فهرست مطالب

Environmental Resources Research - Volume:3 Issue: 1, Summer - Autumn 2015

Journal of Environmental Resources Research
Volume:3 Issue: 1, Summer - Autumn 2015

  • تاریخ انتشار: 1394/09/21
  • تعداد عناوین: 7
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  • F. Setayeshi*, H. Varasteh Moradi, A. Salmanmahiny Pages 1-13
    Habitat destruction is one of the main factors threatening species so that until 1980 about 30 percent of species became endangered because of degradation and destruction of wildlife habitat. Birds were surveyed in four different patch sizes (<1 ha, 1-10 ha, 10-25 ha and >300 ha). Environmental variables, including forest cover type, characteristics of the structure and complexity of vegetation and those of landscape as well as the number of birds were recorded within a 25-m radius of each of 74 sampling points. Results showed that habitat variables including vegetation type, number of snags, number of logs, number of trees with dbh 0- 20, 20-50, 50-100, 100300 cm and basal area were the most important variables affecting the presence of birds in the study area. The results of this study highlighted the importance of forest patches and their attributes in conservation and enhancement of bird’s habitat as well as in conservation of biodiversity of forest ecosystems.
    Keywords: Birds, Forest patches, Conservation, Gorgan1
  • A. Mohsenpour Azari*, M. Seidgar, F. Mohebbi Pages 15-26
    Aras dam is one of the important water reservoirs in Iran with a total area of nearly15000 ha. Population dynamics including length and weight composition, fecundity, sex ratio, molting time, and reproduction and capture times of freshwater crayfish (Astacus leptodactylus) of Aras reservoir was investigated during 2012-2013. The results revealed that the mean total length and weight of captured crayfish were 106.26 ± 12.89mm and 38.79 ± 15.54g, respectively. The largest crayfish had 171mm length and 216g weight. Mean number of ovarian and pleopodal eggs were 286 ± 82 and 246.31± 80.4, respectively (P≤ 0.05). In this study, male to female ratio was obtained as 1.21: 1. The male molting at 16 º C was started from late April and ended in late May, when the water temperature reached 18 º C. The second molting of males and the first molting of females occurred simultaneously at 18 º C water temperature in September. Matting of Astacus leptodactylus was started from November and continued until May. Harvesting period was from May to late November. The results showed that the number of eggs were variable (from 200 to 400 eggs) and depended on spawner size, environmental condition and available food. Besides, crayfish with higher lengths and weights had increased fecundity with a direct positive correlation. A ban on fishing during the reproduction season, use of appropriate nets and proper management should be performed to preserve the stocks of this species.
    Keywords: Freshwater crayfish, Astacus leptodactylus, Fecundity, Aras dam1
  • A.R. Kaveh*, K. Shahedi, M. Habibnejad Roshan, J. Ghorbani Pages 27-45
    In this study, spatio-temporal variations and prioritization of pollution sources of 12 surface water quality parameters in Talar Watershed, Iran were studied at six stations during 2003-2011 using One-way ANOVA, Principal Component Analysis (PCA), Cluster Analysis (CA) and Analytic Hierarchy Process (AHP) techniques. The results of One-way ANOVA showed that spatio-temporal variations had significant influences on water quality parameters in the study area. We observed that surface water quality parameters increased during 2003-2011 and Khatirkuh-Doab station had the maximum value and PolShahpour had the minimum value of surface water quality parameters. PCA results indicated that the first three components at Kiakola, PolShahpour, PolSefied-Talar and Paland stations; the first two components at Shirgah-Talar station; the first four components at KhatirkuhDoab station (with the exception of the year 2006-2007 with one first component) first two components, explained spatio-temporal variation of surface water quality parameters. CA results also showed that Kiakola and Shirgah-Talar stations are placed in the first cluster, PolShahpour and Paland stations are set in the second cluster, Khatirkuh-Doab station is put in the third cluster and PolSefied-Talar station is located in the fourth cluster. The results of AHP showed that among pollution sources (lithology, land use change, land use type and mining of river bed) of surface water quality in this watershed, lithology and mining of river bed had the maximum and minimum impact on surface water quality, respectively.
    Keywords: Pollution sources, Spatio, temporal variations, Surface water quality, Talar watershed
  • S. Sasanifar *, M. Namiranian, N. Zargham Pages 47-57
    In forest management, determining characteristics of trees is essential for assessing tree volume and providing other mathematical equations. In this study, the characteristics of 256 trees including stump diameter, diameter at breast height, total height, crown height, height of trunk with and without branch were measured in an even-aged Fraxinus stand at Chelir part of Kheyroud Forest in north of Iran. Results showed there are significant statistical correlations among various characteristics of Fraxinus excelsior trees, and mathematic-statistical equations were established among these characteristics. We found the incremental power relation between stump diameter (dst) and diameter at breast height (d), which can be used for estimating diameter at breast height of cut trees. Also, another equation was established between diameter at breast height and total height (ht) which is used for estimating total height of those trees for which diameter at breast height is available. An incremental logarithmic relation was found between diameter at breast height and crown height (hc) and an inverse one between diameter at breast height and trunk height (trh) for this species. Also, a sigmoid relation was found between stump diameter and total height. Results implied that trunk height decreases and crown height increases as total height increases. Trees with higher diameters have high height of trunk without branch. The relationship between Slenderness coefficient (h/d) and diameter at breast height of the trees was found to be a power type.
    Keywords: Even, aged stand, total height, without branch trunk height, power relation, sigmoid relation, inverse relation1
  • M. Karimi, K. Shahedi, M. Byzidi Pages 59-74
  • B. Rasouli*, B. Amiri Pages 75-83
    Halophytes, as integral parts of many marine, coastal and terrestrial ecosystems, can play an important future role for biosaline agriculture, forage production and habitat restoration. There is currently a lack of public awareness and scientific documentation regarding nutritive value of halophytes. The aim of this research was to determine nutritive value of native halophytes of Iran. Seven saline indicator species of Iran including Halocnemum strobilaceum, Halostachys caspica, Seidlitzia rosmarinus, Salicornia herbacea, Alhagi persarum, Salsola regida and Atriplex leucoclada were sampled at three phenological stages (vegetative, flowering and seed ripening). Then, the plants were powdered and six quality traits, Crude Protein (CP), Acid detergent fiber (ADF), Moisture, Metabolizable Energy (ME), Ash and Dry mater digestibility (DMD) were determined. ANOVA results revealed that there were significant differences among all species and phenological stages. ME, DMD and CP decreased in all the species in three stages, but ADF changed significantly in seed ripening stages in H. strabilaceum (20.63), S. rosmarinus (17.61 %) and H. caspica (17.4 %). The difference was not significant in flowering (32.56%) and seed ripening (31.66 %) stages for A. persarum. Increasing of ash and moisture content in flowering stage in succulent halophytes helps them to tolerate salinity. Due to less fiber and more CP, ME and DMD, S. regida has the highest nutritive value and A. leucoclada has the lowest value. Also, late vegetative or early flowering stages are the best time of forage quality according to these traits.
    Keywords: Nutritive value, phonological stage, Halophytes
  • A. Kornejady*, K. Heidari, M. Nakhavali Pages 85-109
    This research is focused on developing landslide susceptibility, risk and management zonation map in the Ilam dam basin, in the west of Iran. For this purpose, all existent landslide locations in the basin (50 landslides) were registered using GPS device and 70% of these points (35 landslides) were used for landslide susceptibility modeling and the rest (15 events) were used to evaluate the model. In order to prepare landslide susceptibility map, eight key factors were used for landslide occurrence such as distance to fault, distance to stream, distance to road, lithology, land use/cover, slope percent, aspect and precipitation derived from the spatial database in Arc GIS 9.3. A hybrid method of logistic regression and Analytic Hierarchy Process (AHP) were respectively used to determine the weight and rate of different factors and their classes. After applying rate to classes of parameters using the AHP method, landslide susceptibility map was prepared by means of logistic regression analysis tool in IDRISI software. The model accuracy was assessed by receiver operating characteristic (ROC) indicator and the pseudoR2 and used as a basis for risk mapping. The landslide risk map was prepared using Varnes equation through combining three maps of susceptibility, vulnerability and the elements at risk. In order to provide the landslide management map, multi-criteria evaluation (MCE) method was used incorporating susceptibility and risk variables. The results suggest the logistic regression and AHP model has high accuracy (ROC= 81.2%, pseudo-R2= 0.32). We found that 39.84, 72.45, and 76.33 km2 of Ilam dam basinare located in the high and very high classes of lands lide susceptibility, risk and management maps, respectively.
    Keywords: Landslide Zonation, Analytical hierarchy process, Logistic regression, Varnes equation, Multi, criteria evaluation