ECOPERSIA
Year:2016 | Volume:4 | Issue:2 |Papers Count:7

The effect of forest roads on the extent and type of fire damage occurred in forests and rangelands of the Neka County in Mazandaran province was investigated. For this purpose, all fire spots, stand number, percentage and type of injury and damage to tree species, and average diameter at breast height (DBH) were noted with 100% inventory; area and geographic location of access roads were determined using GPS. The results showed that distance from the main access road had a significant correlation with the area of fire spots, but no significant correlation existed between the distance from the strip roads, skid ways, town of Neka and the area of fire spots. The factors influencing fire severity were analyzed using the stepwise regression model. Model also showed that just the distance from the main access road affected the area of fire spots. For every one meter increase in the distance from the main access roads, the area of fire spot was increased by 1.545 m2. Further, the extent of fire can be controlled by reducing the distance from the main access roads.

The aim of the study is the classification of landform based on elevation, slope, relief and curvature inputs (old method) and topographic position index (TPI) (new method) in the south of Bojnoord. The input data for the two methods is a digital elevation model (DEM). The results of topographic position index (TPI) model showed that most area of landform were covered by class 5 (plains small) and the lowest area of landform was covered with open slope (class 6) (<0.1%). The results of landform classification using elevation, slope, relief and curvature showed that the upper terraces (shoulder) were located in the many parts of the study area (green color). Plateau (back slope) landform was located in center, some parts of the west and south of the study area. In general, with increasing slope and elevation different types of landforms occur. Thus slope, elevation, relief and curvature are effective in preparing the landform classification map. The comparison of the two methods showed that the TPI method was more accurate because the method revealed more details.

The adequacy of the SWAT model in the estimation of runoff, sediment yield and nitrate loss in the Gorganrood watershed was tested, using the existing spatial database as the primary data. The model was then executed for a 31-years’ time period. In combination with the SWAT model, the Sequential Uncertainty Fitting Program (SWAT-CUP and SUFI-2) was added used to calibrate and validate a hydrologic model of the watershed. The obtained values at 14 stations were between 0.48 to 0.83 for NS and 0.58 to 0.90 for R2, respectively. The results showed that nitrate loss was higher in cultivated lands, and in the loess deposits. The maximum amounts of runoff and sediment yield were largely produced in steep areas of the watershed, where dry farming was practiced. In general, the results showed that SWAT could be a proper tool for simulating runoff, sediment yield and nitrate loss into the river.

The effects of dominant shrub species on soil organic matter (SOM), including total soil carbon (SC), total nitrogen (N) and particulate organic matter (POM) were compared in three stands differing in the type of shrub species, i.e. Astragalus microcephalus (shrub), Pteropyrum aucheri (shrub) and Prangus uloptera (non-shrub).The stands were located in arid grasslands of north-western Iran. For this purpose, 18 soil samples from each stand were systematic-randomly collected (by auger) from each depth of 0-15cm and15-30cm, along 6 transect in each stand. The results showed that the stands with the highest abundance of P. aucheri and A. microcephalus had the highest values for SC (0.99% and 0.98%) in both depths, and the highest values for N (0.13% and 0.12%), respectively. The highest POM percentage for carbon (0.24%) and nitrogen (0.03%) were observed in the stands with the highest abundance of A. microcephalus. The proportion of micro-aggregates (28.48%) was significantly higher than macro-aggregates (20.46%) in the upper soil layer of the stand with the highest abundance of A. microcephalus as compared to the others, while no significant difference detected in micro- and macro-aggregate contents of the lower soil layer between the stands. Therefore, the type of shrub species in the grassland communities had important effect on soil organic matter.

The runoff generation and soil erosion in the Kechik Watershed, Golestan Province, was assessed, using a designed and constructed portable rainfall simulator. Treatments were applied on different land-uses, slopes and aspects as the most influential factors. Results showed that land-use significantly affected runoff generation (13.35 l, 6.9 l, and 4.12 l, respectively for agriculture, forest and rangeland uses), however slope (7.7 l for Class I; 9.23 l for Class II) and aspect (8.52 l for the northern aspects; 8.32 l for the southern aspects) did not have significant influence. All factors, significantly altered sediment concentration (Agriculture 9.6 g l-1, forest 8.24 g l-1, and rangeland 5.26 g l-1; slope class I 6.6 g l-1 and slope class II 8.7 g l-1; northern aspect 8.7 g l-1, and southern aspect 6.9 g l-1). Agricultural fields generated the highest runoff and sediment under simulated rainfalls. Rangeland and forest did not have significant runoff generation and sediment concentration. Results showed that land-use management, especially in terms of agriculture, could not only hamper current erosion, but reduced further advancement of this encroaching phenomenon.

The total concentration and percentage of heavy metals content in the sediment of Hashilan wetland, Kermanshah province, was assessed in summer 2015. The total concentrations of Cu, Pb, and Fe were around 18.57, 6.95 and 379.24 mg g-1, respectively. Successive extractions of the samples showed a decreasing trend as follows: residual>organic matter>iron and manganese oxides>exchangeable parts. The comparison of the total metal concentrations and SQGs and NOAA standards proposed high concentrations of Pb and Fe contents, while RAC suggested that Cu, Pb, and Fe had posed a low-moderate risk, low risk and no risk to the system, respectively. Furthermore, the results showed that the most common sources of Pb and Fe were natural while sources of Cu was anthropogenic. Continuous monitoring of the wetlands, particularly water inputs are recommended.

The antibacterial and antioxidant activities of methanol and acetone extracts of three marine algae, including Hypnea hamulosa, Gracilaria corticata and Enteromorpha intestinalis were investigated. Antioxidant activities were determined by means of total antioxidant capacity, total phenolic compounds, DPPH radical scavenging activity and ferric reducing antioxidant power. Antibacterial activity was determined using a paper disc diffusion method against pathogenic bacteria, including Listeria monocytogenes, Escherichia coli and Bacillus subtilis. Acetone extract of E. intestinalis showed the highest antioxidant activity and contained the highest phenolic compounds. The highest percentage of DPPH radical scavenging activity was observed in the methanol extract of H. hamulosa (p<0.05). The highest ferric reducing antioxidant power was observed in the methanol extract of Glacilaria (p<0.05). The strongest inhibition (p<0.05) against L. monocytogenes was shown by the methanol extract of E. intestinalis and the highest inhibition against B. subtilis and E. coli was observed in the acetone extract (p<0.05). In conclusion, E. intestinalis extracts showed favorable antioxidant and antibacterial activity suggesting its application in food and pharmacological industries.