JWSS - Journal of Water and Soil Science

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Due to the feeding on prickly shrub of Astragalus adscendes by an insect (Cyamophila dicora Loginva), a kind of the manna named Gaz-angubin is produced which it’s harvesting has a long history in Isfahan province. This manna is exclusively produced in Isfahan, Iran. In this research, a map of spatial distribution of this prickly shrub was provided. By random-systematic sample of line transects, biological criteria such as insect density, canopy coverage, branch and the soil moisture were measured. Multiple linear regression and nested design were used to analyses the response and predictor variables. The results indicated that the prickly shrub of Astragalus adscendens occupied the wet parts of mountainous areas of Isfahan and density of insect is highly related to the age, canopy coverage and soil moisture. By increasing the age of prickly shrub, the densities of insect are also increased. Regression analysis showed that the age of plant are more important in two areas of Kloseh and Lashokhm, while in Dareh-sibe area, soil moisture and the moisture of branches are more important. In other words, when the moisture is enough (e.g. Kloseh and Lashokhm areas), the age of plant has the paramount effects on insect density but when the area was suffered from drought, branches and soil moisture are more important.

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Population of Persian gazelle has been declining in recent decades and as a result, this species was added to the IUCN list of threatened species in 2006. However, there is paucity of ecological data about this species within its range. Mooteh Wildlife Refuge is one of the best habitats of Persian gazelle in Iran where one of the biggest populations of this species live. Habitat selection by threatened Persian gazelle was studied in three seasons in Mouteh wildlife refuge. Habitat use was related to plant communities and plant vegetation variables using clearance transect pellet group counts carried out every 45th day. The effects of water resources and disturbance by man and livestock were controlled. Habitat selection was significantly different between seasons and plant communities. Salt bearing clay soils with a high diversity of holophyte plants were mostly used particularly over winter, while Artemisia- Zygophyllum community was avoided in all seasons. Minimal models resulting from multiple regression retained a number of vegetation variables in each season including a negative effect of Tamarix sp. and Alhaji camelorum and a positive effect of Halocnemum strobilaceum and Salsola dendroide in autumn and winter. It is concluded that selection of habitat by Persian gazelle changes by seasons and that salt-bearing soils and Artemisia-Salsola community are the most important habitats for gazelles in Mouteh Wildlife Refuge.

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Reference evapotranspiration (ET0) is a necessary parameter for calculating crop water requirements and irrigation scheduling. In this study, a method was presented as ET0 is estimated with NOAA satellite imagery in the irrigation network. In this method, a pixel from a set of pixels within the irrigation network was chosen with the highest vegetation index, and its surface temperature (Ts) with extraterrestrial radiation parameter (Ra) was used as inputs of the model. The M5 model tree for converting Ta and Ra to ET0 was used as input variables. In this research, Gazvin irrigated area was selected as a case study. A total of 231 images of NOAA satellite related to irrigation season of the study area were used. The results obtained by the M5 model were compared with the Penman–Monteith results, and error values were found within acceptable limits. The coefficient of determination (R2), percentage root mean square error (PRMSE) and the percentage mean bias error (PMBE) were found to be 0.81, 8.5% and 2.5%, respectively, for the testing data set.

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The aim of this study is to prepare the groundwater spring potential map using Weight of Evidence, logistic regression, and frequency ratio methods and comparing their efficiency in Chehlgazi watershed, province of Kurdistan. At first, 17 effective factors in springs occurrence including geology, distance to fault, fault density, elevation, relative permeability of lithological units, slope steepness, slope aspect, plan curvature, profile curvature, precipitation, distance to Stream, drainage Stream density, Sediment Transport Capacity Index (STCI), Stream Power Index, topographic wetness index (TWI) and land use/land cover (LU/LC) were selected. The validation processes of methods were conducted by relative performance characteristic curve (ROC). The area under an ROC curve (AUC) for the weight of evidence, logistic regression and frequency ratio was 85/8%, 79% and 89%, respectively. The results showed that all methods are suitable estimator for mapping the groundwater spring potential in the study area. But the frequency ratio method with the most amounts is the best method to produce and map the groundwater spring potential. Also, validation of the mappings based on the percentage of pilot springs, training springs and all springs showed that the logistic regression, WoE and frequency ratio, with 45, 56 and 45 percent of spring occurrence on the high potential classes respectively, had the highest validation.

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