فهرست مطالب ناصر باغستانی

The loss of vegetation and the prevalence of decay in Artemisia habitats due to climate change and management factors necessitate the need to focus on a conservation approach in the management of these ecosystems. In this regard, the effect of the conservation approach (exclosure with a history of 30 years) on the structural components of vegetation, soil characteristics, and values of numerical indicators of species diversity in the Artemisia habitats of the Dehno-Bardsir region was investigated. For this purpose, vegetation sampling was performed during the growing season of 2013 inside 45 two-square-meter plots located along three transects of 150 meters, inside and outside the enclosed area. Within each plot, the percentage of canopy cover of species was estimated and the number of their bases was counted based on the percentage of canopy cover of species, indices of species diversity were calculated. Along each of the transects, a composite soil sample was taken from a depth of 0-30, and their physical and chemical properties were measured. Based on the results, in terms of canopy cover percentage, only in the case of Stipa arabica, there was a significant difference between enclosed and non-enclosed areas. In terms of the number of bases per hectare, there was only a significant difference between Zygophyllum atriplicoides and Stipa arabica, and in terms of presence only between Artemisia sieberi, Stipa arabica, and Zygophyllum atriplicoides, there was a significant difference inside and outside the enclosure. In sum, the exclosure will cause Stipa arabica to dominate the area. There was no significant difference between soil properties (percentage of clay, silt, and sand, electrical conductivity, acidity of saturated mud, amount of lime, calcium, magnesium, and sodium) in the two places. The amount of species richness in the enclosure area (with 21 species) was higher than in the grazing area (with 16 species). The values of Simpson and Shannon-Weiner indices also indicate no difference between the two places for evenness and heterogeneity of vegetation. What is certain is that the results of three decades of exclosure showed that the process of vegetation change in the valleys of arid regions is slow. Applying a conservation approach in such ecosystems will be effective in the long run.

    This study was carried out in the Serizi- Bafq flood water spreading area of Yazd province. Vegetation sampling was performed in four flood spreading areas and the adjoining area as control in a completely randomized design. In order to investigate the vegetation changes, the transect-quadratic method was used and three transects with a length of 100 meters were established. On each transect, 10 plots of 5×5(m2) were used. Collectively, 120 plots were installed inside the flood spreading area as well as in the control area. The parameters of canopy cover, density and presence of the plants in the flood and control areas were measured. The data were analyzed using t-test in SPSS software. The results showed that the percentage of canopy cover, density and presence of Hammada salicornia, Seidlitzia rosmarinus as well as the percentage of total canopy, total density and total species presence showed a significant difference at the 1% level. A significant difference was also found for litter coverage at the 5% level. The total percentage of annuals, Zygophyllum europterum, Salsola yazdiana, and Artemisia seiberi in the flood and control areas was not statistically significant. Flood water spreading operations have led to the presence of Zygophyllum europterum, Salsola yazdiana, and Artemisia seiberi. The vegetation percentage of these species is low in the current situation, but with repeated water logging in the flood spreading area, there may be significant changes in the long-term vegetation composition.

Based on the importance of runoff harvesting method in arid lands, effect of these systems on vegetation production and cover and soil moisture was evaluated. Soil and vegetation were sampled in three sampling areas (Control, Curved pits, Catchment ponds) using randomly-systematic method and in each site (50 hectares), 98 plots were sampled with intervals of 70 m within plots of 1*2 m and in total, 294 plots were used. Yearly growth of the vegetation was cut within 25% of the total plots (294) and was dried and its weight was considered as vegetation production. Twenty percent of total plots related to vegetation cover in each site were selected and two soil samples were sampled in each plot to evaluate soil moisture variation in two depths. The results revealed that the cover percentage as well as vegetation production increased at about 2 times in catchment ponds site and 1.5 times in curved pits site in comparison to the control site. According to the results, it seems that catchment pond method has better performance in comparison to the curved pit for increasing soil moisture and vegetation production and therefore priority of these systems can be advised for rangeland improvement and reclamation in arid lands.

The adaptability of Haloxylon appilium to adverse environmental conditions and especially its capability for an appropriate establishment in saline and desert soils has introduced this plant as a suitable means for biological methods to stabilize sand dunes, control erosion and prevent desertification in arid regions. In order to evaluate the ecophysiological characteristics of Haloxylon appilium some characteristics of soils under the long term establishment, survival and development of this plant and ion composition of this plant growing in Yazd province in thirty two growing trees of similar ages and traits within 8 locations of Chah Afzal and Ashkezar were investigated and their height (H), crown diameter (CD) and the above ground biomass index (Yi) were measured. Also, after cutting the trees from their collars, soil profiles were dug underneath the tree locations and soil samples were taken at depths of 0-30, 30-60, 60-90 and 90-120cm from four sides of each profile. The samples were then analyzed for Electrical Conductivity (EC), pH and Cl, Na, Ca, Mg, K concentrations in 1:5 soil to water extracts. The results showed statistically significant differences in soil parameters between the two regions, except for pH and Mg concentrations. The ion concentration of the plants in the two regions showed statistically significant differences for only Cl in shoots and Ca in roots. Based on the plant growth indices the Chah Afzal and Eshkezar regions were respectively evaluated as suitable and unsuitable for Haloxylon appilium growth. In spite of a higher salinity, the higher Ca and K concentration and lower Na/K ratio of Chah Afzal soils may explain the better plant performance in this region against Eshkezar, however, comprehensive researches on application of Ca and K fertilizer are needed to confirm this hypothesis

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.

This research was conducted to investigate the relationships between soil (organic matter, potassium, phosphorous, sodium, fine gravel, soil texture, EC, lime, gypsum, nitrogen) and environmental (elevation, slope) factors with distribution of vegetation types in rangelands of Sabzdasht, located in Bafgh, Yazd province at 2012. For this purpose, four vegetation types were selected as follows: Artemisia sieberi; Artemisia sieberi, Stipa barbata, Eurotia ceratoides; Dorema ammoniacum, Artemisia sieberi, Eurotia ceratoides; and Hammada salicornica. Minimal area was determined using nested plots. Afterward, vegetation factors were measured and five soil profiles were dug randomly in minimal area. In each profile, data for depths of 0-10 and 10-80 cm were recorded. Principal component analysis was applied to analyze the data. Results showed that soil texture, potassium, phosphorous, EC and lime had the most impact on variation and distribution of vegetation types.

Canopy cover data are important for range management decisions and there are different methods of estimation. Introducing a method with adequate speed and precision and low cost is important in range management studies and researches. According to development of new technologies in photography soft- wares and hard-wares, it can provide an opportunity to study in a large scale at a short time and low cost. If its accuracy be fine, then it could be used in monitoring projects. This study carried out for study of accuracy and efficacy of vertical photos prepared with digital camera and application of existing soft-wares in estimations of canopy cover percentage of shrublands in Yazd province. Three sites representing Yazd shrublands were selected: 1- Nir rangelands with Artemisia aucheri as dominant species, 2- Shirkooh rangeland with Artemisia sieberi as dominant species and 3- Chahafzal rangeland with Seidlitzia rosmarinus as predominate species. Sampling was carried out in these three sites after determining sample size with drawing method and plot size according to the canopy of dominant species. Photography was performed in suitable height using a camera in the centre of plot and makes sure the photo include the whole area of plot. Simultaneously, canopy cover percent was measured directly with meter tap. Canopy cover percentage also was determined by prepared digital photos after inserting them to computer and using Arc View soft-ware. The percentage of canopy cover by species, in photography and direct methods were compared using SPSS soft-ware and using Paired T-test. There were not significant differences between canopy cover percentages estimated by two methods at %5 level. According to the results Photography with existing soft-ware could be used for determining canopy cover percentage in shrub lands of Yazd province.

Five distance sampling techniques used to estimate density for Artemisia aucheri andCornulaca monacantha species in this survey include: point center quarter, closest individual, nearest neighbor, random pairs and angle order methods. Sampling was conducted within 3 (40 m ×100 m) sampling areas selected in TangLaybid. 30 points were selected equidistant apart along 10 randomly located 100-m transects for measurement of distance within each sampling area. Density obtained by each method was compared to the total count in a randomized complete design and Duncan’s test. Hopkines and Eberhardt indices were used to detect dispersion pattern of plants. The point center quarter method provided a reliable estimate of density for Cornulaca monacantha in the community with density of 0.38/m2 and a clumped distribution. The nearest neighbor method gave a reliable estimate of density for Artemisia aucheri in the communities with density of 1.8/m2 and 2.9/m2 and a tendency toward uniformity. Results showed that the point center quarter method can give reliable results inshrub communities with cover around 10% and a clumped pattern while the nearest neighbor method can give a reliable estimate in communities with cover between 16-20% and a uniform pattern.

The present study discusses a method used to produce updated information about vegetation cover in arid and semi-arid zones, using RS data and GIS technique. In this method, Landsat ETM+ data in 2002 was collected in an area of about 60000 ha in Nodoushan basin, Yazd, Iran. To collect the necessary ground data, 50 sites of different vegetation types were selected and the percentage of vegetation cover in each one was determined. Also, different vegetation and soil indices were derived and crossed with located sampling points using ILWIS software capabilities. To get the best fitted curve, the relationship between vegetation cover, as a dependent variable, and satellite data bands, vegetation indices and environmental factors, as independent variables were assessed. Therefore, a multiple linear regression model was established for the prediction of vegetation cover percentage in the studied area. Finally, a vegetation cover map with high a precision was produced. As a conclusion, it can be said that mapping of vegetation cover via remote sensing is possible even if its vegetation cover is sparse.

Remote sensing is a method to produce updated information in vast area. Describing the model for utilization and processing satellite data in regard to developing a method for mapping forage production of arid regions were the purpose for this study. For this purpose Landsat ETM+ data used at Nodushan area in 2002. The study area covers about 60000 hectares and the annual precipitation is about 140-300 mm. in order to correct the necessary data 50 sites with different vegetation types using 25 quadrant of 1*2 m size and then awareged were used. To study the dependent variable of vegetation relations with independent variables of satellite data, vegetation indices and environmental factors; multiple linear regression analysis were manipulated using SPSS software. Then a suitable model was selected which caried predict the vegetation properties of the study area. Finally, production map was produced using ILWIS software. According to the results, mapping of forage production via remote sensing is possible even when its vegetation cover is less than 25%.

An optimal planning system for managing the range and maintaining it’s vegetation is highly influenced by the humidity and rainfall of the range. In this research, the reactions of the seidlitzia rosmarinous species to the fluctuation of precipitation and under ground water were studied at Chah-Afzal in Ardakan-Yazd. Regarding the amount of collecting data after five years, by applying Minitab software, using linear regression, an equation between the amount of the production and precipitation was obtained with a high correlation coefficient (r=0.93). The results showed that the variation of the plant production was due to the fluctuation of the annual precipitation. Moreover, result of another analysis was demonstrated a lack of agreement between the cover and density of the se.rosmarinous species with the amount of precipitation. In addition, the results state that the downward trend in the percentage of canopy cover and the density of the se.rosmarinous species in the region are highly influenced (r=0.94 and r=0.99 respectively) by the discharge of ground water table. Thus, the gradual decrease of this source in the coming years might bring out negative effects on the cover, density and finally on the condition of the range in Chah-Afzal. Also, Interaction between the effect of ground water table changes on the amount of forage production was not significant.