نشریه تحقیقات منابع طبیعی تجدید شونده
سال هشتم شماره 1 (پیاپی 27، بهار و تابستان 1396)

Species composition and structure of forest stands change through time due to natural and artificial disturbances. Considering the importance of plant diversity, the present study intends to evaluate changes in species composition following disturbance in a natural ecosystem in the south of Sari city, Ojasarak. For this purpose, tree canopy in 58 sample plots with 400 m2 area were randomly measured in two regions. One 1 m2 plot at the center and Four 1 m2 plots at the corners of the sampling plot were marked to measure and collect the herbal plants. To evaluate biodiversity, Shannon-Wiener and Simpson diversity indices, species richness, curves of rank-abundance, K-dominance and rarefaction were used. The results showed that except Simpson index in biodiversity indices, there is not any significant difference between indices in two natural and artificial disturbances. Based on the results of rank-abundance curve, K-dominance and rarefaction, the diversity in natural disturbance is more than artificial disturbance, but richness in artificial disturbance is more than natural one.

In order to study changes of production and utilization of Artemisia sieberi at growth season and grazing season, the site of Khoshkerood-e- Saveh ,which is indicator of steppe rangelands, was selected. To evaluate the vegetative and productive characteristics and forage consumption by livestock at different stages of plant phonology, this experiment was carried out during 2010-2012 years. Thus remaining amount of forage grazing was harvested until a month intervals, and consumption rate was determined by subtraction between harvested forage and fenced plot forage. Finally, in order to study the effect of harvest months on the production and consumption under investigation in the study area, data were analyzed. The results showed that production has fluctuated during different rainfall. Year 2011 produced more forage than the average (119 kg ha) of about 8 percent higher and year 2010 produced the lowest yield: i.e., 10% lower than the average. This species share in rangeland production was high and on average four years, about 21 percent of rangeland forage was produced by A. sieberi. In average three-year, peak rangeland production was in April (vegetation stage) and has decreased in June (vegetation stage). On average, 51 percent of production was grazed by livestock along grazing year. Greater share of rangeland forage consumed in November (seeding stage) and drying time of plant and in April At the start of vegetative growth. Artemisia almost grazed in autumn and Early Spring. Due to the considerable consumption by livestock and produce high of this species, is a good source of forage in winter pastures. According to fluctuation of production in different years, long-term average of good production is recommended to be considered in the codification of management plans.

The development of tourism in protected areas has many advantages for regional management and tourists. Therefore, identification of suitable and potential areas for expansion and development of tourism in protected areas is crucially important for sustainable exploitation of natural resources. The aim of this study was to identify suitable areas for centralized and extensive tourism of Sahand protected area by multi-criteria decision making (MCDM) method using the geographic information system (GIS). According to the effective criteria on the eco-tourism and also based on previous researchers and expert opinions, 12 criteria for a centralized resort and 11 criteria for extensive resort were selected by the Delphi method. And also analytical hierarchy process (AHP) and fuzzy method were prepared for classified maps. The classified maps included the distance maps from water sources, road, spring, river, residential areas, wildlife corridor, goat habitat and fault and height from sea level, slope, geographic direction, land flora, bedrock, and climate. Finally, the priority map of eco-tourism appropriate areas was produced using weighted linear combination (WLC) method and by applying the coefficients of the importance of each criterion to corresponding classified map. The results showed that about 7, 40, 25, 4 and 24 percent of the centralized resort area were very good, good, average, poor and unsuitable, respectively. Besides, about 43, 42, 13 and 2 of the extensive resort area were very good, good, average and poor, respectively.

In this study, the effects of climate change on desertification process in Tabas was studied using the SDSM software and long-term statistics (30-year period) of synoptic stations to predict temperature and rainfall parameters by the data of HADCM3 model for future periods (2010-2039, 2040-2069 and 2070- 2099) under two scenarios A2 and B2. In addition, this process was studied in two 15-year periods and Domarten method was also used to determine the degree of rainfall area. The results of the predictions and the observation period were compared together. Due to the significant effect of decreasing temperature and rainfall as well as drought index on the desertification process, drought indices were also determined. Results indicated that the effects of climate change on the getting worse of conditions in the area and consequently, decreasing rainfall, increasing temperature and decreasing the drought index were significant. According to the results, it can be stated that although the desertification process is affected by several factors, but in the future climate changes, there are the probability of increasing the desertification process and expansion of desert areas in Tabas, due to the change in rainfall and increasing temperature. On the other hand, because of increasing temperature and decreasing rainfall, many agricultural lands will be released, and the conditions for soil degradation as a result of increasing desert areas will increase.

The soil is the most important part of the land evaluation. Most methods of soil mapping are the timeconsuming and costly. The purpose of this study was soil parameters mapping based on geopedology method using satellite data and GIS for assessment and land use planning. First, using the geopedological method, the map of soil homogeneous units was prepared. The soil samples were taken from each unit. The soil parameters were then extracted in the laboratory. Finally, the parameters maps were prepared within GIS environment. In addition, to prepare the required maps such as land cover, canopy density, and the type of land cover were used satellite data and land data collection. The results showed that the used method using satellite data and GIS will reduce the sampling, field and laboratory works and will lead to saving the cost and time will increase accuracy.

The aim of this study was to determine the concentrations of heavy metals nickel and cadmium in muscle tissues of Liza klunzingeri in Bushehr seaport during 2017. 30 samples of Liza klunzingeri were caught completely at random from Bushehr seaport by the area local fishermen should be omitted. After biometry based on the MOOPAM procedure. The muscle tissues of the samples were separated and chemical digestion of the samples was done nickel and cadmium accumulation levels in tissues were measured using Graphite furnace atomic absorption instrument (VARIAN AA 100). Based on the results, the mean concentrations of nickel and cadmium in muscle tissues of Liza klunzingeri were 6.638 ± 0.611 and 3.201 ± 0.292 mgkg-1 dry weight, respectively. Findings of this study revealed that nickel and cadmium concentrations in edible tissues (muscle) of Liza klunzingeri captured from Bushehr port are more than the levels permitted within the standards of WHO, FAO, NHMRC and UK(MAFF).

In this research, the effects of dietary cinnamomum zelanicum (Cinnamomum zelanicum) on the chemical composition of Cyprinus carpio muscle were investigated. 240 specimens of common carp with initial average weight of 11.14 ± 1.2-12 g were seperate in four treatments of 0, 5, 10 and 15 g cinnamon powder per kg diet. Findings were done in three replicates for 60 days in 12 fiberglass tanks with capacity of 135 liters. At the beginning and the end of the experimnt, 10 specimens were selected for determination of growth indices (specific growth rate, relative growth rate, weight gain, length, feed conversion ratio, protein efficiency ratio) and chemical composition (moisture, protein, Fat, fiber and ash). Most of the growth indices including weight gain, length increase, relative growth rate, specific growth percent and protein yield ratio were significantly increased in fish fed with diet containing 10 g kg-1 of cinnamon powder (P<0.05). The survival rate of the fish was high and the highest survival rate of fish was in the treatment of 10 g kg-1 cinnamon powder. Analysis of chemical composition showed that the highest mean protein and moisture content of the treatments were in the treatment of 10 g kg-1 of cinnamon powder and the highest mean of muscle fat and carbohydrate in the control treatment. There was no significant difference between mean of fiber and ash content among treatments (P> 0.05). According to the present results, the addition of 10 gr cinnamon per kg diet is recommended for common carp.