ECOPERSIA
Volume:3 Issue: 2, spring 2015

Water erosion causes a series of on-site as well as off-site damages and problems on natural ecosystem. These damages include soil and nutrient loss and finally loss of productivity which causes costs to the society. So, this study attempts to quantify the economic value of soil productivity conservation as one of the important functions of rangelands vegetation and its economic cost by productivity losses. The soil loss amounts were obtained from integrated Geographic Information System (GIS) and map of erosion vulnerable areas using RUSLE model. Supplementary data such as soil nutrients (NPK) valuated from the measurement plots of a portable rainfall simulator (E65). Field plots were constructed to measure soil nutrients and soil loss from different soil types with different resistance to erosion. Rainfall simulation was carried out in three sites on the basis of geology map and different resistance to erosion. Nine experimental unit plots (1*1 m) were used to correlate nutrient loss to sediment losses. Assuming that nutrient loss by erosion could be replaced by fertilizers, economic cost of major nutrients estimated by market prices of fertilizers. Results showed that mean annual soil loss using RUSLE was 27.44 t ha-1 y-1 ranging from 0.0 to 996.06 t ha-1 y-1. Also, 114.17 kg ha-1 y-1 of N, P, K elements were lost in 2010 due to soil erosion in the degraded rangelands which costs (738944 Rial) 71.5 US$ ha-1y-1. Total economic cost of soil nutrient loss in 94978.6 ha of the rangelands of Nour-rud watershed basin, was estimated 70×10^9 Rial (6.8×106 US$). The maximum annual cost of soil nutrient loss was estimated in the "TRujs" geological formation (1.23×106 US$) consisting of "gray shale, silt, sandstone, conglomerate" and the least cost belonged to the "Jl1" geological formation (0.916*106 US$) which consists of "thin gray dolomite limestone". In economic terms there was a direct relationship between soil nutrient loss and its economic cost.

Land-use planning is a science that determines the type optimum of land-use through studying the ecological characteristics of the land as well as its socio-economic structure. The primary objective of this study is to evaluate the land-use and natural resources for future sustainable land planning using GIS. In this study, the Makhdoom’s systematic method was used to analyze the ecological and resources maps of the study area. At first, ecological capability maps of different land-uses including forest, agriculture, rangeland, environmental conservation, ecotourism and development of village, urban and industry were developed by overlaying geographical maps in GIS for the township. The final step of this study was the prioritization of land-uses considering the ecological and socio-economic characteristics of the study area using a quantitative model. The results indicated that the maximum area of proposed use was 39.30 % that was related to range and dry farmingand minimum area of proposed use was 3.3 % which was related to irrigation agriculture with range.

Epizoochory and endozoochory are well-known mechanisms by which seeds are dispersed by animals. Since, livestock gather around the watering-points to rest and drink, we expected to find that seeds would be frequently moved to the areas surrounding watering-points, resulting a higher soil seed density (and diversity) closest to the water. We investigated this issue by assessing soil seed bank density and composition along a distance gradient from the water and compared them with an ungrazed-control area in 2010. Therefore, three watering-points were selected in a dry rangeland of Kahnuj, Kerman Province, Iran. Soil seed bank characteristics were measured at eight distances with different intervals from the watering-points (totally 80 sampling points) and in an ungrazed area (30 sampling points) after seed dispersion in autumn. The results showed that in spite of the assumption, soil seed density and similarity between the soil seed bank and above ground vegetation increased with distance from the watering-points. A clear trend was not detected for the diversity of soil seed bank with distance from water source. Our findings suggested that the restoration of degraded sites could not rely on soil seed bank. Areas surrounding watering-points, where soil seed losses are potentially higher than those at greater distances from water source, should be given more attention for conservation by the rangeland managers.

The present study aimed to assess pure planted species (i.e., Alnus subcordata L., Poplus deltoids L., Taxadium distichum L. Rich) and a mixed natural forest (i.e., dominated by Quercus castaneifolia C. A. Mey. - Carpinus betulus L. - Parrotia persica C. A. Meyer) on basis of some soil quality indices in Mazandaran Province, northern Iran. Sixteen samples per stand were taken from the top 10 cm of soil and bulk density, texture, water content, pH, EC, organic C, total N, available nutrients, earthworm biomass, microbial respiration, fine root biomass with organic C and total N of litter layer were determined. Nine criteria (i.e., silt, EC, K, Ca, Mg, microbial respiration, fine root biomass, nitrogen mineralization and litter C/N) were selected according to Principal Component Analysis (PCA) as Minimum Data Set (MDS). The analytical hierarchy process (AHP) method was employed to assign the data integration in an index. The calculated overall priority based on nine criteria, showed that the A. subcordata forest type had higher ecological potential (0.370) compared to the other stands. Whereas, P. deltoids mixed natural forest and T. distichum with ecological potential of 0.295, 0.213 and 0.122 had next priorities, respectively. As a conclusion, the N-fixing species, A. subcordata, was found more efficient in improving soil quality in degraded forest regions

TheChah Nimeh reservoirs of Sistan is as one of the main water sources of Zabol City used for drinking, agriculture, industry and livestock purposes. This study aimed to determine the contribution of the natural and concentration factors of heavy metals such as Cd, Pb and Cu in sediment of Chah Nimeh of Sistan. The concentrations of heavy metals in surface sediments were studied in six stations during 2013. To determine the concentration of the heavy metals atomic absorption spectrometer (Contr AA 700) was used. Sequential extraction analysis was applied based on the share of natural and concentration factor sources of heavy metals. Sequential extraction analysis showed that a considerable part of the Pb (63.67%), Cd (55.17%) and Cu (57.17%) were from natural sources. The highest concentrations of Cd and Pb were 0.81 and 5.57 mg kg-1, respectively, obtained in station one and the maximum Cu concentration was observed in station five (37.8 mg kg-1), while the lowest concentration of Cd, Pb and Cu were 0.34, 3.95 and 31.4 mg kg-1, respectively.

Shahrechay Dam is located at 12th Km of Shahrechay River in Urmia. This study was conducted for a year (Spring to fall, 2007) to identify different species of benthic organisms in the dam. Considering the relevant topographic status like the local depth and water speed, 6 sampling stations were chosen and sampling was done in shallow locations of the river by means of superficial method. In this study, 2 phylums, 2 orders, 13 families and 21 species of benthic organisms were identified in Shahrechay Dam Lake. The results indicated that the highest species diversity belonged to Ecdyonuridae family (Eperous Genus). In terms of frequency, it belonged to Tibuficidae (Tubifex Genus), with 43%, 23%, and 11% ratios for spring, summer, and fall, respectively. The final result of the research demonstrated the poverty of lake bed from view of the benthic quantity and density. Therefore, the Shahrechay Dam was not a suitable candidate to develop fishery’s purposes, especially releasing and growing Cyprinidae fishes and other benthos-feeder aquatics.

The pollution of aquatic ecosystems may affect natural reproduction of fish populations by decreasing the fertilization efficiency. Among the various sources of pollution, heavy metals are important group, being found in both freshwater and marine environment. The present study investigated changes of sperm characteristics of Caspimyzon wagneri when exposed to Manganese (Mn). Spermatozoids were exposed to 0 (control), 0.01, 0.1, 1, 10, 100 and 1000 mg l‑1 of Mn, duration of sperm motility and percent of motile sperms were measured using a light microscope and digital camera as a semi-quantitative method. Total duration of spermatozoids motility decreased with increase of Mn concentration in all treatments. This study indicated that Mn could seriously affect the reproductive success of the Caspian lamprey in a polluted environment through decreasing the duration of spermatozoid motility and possibly fertilization and hatching rates. Hence, contact to this metal could decrease the survival rate of this endangered species, especially during the reproduction.