Journal of Rangeland
Year:2008 | Volume:1 | Issue:4|Papers Count:10

Fire effects on vegetation and range improvement are different in various climatic condition and burning times. In this research, fire effects were studied on plant species in steppe rangelands of Yazd. For this aim, I hectare restricted area was selected in Nir range research station. A randomized complete blocks design with 5 treatments (burning in spring, summer, autumn, winter and control) and 4 replications were carried out in 2004. The first measurement of species yield was conducted in late September 2005.Similar measurements were done in 2006. The results showed that amount of yield of salsola rigida in winter treatment were the least of negative effects between the other burning treatments and its yield with control treatment was not significantly different.Burning, destroyed the indicator plants of Artemisia sieberi, Stipa barbata and two undesirable plants; Noaea mucronata and Cousinia deserti. After two years, yield of Scariola orientalis (undesirable plant) significantly increased in burning treatments in comparison with control treatment (p<0.05), andno decrease was observed in Launaea acanthodes. Although, yield production didn't decrease in winter treatment, but I and II classes plants yield decreased while III class plants yield increased. Totally, the results of this study showed that the qualilative yield of the steppic rangeland will not increased by burning.

The current research was carried out to compare modeling methods for providing their predictive habitat models. For this purpose, study was conducted in Poshtkouh rangelands of Yazd province. For modeling, vegetation data in addition to site condition information including topography, climate, geology, soil and grazing intensity were prepared. Sampling was done in homogeneous units, which these units resulted from overlaying of hypsometry, aspect, slope, geology and vegetation maps. Within each unit 3-5 parallel transects with 300-500m length, each containing 30-50 quadrates (according to vegetation variations) were established.Sampling method was randomized-systematic. Quadrate size was determined for each vegetation type using the minimal area; hence suitable quadrate size for different species ranged from 1*2m to 10*10m (2-100 m2). Soli samples were taken from 0-30 and 30-80 cm in starting and ending points of each transect. Measured soil properties included gravel, texture, available moisture, saturation moisture, organic, matter, lime, gypsum, pH, electrical conductivity and soluble ions (Na+, K+, Mi+, Ca2+, cr, CO2-3, HCO-3) and So2-4). CCA and Logistic Regression (LR) techniques were implemented for plant species predictive modeling. To plants predictive mapping, it is necessary to prepare the maps of all affective factors of models. To mapping soil characteristics, geoestatistical method including variogram analysis and Kriging interpolation were used. Based on obtained predictive models for each species (through LR method) and for whole species (through CCA method) related predictive maps were prepared in GIS. The accuracy of predictive maps were tested with actual vegetation maps. Vegetation modeling results with CCA indicates that predictive map of vegetation corresponds with actual map (with high accuracy). Predictive maps of species, which have narrow amplitude, is as the same of actual vegetation map prepared for the study area. In general, LR will provide better specific-model, but CCA will provide a broader overview of multiple species.

In order to determine apicultural potential in Polour summer rangelands, an area about 4600 ha specified on the topographic map (scale: 1/50000). Regular visitation had done in commencement of rangeland plants.Composition percentage of all plants was determined by laying out 26 plots. Favourable honey bee plants recognized by direct observation method. Attractivity index determined by combining two factors of number and time of standing of honey bees on plants in 5 minutes and on fix area (100 cm2) in investigated area. Finally, by multiplying the attractivity score of each plant by cover percentage the score of plants in the site was computed. According to the total score of each site, the favourable honey bee plants were classified as excellent, good, fair and poor in the view of apicultural calendar.

Converting range lands to farm lands is one of the most important factors in range land degradation. The aims of this study were to investigate the effects of this changing on composition and diversity of plant species in Tangab dam sub' basin rang lands in Firouzabad, Fars province. Vegetative characteristics, included species presence and cover percentage, were investigated at two cultivated areas; long and short term cultivation areas in two types of vegetation; scrub and shrub land. Cover percentage of species was recorded in three cases; individually for each species, grouping (based on life forms, growth form and families) and total species. Results showed that some species occured in both cultivated and range land, whereas, some of them were specific for cultivated or range land. Cover Percentage of Boisseiera squarosa and Gunde/ia tournefortiiat scrub, and those of Scarolia Orientalis at shrub land areas showed a significant decrease in cultivated areas comparing with types of range lands. On the other hand, species of Carthamus oxyacantha and Scaro/ia orienta/is at scrub and species of Turgenia latifolia, Achillea wilhelmsii and Silene arabica at shrub land had significantly higher canopy at arable land. In both types, cover percentage of life span (annuals, perennials), life forms (forbs, shrubs and trees) in some important families (Leguminosae and Compositae) decreased, while it increased significantly some Leguminosae and Umbelliferae species at cultivated areas contiguous to the shrub lands. Richness and diversity of species showed significant decrease in cultivated lands related to range land. Multivariate analysis showed that scrub, shrub land and cultivated lands were completely seperated in view point of vegetation. Result of this investigation showed that development of cultivating operations on range land ecosystems could be lead to plant composition changes and diminish the species diversity.

One of the practical solutions for soil conservation, could be rain-fed pasture species cultivation. Studying the cultivated rain-fed Onobrychis viciaefolia areas confirmed that appearing of Scariola orientalis and Agropyron elongatum cause its population reduction. It seems that the reason is allelopathic effect of these two native species. To study of these allelopathic effects, two various experiments were carried out on O. viciaefolia seeds. The first experiment was designed with 3 seed treatments (seed, seed with pod and seed with broken pod), 5 extracts with 4 replicates. The extractions were extract from a) and b) whole parts of the S. orientalis and A. elongatum, c) leaves , d) roots & e) stems of S. orientalis.The second experiment was designed with 14 treatments: 5 treatments were extracts from two native species, 3 treatments of extraction methods and distilled water as control. The plant material extracts were the same as first experiment and the extraction methods were using three different solvents of hexane, dichloromethane & methanol. Seed germination, germination rate and germination speed of 0.viciaefolia seeds under irrigation of various extracts were recorded in both experiments. According to the analysis of variance, the extracts of the two native species significantly decrease the seed germination, germination rate and germination speed of O.viciaefolia. In the second experiment the treated seeds with A.elongatum extracts germinated only 4.7% while the control was 78% which there is an eighteen times germination reduction. This is due to allelopatic effect of both native pasture species which are belonging to the main pasture communities before ploughing to cultivate.

Legume plants, due to their distinctive eco physiological characteristics, could endure environmental stresses, and do have important roles in sustainable pastures production, recreation and improvement. Leaf movement of legume plants is turgor regulated, and osmotic cally active fluxes of ions between extensor and flexor of pulvinus cause this movement. To determine the role of calcium ions in circadian leaf movements of bush bean plants (Phaseolus vulgaris L. cv.Provider), a radiotracer technique experiment using 45Ca ions were employed.Measurements were taken during circadian leaf movements, and samples were taken from different parts of the leaf. The 45Ca activity reduced from leaf base pulvinus to leaf tip. The pulvinus had the highest activity, while the leaf tip had the lowest. The ratio of 45Caactivity inside extensor to that of flexor (Ex/Fl) increased, while the midrib-petiole angle, as an indicator of leaf movement, decreased with time. The relationship between 45Ca activity inside extensor and that of flexor was highly significant (r=0.97, p<0.001).The relation between midrib-petiole angle and Ex/Fl 45Ca activity ratio was found also significant (r=0.65, P<0.05). In conclusion, it was found that calcitim ions accumulation is opposite to the fluxes of osmotic ally active ions and water movement. Calcium ions accumulate at less negative water potential side of the pulvinus.

Rangelands of Iran are one of the valuable natural resources to attain important goals such as livestock's nourishment and feeding, soil erosion control, flood control, recharging of water subterraneous surfaces and also wild animals' protection. Attention to these goals and implement these projects, based on their financial evaluation, will help to attain aforesaid aims, influentially. Therefore, in this research, one of the rangeland management projects of Mazandaran province was analyzed with this purpose that explains its financial evaluation. Results show that this project has financial evaluation by using of present value, benefit to cost ratio and internal return rate methods and internal return ratio is 23. 34 percent. Also, the results of different interest rates, incomes, costs and the project implementation years were analyzed by sensitivity analysis. The results of sensitivity analysis imply that the project will have financial return when interest rates are less than 23 percent and the internal return rate will be positive and equal to 12.31 percent when incomes change until 14 percent of previous income of the project implementation. Also, the project will have suitable return when costs increase 5 and 10 percent and internal return rate of the project will be 5.24 percent when costs increase 12 percent. In addition to, internal return rate will be 40 percent when project implementation years change until 15years and after that it will be constant, nearly. Finally, political comments have been propounded to implement these projects, suitably.

Renewable natural resources degradation as a main problem, has attracted the thought and force of experts and natural resources responsibles during the last decades.Some effective factors in this category are legal (laws deficiency), organization and official legislations of natural resources organization. Aim of this research was to clear this factors. For his purpose, 11 provinces located in various climatic regions of country, were selected. Data collection was performed using a questionnaire including 7 questions about natural resources.The related expert’s opinion about legal affairs and official problems that contributed in renewable natural resources degradation was considered in the questionnaire. From total 876 sent questionnaire to the understudy provinces, 504 were received and analyzed. Results showed that no sufficient staffs and equipment’s (21.2%), no satisfaction and low motivation of personal (16.4%), no sharp legislation (16.2%), and other factors like no clarification legal and courts are effective in natural resources degradation. Management methods, are also effective in natural resources degradation. Government management is responsible for 22.8% of degradation. On the other hand, common utilization caused 17.9% of degradation and group management in range management projects due to their public management lead to 15.6% of degradation. Delivering the public lands to no indigenous peoples for some industrial projects leads to 12.1% of natural resources degradation. Rangelands cooperation management method as another method is responsible for 14.8% of degradation. Private management of natural resources by a family is the best method because it has the less effect on natural resources degradation. Due to socila groups different utilization methods, the resulted percentages in view point of their effect on natural resources degradation were as villagers 47.4%, nomads 32.3% and urbanites 20.3%. are effective in natural resources degradation.