NATURAL ECOSYSTEMS OF IRAN
Year:2011 | Volume:1 | Issue:3|Papers Count:9

Drought is one of the greatest natural disasters that have more effect on human societies than the other natural disasters. Monitoring systems are very important to management and providing drought fighting plans and therefore we use quantitative index to explain this phenomenon. These indices are calculated in the points, so we have to process them spatially by the means of interpolation methods such as geostatistic. In this research, capability of Kriging, Cokriging and Inverse Distance Weighting (IDW) to spatial analysis of climatic drought in three coastal providence of Caspian Sea were processed. The drought analysis was done by use of 30 year dataset belonging to meteorological gauge stations and then climatic drought maps were provided and assessed. The variographic analysis confirmed that the SPI index is a spatial index meanwhile showed that the Kriging method has more accuracy in drought zoning than the other methods. Examination of correlation among samples based on attributing spatial variance (C) to (C+C0) which is more than the 0.5 showed that SPI index has moderate to strong spatial structure. It shows that the climatic drought has spatial correlation in this region. In this area, the spatial correlation of meteorological gauged stations has been effective until 800 km.

Accurate identification of resources and proper planning are the most critical factors for management of natural resources. In this study, in order to fulfill proper planning, I compared 3 approaches namely: GIS, rangeland management plans and indigenous knowledge of rangeland exploiters in order to identify best sites for rangeland improvement and development projects in Jashloobar rangeland in Mahdishahr Township– Semnan Province.At the end, the degree of accordance among these three methods was determined and the best approach for proper management of rangelands was offered. In this connection, different layers of information such as slope, altitude, soil, vegetation, rangeland condition and trend, etc were laid in GIS and finally, by integrating principal guidelines into rangeland management plans, final maps were produced. I also studied the maps demarcating the sites of rangeland improvement and development projects of different pastoral units. After desk studies, I visited the pastoral units and filled the questionnaire about rangeland and exploiter with the exploiters of each pastoral unit. Eventually, it indicated that the formulated projects for pastoral units (rangeland management plans) did not comply with the potentials of rangelands and more attention should be paid during developing of rangeland management plans. It also suggested that some of the projects should be reviewed. I also noticed that exploiter's view somewhat differs from the potentials of rangeland or they express their views favoring some special objectives. Thus, they should have some training in this regards. The results imply that application of GIS associated with accurate data from rangeland can help experts in identification of proper and efficient rangeland development and improvement projects and thus speed up the rehabilitation process.

One of the most important factors which influences high productivity and regeneration of annual medics on the improvement of dry lands and rangelands is the cultivation deep and seed size of annual medics. Nowadays the plant fertilizers can improve dry lands and rangeland by reducing soil erosion and fertilizing the soil as well as the forage production. As plant fertilizers, annual medics have high correlation between their cultivation deep, regeneration, seed size and their growth. So the determination of cultivation deep and seed size are regarded as a main factors for success of improving programs in dry lands and rangeland in a certain region. Chosen for experiment are six species of annual medic which can survive in different climates, produce sufficient forage, and fertilize the soil effectively.The experimental design in two sections: one was a 6×3×3 factorial employing Randomized Complete Block (RCB) with tree replications within 65 days. Tree levels of deep of cultivation chosen for species under study as 1cm, 2cm and 3cm. (factor A: species, factor B: deep). Other section was a 6×3×2 factorial employing (RCB). Two levels of size was big and small size (factor A: species, factor B: size of seed). The results showed that there is no significant difference in the diverse species in tree level of deeps, but there is most plant in 1cm deep of cultivation. Also there is significant difference among diverse size of seeds in the weight of dried forage, height and nodules in species. In big seeds weight of dried forage in all species averagely is 4098.5 kg/Hec. While mean weight of dried forage in small seeds is 3280.17 kg/Hec. Height of plant in big seeds and small seeds was 27.79 and 21.08cm respectively. Big seeds produced most nodules which in big seeds was 12.92 and in small seeds 11.83nodules.

For consideration the effect of plantation on soil physical and chemical characteristics, a planted area with almond with an area of 50ha was selected in Dezfool area. A 10 ha without plantation area was selected as control area. Nine soil samples were selected per area in three depths and were tested in soil laboratory. Five sample plots with an area of 20*20 m2 were selected systematic randomly per zone for plants cover and biodiversity.30 micro plots including 3 micro plots in per sample plot for herbal species.For data analysis, the Kolmogorov-Smirnov normality test was used to test the normality and Levens' test was used to determine homogeneity of variances. Then due to normal distribution of data improved by Kolmogorov-Smirnov normality test and equability of variances showed by Levens' test, one way analyses of variance (ANOVA) were used to general comparison of more than two groups and independent samples T test for comparison of two groups. Duncan’s multiple range tests was used to separate the means of dependent variables which were significantly affected by independent. The results showed significant effect of plantation and its herbal cover on some soil characteristics.

Use of native cool - season grasses are important due to adaptability, soil conservation, livestock grazing, and forage production in rangelands. However, Emergence and seedling establishment are critical phases in rangeland management particularly in arid and semiarid regions. The objective of this study was to evaluate the impact factors on emergence and seedling establishment characteristics of seven cool - season grasses (Agropyron elongatum, Agropyron pecteniforme, Bromus inermis, Bromus tomentellus, Festuca ovina, Dactylis glomerata, Secale montanum) in field conditions on sites in northern khorasan in 2005.Field experiment was using randomized complete block design with four replicates. The emergence percentage, emergence rate and status of seedling establishment by measurement of seedling various components at the end of experiment were studied. Analysis of variance revealed that no meaningful difference between species for final emergence occurred but species had significant effect on emergence rate and different characters of seedling growing (p<0.05).The most emergence percentage on all studied regions, were related to the large-seeded grasses such as: Secale montaum, (about %23.5). These results suggest that seed size and tiller seedling and speed of species emergence could be effective on grasses establishment.

Environment stresses, e.g. extremes of temperature and light and water availability can reduce the ability of a plant to metabolise. This can mean an imbalance between the absorption of light energy by chlorophyll and the use of the absorbed energy in photosynthesis. In this research we have examined the effect light high stress and water deficit separately and simultaneously together, in wheat seedling. For high irradiance stress treatment, grown seedling was exposed to 250wm-2 for 2h daily for the next 5 days. For water stress treatment, instead of distilled water, 5% queues polyethylene glycol-4000 solution was added to control irradiance seedling. For high irradiance stress and water stress treatment together, seedling irrigated to poly ethylene golycon instead of distilled water and exposed to 250wm-2 for 2h daily. Results were observed that in HIS+WS together treatment chlorophyll and caroteniod pigments rate was showed the most decrease. More decrease in excition energy transfer was observed both in PSII and PSI of stress treated samples in HIS+WS together. Photosynthetic activity or photo reduction of DCPIP by chloroplasts also in HIS+WS treatment was the most compared to control and other treatments. Fluorescence intensity also was showed highest decrease in HIS+WS treatment compared to HIS stress and WS and control.

The afforestation efforts is one of the methods used for ruined land restoration and renovation in the north forests of the country and for this reason the evaluation of each planted species especially local species has a special and great importance. In this study Alnus subcordata, Acer velutinum, Fraxinus excelsior species from the view point of qualitative and quantitative attributes were studied in Guilan’s Toutki forests. The inventory was done by systematic-random method in 57, 5R Sample pieces (500 m2) and with an intensity of 5 percent. The results obtained from this study showed that the diameter and hight mean a also the annual hight growth and the Alnus subcordata volume mean are in order 40 cm, 23 m, 0.75 m, 45.58 silve and compared to Acer velutinum and Fraxinus excelsior are greater amounts. From the view point of tree distribution in different diameter levels it was distinguished that Acer velutinum and Fraxinus excelsior have normal distribution but Alnus subcordata lacks this attributes. From the view point of studied qualitative attributes except the trunk twist attribute there is a significant difference at the level of a=1% among the three species. From this view point afforestation with Alnus subcordata species regarding the qualitative and quantitative variables has the best condition and regarded to Acer velutinum and Fraxinus excelsior the have more developing capability.

For investigation on seed dispersal and sexual regeneration natural establishment of Quercus brantii, Pistacia atlantica and Acer monspessulanum, area about 700 ha of Meantang forests located in north of Ilam has been selected. Then forest inventory was done with random- systematic sampling method by choosing 20r plots to record forest stands and 4r plots to record regeneration. Variables in macro-plot were included stem height, max & min diameter for all trees. Also number of seedling was counted in each micro-plot. Results showed that seed dispersal distance was differenced in relation to species kind, size and weight of seeds and slope. So that seed dispersal extent (SDE) of Quercus brantiiis lower than Pistacia atlantica and SDE of Pistacia atlantica is lower than Acer monspessulanum. Also seed dispersal effected in regeneration establishment of tree species. So that the highest rates of regeneration establishment of Quercus brantii, Pistacia atlantica and Acer monspessulanum have been subsequently observed under shade and shelter of trees and bush and shrubs and the lowest rates were happened in open areas. Also frequency of regeneration was most in the north aspect and north side of trees.

This research investigates the most important environmental factors of Artemisia genus distribution in relation to edaphical and physiographical factors in Fars steppic rangelands. So 27295.4 ha of rangelands Abadeh has been selected and in elevational gradient through 1900– 2400 m. density and abundance of Artemisia genus in 268 quadrats 1m2 along 4 transects of 300m and 8 transects of 100m. width. Soil profiles has been estimated out of final landform maps in ArcGIS and Sorenson index which estimated 106 soil profiles through the studied region. Physical and chemical parameters such as texture, organic carbin, K, P, N, pH, EC, Caso4, Caco3, Slope, Aspect and elevation has been analysied by DCA and CCA. Results showed Artemisia sieberi is dominant species through 1900-2200 which has the strong relation with parameters such as P, pH, %sand, elevation as primary factors and K, Caso4, Caco3 as secondary ones and Artemisia aucheri is dominant species through 2200-2400 m. that elevation and %sand as primary factors and K, %clay and slope considered as secondary on has the most important in Artemisa geus distribution. It is important to mention that far away of land and closing to mountain the precipitation will be increased because of orographic effects results from topographical changes.