مجله مدیریت بیابان
پیاپی 3 (بهار و تابستان 1393)

Growth of human population and increase in using of fossil fuel, cause to increase of greenhouse gases concentration such as atmospheric carbon dioxide over recent decades. In this study, the role of Atriplex canescens in carbon sequestration of experimental rangeland station of Nodehak in Qazvin province was investigated. The main treatment applied in a split plot design using the randomized completely blocks including two densities of 2×2 m and 4×4 m. In each treatment, four pruning heights consisting of without pruning (control treatment), completely pruning, pruning in 20 cm and 40 cm above ground. The carbon amount was measured for above and underground biomass and pruning heights, separately. The results showed that mean carbon amount in above and underground biomass per area unit in 2×2 m

Water resources management especially for groundwater resources is a very important task in arid and semi-arid regions. Over last decades, because of various natural and anthropogenic factors, critical condition and declined groundwater level have been reported in most regions of the country. With regard to importance of this issue variation pattern of groundwater level in Garmsar plain was assessed using the best geostatistics estimator method over 2002-2011 period.‌‌ Among the various interpolation methods including Kriging and inverse distance weighting (IDW) with power 1-3, Kriging method was determined as the best interpolation method based on RMSE criterion. Results showed that spatial zoning maps of groundwater level in this period indicates intense depletion of groundwater level in the northwest of the region. Results also show that the average level of groundwater in the whole plain has decreased 3.5 m because of decreased rainfall and over-pumping of groundwater for agricultural uses in the period.

The ancient area of Rey on the central plateau of Iran is a valuable site for archeological sequences in a natural plain. It has valuable natural resources, and history and archeology specialists along with the native and non-native tourists, has given attention to this site. The archeological -natural environment of the fire temple of Rey or the archeological Tappeh Mil of Varamin, located 12 kilometers southeast of Rey, on a high hill beside the historical Ghal’e No Village, is one of the natural- archeological sites of the region. In this research, through specialized processing of ETM and Quickbird satellite data, in large and small scale and in different study layers, the ecologic structure, landscape features of the determined study region, was studied and the most prominent features of the given natural- archeological structure and the relations and interactions among them were specified in the framework of cultural landscape. Also, keeping in consideration the dynamic ecological structure and the aesthetical features of this area with its environment in integrated conservation approach, the buffer zone of the cultural landscape and the preservative precincts of the natural- archeological environment of Tappeh Mil have been determined. Based on the above-mentioned studies and the features of the landscape, environmental planning and design strategies of the Tappeh Mil have been determined.

One of the methods for water resources development to meet water supply requirements, is the use of treated urban wastewater. In this paper, the feasibility of use of refined urban wastewater of Sabzevar was evaluated. This study was implemented in Dorok desert land located in southwest of Sabzevar over three year(2009- 2011). In order to meet this general objective, the complete randomized block design with three treatments (Haloxylon, Atriplex and Nitraria schober) in 9 replicates per treatment was selected. To evaluate the quality of the effluent, the samples were taken from sewage wastewater treatment plant of Sabzevar and entering water to the collecting reservoir. The samples were analyzed in the laboratory to study the major contaminants based on environmental standards for sewage in Iran. The results of this part of study showed that all evaluated parameters are suitable for irrigation, except for two parameters of Dissolve Oxygen (it was solved by mixing it with seasonal flooding) and coliforms count in the effluent. The results in terms of classifying the quality of wastewater for agriculture and irrigation by Wilcox diagram, showed the class C3-S1, which means relatively suitable class. To evaluate the second objective, areas planted were divided into three sections and each section is divided into three parts (9 repetitions). For evaluation of plant density (percentage of plant), 120m transects was used and the results showed that on average, 67 percent of Haloxylon, 74.3 percent of Atriplex and 90.3% of Nitraria schober have survived. The results are indicators of match effects which are at 1% level meaningful.

One of the striking aspects in the world is the phenomena of desertification and degradation of natural resources and international efforts has been considered over the last decades to combat and prevent this phenomenon. The most important cases of these measures are the United Nations Convention to Combat Desertification and adaptation to drought effects. The Convention introduced some measures on desertification monitoring and assessment to the member countries. The aim of this study was to assess desertification model IMDPA is Yazd-Ardakan plain. During this study due to time constraints and literature, some indicators of water and climate were selected for each condition of the region. Indicators to measure were groundwater levels depletion and electrical conductivity for water criterion; and drought, aridity and continuous droughts period for the climate criterion. First, the geometric mean of indicators and the criteria of desertification was calculated and based on the quantitative indicators and benchmarks desertification status was classified in 5 classes including non-significant, low, moderate, severe and very severe, and desertification condition map were drawn using GIS in the studied period. According to the results and the numerical measured values, groundwater level depletion with the value of 3.84 is the most effective indicator while continuous drought period with the numerical value of 0.53 showed to have the lowest impact on desertification of the region. According to the analysis, the numerical value of the water criterion is 3.44 is the most effective factor which shows severe condition of desertification in the region.

Land cover and land use change occurs during the time due to human activities. Identification and detection of these changes can help planners and managers to recognize the effective factors which cause the changes, and use them at different levels of planning. Studying the rate of resources changes and destruction, and prediction and feasibility study of these changes in future years may play a key role in planning and optimal use of resources and controlling undesirable changes in the future. There are various methods for predicting land use and land cover changes, among them the Markov Chain model can be pointed out. In this study, by using the Landsat satellite data of TM (1995) and ETM+ (2000 and 2007) sensors, complementary data of the study area and Markov Chain model the changes occurred in land use and land cover over the past 22 years in Doviraj region of Ilam province are investigated. After performing required corrections on the satellite images and field visits, different land use classes were defined, the training samples were selected and the accuracy of obtained results was evaluated using Kappa coefficient. The results indicate the decreasing trend of forest cover and average rangeland areas of the region (i.e. 2.9 and 17.07 percent, respectively) and increasing trend of poor rangelands, agricultural lands, residential areas and barren land uses (9.17, 2.96, 0.4 and 7.44 percent, correspondingly) which represent total destruction in the region and replacement of weaker land uses. Finally, using Markov Chain model, the status of land use classes in the next 14 years (2021) has been predicted. The results from changes prediction matrix based on the maps of 2000 and 2007 showed that in the time period of 2007-2021 it is probable that 62% of forest lands, 38% of average rangelands, 64% of poor rangelands, 72% of agricultural lands, 69% of residential areas and 76% of barren lands remain unchanged. The average rangelands are of the highest stability and on the other hand poor rangelands have the lowest stability. The calibrated land use maps by Markov Chain model can be employed as an alarming system about the effects and consequences of future land use changes.

Numerous indicators for drought monitoring in different time scales have been used for monthly and yearly data series. One of the limitations of conventional indicators such as the Standardized Precipitation Index (SPI) is no attention to the water balance based on the amount of evapotranspiration. The Standardized Precipitation Evapotranspiration Index (SPEI) which is based on precipitation and potential evapotranspiration incorporates the water balance in the drought index.The purpose of this study isinvestigating the intensity, duration and frequency of the meteorological droughts in Tehran province using SPI and SPEI in order to determine the relationship between these indices for optimized management of water resources. In this study, the data of monthly precipitation and average monthly temperature for a period of 30 years (1978-2008) in six gauging stations in Tehran province were used. The results indicated that there is a significant correlation between SPI and SPEI while SPEI show a quick response to the meteorological drought.