نشریه اکوبیولوژی تالاب
سال هشتم شماره 2 (پیاپی 28، تابستان 1395)

Temperature and precipitation are the main components of climate forming which their variation can change the climate structure of each site. This study investigated the temporal and spatial variations of temperature and precipitation in the Karkheh Basin, located in the West of Iran. For this purpose, after checking thehomogeneity and accuracy of data, 22 synoptic and meteorological stations over the 1971-2011 periods were selected. The objective of this study is evaluating the changes in temperature and precipitation time series by Mnn-Kendall, Spearman tests and Sen’s slope estimator. Results showed significant increasing and decreasing trends in the annual temperature and precipitation, respectively, with significant levels of 1 and 5 percent for most of the stations. The magnitude of the significant positive trends of annual temperature changed from (+) 0.12 °C/decade at Khrromabad to (+) 0.61 °C/decade at Kermanshah. The maximum and minimum annual precipitation decreasing trend was observed at Ghourbaghestan station located in the Kermanshah province and Dehnoud station, with slope of (-) 8/77 mm/year and (-) 1/27 mm/year, respectively. In special pattern, almost all stations in the eastern part of the Karkheh basin showed non-significant trend in precipitation. The most significant decreasing changes was observed in the West and South parts of Karkheh basin although the decreasing of precipitation in central and eastern parts was seen but this trend was not significant. Generally, the detection trend changes, except for exceptional cases, are consistent with recent findings of global studies.

Evapotranspiration is one of the parameters affecting the watershed water balance and as a basic parameter in hydrologic cycle.Being a function of different metrological parameters and their interactions, evapotranspiration is a complex, nonlinear phenomenon. Preprocessing input parameters to select appropriate combinations is complex when modeling nonlinear systems. Therefore, in this study artificial neural networks MLP, FF and MNN for evapotranspiration modeling and in this context of MATLAB software was used. By using the climatic data in Ahvaz climateyears 1988-2014, the average values of reference crop evapotranspiration was calculated by FAO Penman Montith standard.Then these values was used as output targets of different networks with conventional structures defined and trained. Eventually capability of estimation of evapotranspiration network by using the part of the data network is not used in the design or training, was evaluated. With reviews was conductedshowed who using only the daily average temperature as an input parametercan be the reference evapotranspiration using three types accurately estimate network. Also compares the results of three network tests showed that FF and MLP networks to MNN for determining reference evapotranspiration are higher accuracy.

The aim of this study is investigation of environmental threaten factors of the forests located in the west of Karkheh river in Ahvaz based on Multi-criteria decision-making model in the area of bitQeshm and Shenin Hosein. The region is 40 km away from the center of Khozestan; it is located in the north of Ahvaz, south of Shoushtar and the west side of Karkheh River. The surface area of the region is 4086.6 hectares. It has unique ecological features and influenced by the negative influencing factors because of improper activities of local communities. In this study, Delphi technique was used for identifying existing risks in the region, then 21 risks were identified and 15 of these risks were left as the final risks in the group of environmental risks. In the next step, Analytical Hierarchy Process (AHP) was used for analyzing and prioritizing the identified risks. In this study, the risk factors evaluated using the severity of the impact, occurrence probability and sensitivity of the receptive field. Results showed that the most threatened factors are economical and cultural factors. In the category of economical factors, poverty and unemployee with the weghit of 0.554, shortage of forest warden the weghit of 0.328 and in cultural category; Lack of knowledge of the indigenous peoples of environmental values with the weghit of 0.302 were the most parameters respectively.

Urmia Lake is one of the biggest over-saturated salt lakes of the world. It is located at the northwestern part of Iran. The temporal change in the concentration of Artemia fecal pellets can be used as an indicator of lake level changes, paleoclimate and therefore regional hydrological changes. In this study basis on the previous data collection, 28 sedimentary intact cores with a maximum depth of 10 meters and a total of more than 200 meters were sampled from the lake sediments by Gouge Auger coring method. Sedimentary facies were separated based on color, grain size, existence of Artemia fecal pellets, sedimentary fabrics and the type of evaporative minerals. With regard to vertical sedimentary facies (from surface to sub-surface areas) changes and the results of elemental analysis, geography, climatic conditions and lake water level fluctuation were re-constructed. Facies belong to Lake, Lagoon, River and Playa environments. According to the age measurement by isotope carbon-14 method, deposition rate is between 0.7 to 0.8 mm per year, but this rate was varied in different parts of the lake (1.0 to 1 mm per year), this amount was maximum in river delta (mostly west of lake). Artemia fecal pellets constitute about 5-35% in average and 90% in maximum of the deposits. Fecal pellets of Artemia that formed of aragonite prismes were one of the biochemical sediments of the lake that mostly intact pellets or crushed cream color and black pyrite pellets are observed. Finding Artemia fecal pellets as old as early Holocene, showing that this Crustacean lived in the lake since at least the beginning of the Holocene. Sediments study shows that the organic content of fecal pellets gradually diminishes down the cores. Increase in amount of fecal pellets was match with wet interglacial periods in South Asia and Africa (4 to 10 thousand years ago). These periods also shows wet conditions with sediment geochemistry studies. The Urmia lake level fluctuations can be a major factor in controlling the high temporal variations in the abundance of Artemia fecal pellets. However, caution should be taken in the interpretations as other environmental factors, such as temperature changes, water circulation, taphonomic history, etc.

Protected region of Margoon with area of 10000 hectar and mild weather with and different variety of plants and animals is one of the especialest protected places of Fars province; in other word, this region is very suitable for reviving the Ecosystem of Fars province. The objective of this research is to evaluate the ecological conditions of protected region of Margoon in order to developing the Ecotourism activities. The method of gathering descriptive-analytic data was done by library and documentary studies and in field data analysis. To achieve the objectives of this research the method of SWOT strategy was used base on the specifying the advantages, disadvantages, opportunities and threads and this method is weighted by the Analytic Hierarchy Process (AHP(.The present study which was conducted in 1391 Indicates that Margoon area had 16 domestic factors that weight rating of internal factors (6/55), the number of external factors was 15 factors and according to the assessment conducted weight score external factors (6/9). The number of external factors was 15 factors, and according to the assessment conducted, weight rating external factors (6/9) due to these conditions rating total factors are almost equal. According to the evaluation conducted, situation of Margoon Waterfall is in average condition. According to this research, the most important strategies to meet strengths and weaknesses, threats and opportunities have presented in the SWOT matrix. On this basis necessary investments in Section ecotourism and create ecotourism sites in surrounding area of Margoon waterfall and perform correct management and provide the necessary facilities and services, can be expanded the ecotourism in the area.

This study carried out in 2013 to investigate the effects of wastewaters output of 1500 pisciculture ponds with an area of ​​2,000 hectares in region of Noor Ali (rural areas of central township shushtar in Khozestan province), which totally had 23 Large drains of discharging wastewater, on characteristics and quality of Gorgor river water located between the city of Shooshtar and Ghir dam (at 55 km from the North of Ahvaz). The qualitative and quantitative data were extracted and examined after identifying all major pollutant sources. Reducing dissolved oxygen curve from 7.07 Mg/L to 3.27 Mg /L represented that the water pollution due to the wastewaters of pisciculture ponds into the Gorgor River and the gradual rise of dissolved oxygen to the value of 4.03 Mg/L in the river downstream suggested the river self-refinement and showed that the reduction of pollution load. In general, the effects of pisciculture ponds wastewaters on the quality of the river were quite evident at different intervals, and the minimum critical time (tc), the critical depletion of oxygen (Dc) and its place at the downstream of the discharge point (X) were obtained as 2.64 d, 5.2 mg/L and 45.619 km, respectively. However, according to the river self-refinement capacity in the last station at the downstream, a relatively acceptable quality will be resulted. Finally, the Gorgor River water quality improvement depended on proper management of water waste due to various applications and reduced pollution load.

Wetlands as one of the most valuable ecosystems exposed to heavy metal pollution. In recent years, many researches were performed to find a method to remove heavy metals from the environment. Phytoremediation technology has received increasing consideration owning to its characteristics including low impact and cost and environmental friendly nature. This study aimed to determine capacity of Taxodium distichum bioremediation of tree species in environments wich contaminated with heavy metals of lead and cadmium, in a completely randomized design with 4 treatments and 3 replications was used. The results showed that the highest concentrations of these metals were observed in the leaves, stems and roots, 150 and 400 mg kg-1 of cadmium and lead in 18.6, 35.33 and 89.06, cadmium and 23.4, 32.84 and 94.53 mg kg -1 lead respectively. The highest accumulation of metals was underground plant organs and the elements, reduced, in leaf> stem-branch> root respectively. That can low the mobility of the underground organs to shoots. Aaccording to the results it can be concluded that Taxodium distichum is resistant to high levels of cadmium and lead and be able to accumulate these elements in different organs. This plant were suitable for phytostabilization of studied elements with TF>1, and Use of Taxodium distichum as a accumulate plant of metals under study suggested.

The goal of this study was evaluating of the effects of inulin and herbal additives (Savory and Onion) on growth performance, feeding indices, body composition and activity of digestive enzymes (Lipase, Amylase and Alkaline phosphatase) in the juveniles of the common Carp (Cyprinus carpio). In this study 150 young carp fish with initial average weight of 20.0 ± 0.08 g were fed in fifteen groups of ten (containing a control group and four other groups with three replicate) with different experimental diets for 45 days. control group was fed with basal diet only (without inulin, savory powder and onion) and the diet of treatment inulin contained 1% inulin, treatment savory; 1% savory powder, treatment onion; 1% onion powder and treatment savory-onion; mixture of 0.5% savory powder and 0.5% onion powder. Experimental fish were fed to satiation triple daily. At the end of the period, growth performance (Final weight, weight gain, specific growth rate) and feed utilization (food conversion ratio, feed efficiency, protein efficiency ratio) were not significantly different compared with control group (p>0.05), but daily feed (3.43± 0.09) and protein intake (1.3±0.06) respectively were significantly increased in fish fed by savory compared with control group (2.49± 0.17) and (0.97±0.07) (p<0.05). On the other hand, digestive enzymes activity in different treatments was not significantly different compared with control group (p>0.05). But they have significant effect on the body composition (p < 0.05). So, the maximum amount of protein was observed in herbal treatments containing savory (60.43 ± 0.25) and onion (61.19 ± 0.06) which showed significant different compared with control group (58.39 ± 0.32) (p<0.05). Basis on the results, the use of 1% savory or onion powder is recommended for improving body composition of juvenile carp.