348,400 liters), 5.12% (81,000 liters) and 21.18% (34,500 liters) which were antiestrogenic, antiandorgenic, antityroidic, antigonadotropin and anitestroid hormones, respectively. The results showed that about 50% of pesticides currently being used in Fars Province should be prohibited.

Distributed hydrological models of sediment and runoff estimation for simulating the sedimentrunoff- precipitation processes in watershed surfaces require digital maps and some other information of the basin’s elevation. For example, the correct execution of erosion models which, according to the RULSE method, work in a distributed environment greatly depends on the quality of such information. The Digital Elevation Model (DEM), slop, flow direction and accumulative flow are considered as topographical derivations, a number of which can be extracted by standard Geographical Information Systems (GIS). According to the kind of interpolation method and DEM cell size, errors like digital holes and flat zones occur in the DEM. These errors usually cause some problems in the representation of the basin runoff and sediment delivery by hydrological and erosion models. In order to examine different methods of eliminating DEM errors, three algorithms are compared in this paper, namely: D8, DE and combination D8 and DE. The parameters used in these algorithms are: length profiles of the main river, the basin’s accumulative flow, basin slope and comparison of built DEMs. The result shows that the algorithm in which the DE (Drainage Enforcement) takes place primarily and then the elimination of ditches in the conventional way executed by some GIS software systems is the most appropriate method.Conformity of the drainage with paper maps and also the removal of digital ditches is a way that the drainage directions in the DEM point correctly to the water channel, is the main adventage of this research.

Biodiversity, which is a necessity of sustainable agriculture, can provide species that may act as natural enemies for biological control or genes for increasing crop resistance to biotic and abiotic stresses. The improvement of biodiversity by introducing crop species which have functions similar to off-farm inputs, reduces an agroecosystem’s dependency and increases its self-sufficiency and sustainability. In order to evaluate the agrobiodiversity of a wheat-cotton cropping system and its effects on ecological sustainability, a survey was conducted in Khorassan province (eastern Iran). Agrobiodiversity indicators were the growing of other crops than wheat and cotton, planting forage legumes, green manure, livestock presence and diversity in the farm.The data were collected from Neyshabour, Bardaskan and Ferdows using 518 questionnaires.Results showed that only 7.9 and 1.4 percent of farmers grow forage legumes and green manure, respectively; 78 percent of farmers grow at least one other crop than wheat and cotton while 47.5 percent of farmers have one or more kinds of livestock in their farms which are mainly considered for family consumption. Results also proved a significant correlation between all agrobiodiversity indicators with ecological sustainability in this cropping system.

Samples of Schizothorax pelzami were collected by electroshocker from Laiinsoo River (n=150) in northeastern Iran in January 1995. The growth and diets rates of S.pelzami were examined. For 30 specimens in Laiinsoo River, the length-weight relationships were estimated as W= -12.108×L3.134 (r=0.999) for females and W= -10.594×L2.796 (r=0.849) for males. Stomach contents were examined to determine the kind, number, and volume of organisms present. Classification of the stomach contents of individual fish in Laiinsoo River revealed different groups of benthic invertebrates. Chironomidae, were the most abundant benthic invertebrates among the categories of organisms collected. The Ivelev index showed that odonata, at 1; Chironomidae (Larva), at 0.6, and Simulidae (larva), at 0.5, were the most important food items for S. pelzami. The ratio of male to female for specimens caught from Laiinsoo River was 2.5:1.

The concentration of five metals, including Pb, Cu, Cd, Ni and V, in the blood serum and tissues of Stellate sturgeon was evaluated in spring and autumn during 2001-2, using Shimatsu AA 670 G Flameless and Shimatsu AA G70 Flame, according to AOAC, 1990. The specimens were caught in two important sturgeon fishery zones located in Guilan and Golestan provinces in the Southern Caspian Sea. Concentrations of the tested elements followed the sequence Cu>Pb>Cd>Ni, V in tissues, as well as Cu>Ni>Pb>V>Cd in serum. There were significant differences in the levels of these elements in the blood serum and tissues of the Stellate sturgeon (P<0.05). In this study, the relationship between the concentration of the elements and biological characteristics has been examined. The significant length- and weightdependent relationships were observed for Cd in blood serum. Only in the case of Pb in the liver were age related differences found. Only in the case of Ni in blood serum could significant differences between two selected sampling areas be detected. To our knowledge, this study provides the first extensive data of elemental accumulation in serum, liver and gill of Sturgeons of the Southern Caspian Sea.

To evaluate the distribution of clodinafoppropargyl resistant wild oat to in south western Iran (Khuzestan province), 50 fields which were sprayed with aryloxyphenoxypropionate herbicides were sampled. Those fields at which wild oat had been controlled efficiently by these herbicides were selected for the experiment. Populations (50 suspicious to resistance and 1 susceptible) were studied in a randomized complete block design with four replications in 2005. Populations of wild oat were sprayed during two- to four- leaves stage using the recommended dose of herbicide. Shoot biomass, survived plant and EWRC visual rating, were recorded four weeks after herbicides application. Longitude and latitude of different sampling locations were registered using GPS.Grouping populations using cluster analysis showed that 52% of populations were resistant, 28% were suspicious to resistance and only 18% of populations were susceptible and semi susceptible. Furthermore resistant populations were detected in all of parts of khouzestan province.