نشریه خشک بوم
سال چهارم شماره 2 (پاییز و زمستان 1393)

This study was focused on food composition and preferences of Chinkara (Gazella bennettiishikarii) in Darreh Anjir Wildlife Refuge (DAWR) in spring season. We determined distribution of Chinkara in the region. A total of 12 transect lines were selected in the area and were surveyed on foot. We identified plant species which had eaten by Chinkara along transects. Since there is no similar herbivore in DAWR، the possibility of recording plant species consumed by Chinkara was provided through pursuing footstep and surveying the effect of animal teeth on bushes. Cafeteria experiment was used to determine the food preferences of Chinkara. Results of the study showed، food composition of Chinkara in growing season (spring) mainly consisted of 24 plant species، belonging to 21 genera and 11 families. The results of cafeteria experiments showed that preference values of the plant species for Chinkara were significantly different in growing season. Based on this study، Chinkaras were an intermediate feeder in spring season، and the herb components were the main part of their diet in this season. Annual plants، Zygophyllum eurypterum، Fortuynia bungei، and Haloxylon aphyllum were the main preferred species for Chinkara in spring season.

General circulation models (GCMS) are only tools to predict future climate condition under climate change scenarios. An outstanding issue with the use of GCM output for regional and local application is the coarse spatial resolution. So there are various methods to predict، climate variables at regional، local and a station scale that all these methods are known downscaling. The Statistical Downscaling Model (SDSM) is one of the most used methods that identifies relationships between variable predictors (output GCM) and variable predictands (Temperature، precipitation، etc. in particular station) using multiple linear regression. Intergovernmental Panel on Climate Change (IPCC) has determined two periods (1961-1990) and (1971-2000) as baseline to compare the effects of climate change in future periods. As well as reanalysis data، that produced by the National Center for Environmental Prediction (NCEP) are important components for the structuring of the SDSM as they supply the predictor values for thecalibration and validation of the model. Type and period of reanalysis data can be effective in model accuracy. In this study for downscaling temperature and precipitation variables the sensitivity of the SDSM model was examined to type and reanalysis dada of NCEP in Kerman meteorological station. The mean absolute error (MAE) was used to determine the sensitivity of the model. Result showed that the model is sensitivity to both type and base period reanalysis data. The mean absolute error of the reanalysis CGCM model data، for the average maximum، minimum and mean temperature variables equal to 11، 4. 5 and 4. 7 times the case that theHadCM3 model data is used respectively. In the case of the base period، when data of (1961-1990) is used، MAE for the mentioned variables and daily precipitation equal to 3. 5، 1. 4، 3. 5 and 1. 4 times that the state which is used for the base period (2000-1970)، respectively.

The present study aimed to investigate rate of photosynthetic recovery Calotropis procera seedling under drought stress at greenhouse conditions were conducted. This research was at two separate experiments، first experiments، 6 level periodic drought stress (3، 6، 9، 12، 15 and 18 days of irrigation interval) to 180 days and then second experiment، full recovery seedlings after the first experiment for 36 days in a completely randomized design with three replications. Gas exchange values of seedling under drought stress and recovery were significantly influenced. Drought stress and recovery experiments with increasing values of gas exchange parameters except for the water use efficiency and leaf temperature decreased. Paired T Test، values of water potential seedlings، mesophyll conductance، and intracellular concentration of Co2 and water use efficiency show of the recovery in drought levels. In general photosynthesis، stomatal conductance، transpiration and leaf temperature at the drought levels more than 3 days irrigation approximately in some of drought levels، demonstrated seedling recovery.

Traditional soil maps generally consist of some polygon units delineated on the basis of soil variation uniformity. Regarding the difficulties of this kind of maps، researchers have recently tried to use digital soil mapping (DSM) techniques in order to present spatial distribution of soil properties with less cost and time. In this research، five DSM techniques were applied to predict soil classes in the Yazd-Ardakan plain. Firstly، the USDA soil classification of 422 soil profiles across the Yazd Province were determined and coded. Then، geomorphometric parameters were related to soil data. Results showed that elevation، MrVBF، and wetness index have the most influence on prediction of soil classes up to great group level. Moreover، results indicated that decision tree، genetic algorithm، logistic regression، artificial neural network and discriminant analysis predict soil classes with overall accuracy of 60. 5%، 49%، 40%، 37% and 31%، respectively. Results also confirmed the capability of decision tree. Later technique could increase the accuracy of prediction up to 48% compared to the discriminant analysis technique. Therefore، using of decision tree model with geomorphometric parameters for soil mapping and updating soil maps is suggested in future studies.

Effect of salinity stress on the morphological behaviors of Caucasian Hackberry (Celtis caucasica Willd) seedlings، was evaluated in a completely randomized design with 20 replicates during the summer (dry part of the growth season) in this research. The experiment was carried out in Torogh nursery، Mashad city. Without stress (tap common water in the nursery) and salt treatment (source water KavirPark-Civil of Gonabad with EC 12. 03 dS. m-1) were used every two days، each time 150 ml/day. During the summer، morphological traits including height، diameter، leaf number، leaf area and were measured at the end course of growing، fresh and dry weight of roots، stem and leaf and ratios of leaf area، specific leaf area and leaf weight were calculated. Results indicated that height growth، number of leaves، leaf area at the end of growth period and leaf area growth were significantly different at 5% level and diameter growth reduced significantly at 1% in comparison with control treatment. Results of repeated measures analysis show that in salt treatment with effect of the time in all the period of measurement terms of height and number of leaves at 5% level and diameter at 1% level are significantly different، but the number of leaves did not show significant differences. The result indicated that effect of time salinity interaction for diameter was not significant but for height at the 1% level and leaf area had significant difference at 5% level.

Seed priming is a method which is potentially able to promote rapid and more uniform seed germination and plant growth. This research was carried out to evaluate the effects of priming with sodium chloride solution on germination characteristics and element concentration of Cumin (Cuminumcyminum L.) under drought and salinity stresses. Two separated experiments were implemented as a completely randomized design in a factorial arrangement with three replications. Priming treatment included (distilled water as control and two concentrations of sodium chloride solution which were 0. 5 and 1 M). For salinity stress in the first experiment، sodium chloride was used in six concentrations (0،-2،-4،-6،-8 and -10 dS/m). In second experiment، drought stress was induced by PEG solution at six levels (0 or distilled water، -2،-4،-6،-8 and -10 bar). Results showed that both salinity and drought stresses had significant negative effect on germination characters of cumin. Salinity stress significantly increased concentration of sodium. Priming had positive and significant effect on all seed germination characteristics.

To determine the effect of some important environmental factors on distribution of ecologicalvegetation groups، 50 various Land Unit Tract (LUT) were studied. In each LUT، canopy cover and vegetation density، over three line transects were measured in random plots (2 or 16 m2) according to vegetation types. For each sampling unit، one composite soil sample was collected from various depths، and topographical parameters were recorded. Soil properties included: texture، calcium carbonate، pH، EC، soluble ions (Na+، Mg2+ and Ca2+) and SAR were determined. Floristic and environmental data were analyzed by TWINSPAN and CCA methods. The CCA results showed that among the topographic variables، slope and elevation have the most effects on ecological species groups. Vegetation patterns were also significantly affected by soil variables include Na، T. N. V and soil texture.

Drought is a wide spread problem، which is seriously influencing crop production، mostly in arid and semi-arid regions. This study was conducted in two separate experiments. In field experiment، main plots were the different levels of irrigation، and the sub-plots were eight different genotypes of sesame including (Gorgan، Shiraz، Markazi، Birjand، Arzoieh، Sirjan، Ardestan and Safiabad). Results showed that different irrigation treatments have significant effect on all of the studied traits، except for the number of capsule per plant. The highest (1. 15 ton/ha) and lowest (0. 24 ton/ha) values of seed yield were observed in Arzoieh and Gorgan، respectively. Drought tolerance was evaluated at the base of field capacity (FC) (100، 80 and 50 %) in greenhouse conditions. Different traits including leaf number، shootlet length، rootlet length، dry weight and wet weight of shootlets and rootlests were measured. The highest and lowest values of dry weight were observed in Arzoieh Arzoieh (0. 015 g) and Gorgan (0. 002 g) genotypes، respectively.

Knowledge about relationship between soil and plant can help in modification and management of natural areas. For this purpose، a study was conducted to investigate the relationship between woody and herbaceous plants biodiversity with physicochemical characteristics of topsoil in forest district of Chahar-Asiab، Behbahan. Sampling was done along transects with 100 m length، 50 m away from each other. In order to investigate floristic characteristics، some plots were laid systematically along transects. Also to measure physicochemical characteristics of soil، samples were taken from different depths (0-15 and 15-75 cm) at the beginning and the end of each transect. Then، PAST and SPSS software were used to calculate biodiversity and perform correlation analysis respectively. The shannon-winer and Simpson diversity indices and Margalef and Menhinick richness indices were calculated، and correlation analysis was done between the indices and soil characteristics. Results indicated that، plant diversity in study area is correlated with some soil characteristics، so that organic matter and silt percentage had negative and electrical conductivity and sand percentage had positive correlation (p<0. 01) with biodiversity indices.