esmaeil sheida karkaj; javad motamedi; fateme alilu; hamid sirusi
Abstract
Grazing management is one of the basic elements in managing rangeland ecosystems. Proper use of grazing lands in order to achieve optimal efficiency and maintain the sustainability of rangeland ecosystems is the purpose of grazing management. In order to evaluate the response of vegetation to grazing ...
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Grazing management is one of the basic elements in managing rangeland ecosystems. Proper use of grazing lands in order to achieve optimal efficiency and maintain the sustainability of rangeland ecosystems is the purpose of grazing management. In order to evaluate the response of vegetation to grazing in summer rangelands of Chahar Bagh region of Golestan province, vegetation density, vegetation cover and functional properties were measured at five different grazing sites. Thus, using the statistics method of samples and regarding the size of the dominant plants canopy, 20 plots 1*1 meter by using a systematic- random method was considered in order to do sampling in each site and the density, and vegetation cover were recorded within each plot. Finally, parameters were analyzed using Duncan test and analysis of variance and the vegetation compositions of sites were compared using cluster analysis and Jaccard's coefficient of similarity. Results showed that the grazing intensity have significant effect on the vegetation. As grazing intensity increased, the density of desirable species decreased and density of undesirable species increased. So, the enclosure site had the highest desirable species density. Moreover, some functional types such as perennials, Hemicryptophytes, Chamephytes, grasses and decreaser plants significantly reduce with increasing grazing intensity. The greatest increase belongs to grasses with density of 9.8 and class I of palatability with density of 22.8 in enclosure site. Between functional groups, grass life form had the greatest increases in enclosure site with the cover of 19.65 percent. According to results of clustering and similarity index, pen surrounding and watering sites had similar vegetation composition. Enclosure and key area also had similar composition. In general, it can be concluded that increase in grazing intensity has caused negative changes in vegetation in study sites and the changes in watering area, village vicinity and pen area clearly observed. So, using of the management methods in order to improve vegetation indices and pushing it toward balance is recommended.
zahra zangane; Kamalaldin Naseri; Fereydoon Mellati; Mansoor Mesdaghi
Abstract
Because plant density is often measured by using plots and also in most cases are done by the method of estimation and counting the individuals, so one of the important cases that we have to decide on is the size and shape of plot. In this research, the density of Astragalus verus that it's one of the ...
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Because plant density is often measured by using plots and also in most cases are done by the method of estimation and counting the individuals, so one of the important cases that we have to decide on is the size and shape of plot. In this research, the density of Astragalus verus that it's one of the dominate species in the area and has separate and recognizable individuals plant from each other,for investigate the effects of different size and shape of plots on sampling precision and accuracy are estimated in Mayan Mashhad area. The shapes of plot are square, wide rectangular, long rectangular, and sizes of plot are 1, 2, 4, and 8 m2 respectively, that we have been investigated in total 3x4 plots (treatments). In this research, the coordinates of individual plants and the boundary of study area are located by using digital camera. Then, with help of R software, the digital map of study area was sketched. The results show that long rectangular 0.5x4 m plot has the highest accuracy and precision, so it is selected as optimum plot. Finally, it can be concluded that for saving time and expenses in sampling, using of locating coordinates method of individual plants and application of R software can be appropriate approach for estimating the density of shrublands, so for similar shrublands, the optimum plot of this research (4x0. 5 m) can be used.
Paria Kamali; Reza Erfanzadeh; Hasan Ghelichnia
Abstract
This study aimed to investigate the effect of animal grazing on soil seed bank characteristics in the northern slopes of Alborz. For this purpose, soil seed bank characteristics were compared between grazed and ungrazed areas. Therefore, four transects perpendicular to the sides of exclosure inside and ...
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This study aimed to investigate the effect of animal grazing on soil seed bank characteristics in the northern slopes of Alborz. For this purpose, soil seed bank characteristics were compared between grazed and ungrazed areas. Therefore, four transects perpendicular to the sides of exclosure inside and outside of it were established. Then soil samples were collected within 28 plots inside and 28 plots outside of exclosure along the transects from two different depth: 0-5 and 5-10 cm. Soil samples were then spread in the greenhouse and the plant species germinated in the greenhouse were identified and removed one time per 12 days. General linear model and factorial was used to study on the effect of grazing, depth and interaction between grazing and depth on soil seed bank characteristics. In case that the interactions became significant, unpaired t-test was used to compared seed bank characteristics between grazed and ungrazed in each depth, separately. In addition, paired t-test was applied to compare seed bank characteristics between two depths in grazed and ungrazed areas, separately. The results showed that all seed bank characteristics were significantly higher in ungrazed than grazed area particularly in upper layer of soil. All seed bank characteristics were also significantly higher in upper layer than the deeper layer of soil. The results implied that soil seed bank is a reliable source to recover the over grazed degraded points in the study area.
Farhad Aghajanlou; Morteza Akbarzadeh; Ahmad Mousavi
Abstract
The effect of exclosure on the changes of vegetation cover of rangelands of Ahmad-Abad region located in Zanjan province has been studied during 2002 to 2006. Three transects comprises of 60 fixed quadrate were establish within exclosure area and outside as well. The changes of vegetation cover were ...
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The effect of exclosure on the changes of vegetation cover of rangelands of Ahmad-Abad region located in Zanjan province has been studied during 2002 to 2006. Three transects comprises of 60 fixed quadrate were establish within exclosure area and outside as well. The changes of vegetation cover were studied to made comparison between the changes of manipulated factors and soil elements using t test. The results showed that total vegetation cover and vegetation cover of shrubs , perennial grasses and forbs of last year had significant difference compared to those of first year within exclosure (p
