Morteza Akbarzadeh
Volume 12, Issue 2 , September 2019, , Pages 167-188
Hamid Niknahad; Abdolbaset Aghtabye; Mousa Akbarlou
Volume 24, Issue 4 , January 2018, , Pages 708-718
Abstract
In view of the increasing adoption of rangeland exclosure in order to rangeland improvement and carbon sequestration, investigation of its effects on the soil properties and calculation of the economic value of sequestered carbon is important. The aim of this study was to evaluate ...
Read More
In view of the increasing adoption of rangeland exclosure in order to rangeland improvement and carbon sequestration, investigation of its effects on the soil properties and calculation of the economic value of sequestered carbon is important. The aim of this study was to evaluate the changes in some soil physico-chemical properties, carbon sequestration rate and its economic value following grazing exclosure as compared with open grazing areas in Bozdaghi rangelands in North - Khorasan province, Iran. Therefore, in each area (exclosure and open grazing) three transects of 500 meter length and 200 meter intervals) were set up. Along each transect, five soil samples were taken at the depth of 0–15 cm in a random – systematic method (15 soil samples in each area) and transferred to the laboratory. In the laboratory, some soil physical and chemical properties such as soil texture, bulk density, porosity, saturation percentage, pH , EC , percentage of organic matter, total nitrogen, the amount of cation exchange capacity, exchangeable sodium, potassium, calcium, and magnesium were measured and erodibility index was calculated by using the modified clay ratio relation. Data analysis was performed by using independent t test in SPSS v.16 software. The results demonstrated that establishment of exclosure in Bozdaghi rangelands had significant positive effects on soil physico-chemical properties, and reduced the soil erodability index significantly (P< 0.05). The mean value of sequestered carbon in the soil of exclosure area was significantly higher than that of open grazing area (P< 0.05) and its economic value was estimated to be 4709760 toman per hectare. According to the results, especially the high economic value of sequestered carbon in the soil of exclosure area, establishment of exclosure in the study area is recommended.
reza siahmansour; Morteza akbarzadeh; Ehsan Zandi Esfahan
Volume 24, Issue 2 , July 2017, , Pages 418-428
Abstract
This research was carried out at the Zagheh research station in Lorestan province. A number of 440 individuals in each year and 2200 individuals in five years were cut and weighted inside and outside the exclosure. The difference in weight between the individuals outside and inside the exclosure indicates ...
Read More
This research was carried out at the Zagheh research station in Lorestan province. A number of 440 individuals in each year and 2200 individuals in five years were cut and weighted inside and outside the exclosure. The difference in weight between the individuals outside and inside the exclosure indicates the amount of consumption. According to the results, there is a significant difference between the mean value of forage production and consumption in months and in different species (P<0.01). For the average of four years, the highest and lowest forage production was recorded in the third and second year, respectively. On average, forage production was calculated to be about 1,177 kg per year. On average during four years, 80% of the production was used by livestock. In all years, the highest amount of forage was produced in May. Ono.melanotricha, As. Remotijogus and As.bungei are consumed up to the basal area, while the highest consumption rate for Cen.virgata was obtained in June. Perennial grasses of the study site like Hor. bulbosum, Br.tomentellus, Festuca ovina, Stipa wiesnerii are also under severe grazing pressure. Under heavy grazing over a season, some species like Picris strigosa are not able to rejuvenate and their roots are shattered with little stress. Therefore, the imbalance between production and exploitation and inappropriate distribution is a major factor in the degradation of vegetation and rangeland ecosystems.
Zahra Jafari; Hamid Nik Nahad Gharemakher; Samira mesri
Volume 23, Issue 4 , March 2017, , Pages 680-688
Abstract
This research was aimed to study the vegetation changes under grazing and non-grazing conditions during five years in order to evaluate vegetation improvement or destruction over time.The study of vegetation changes was carried out inside and outside the exclosure within the sample units. Each sample ...
Read More
This research was aimed to study the vegetation changes under grazing and non-grazing conditions during five years in order to evaluate vegetation improvement or destruction over time.The study of vegetation changes was carried out inside and outside the exclosure within the sample units. Each sample unit consisted of two parallel transects with 20 quadrates. Within each quadrate, the canopy cover percentage and composition percentage of each species were estimated. The forage yield was measured by clipping and weighing using one-square-meter quadrates. No significant difference was recorded for the canopy cover of inside and outside the exclosure. Statistical analysis was performed in a completely randomized block design and no significant differences were found among the study years. However, significant differences were found for forage yield of inside and outside the exclosure. Therefore, the reduction in forage yield of outside the exclosure is directly related to the intensity of utilization. The life form of species was determined based on Raunkiaer's system. Hemicryptophytes was the dominant form in the study area. The results showed that although the exclosure caused to improve rangeland vegetation, the difference between inside and outside the exclosure was not significant. Generally, the results indicated that vegetation changes in the study area were slow and gradual and exclosure could not be considered as an improvement method in short-term. Direct human intervention is required for the restoration of rangelands, located in arid regions.
Amir Mirzaee Mousavand; Ehsan zandi esfahan; Farshad keyvan Behjoo
Volume 23, Issue 3 , January 2017, , Pages 606-617
Abstract
This research was aimed to investigate the effects of exclosure on species diversity changes under grazing and exclosure conditions in the northeast rangelands of Delfan County, Lorestan province. For this purpose, 120 quadrates of 1*1 m2 were established in a randomized-systematic method along 12 transects ...
Read More
This research was aimed to investigate the effects of exclosure on species diversity changes under grazing and exclosure conditions in the northeast rangelands of Delfan County, Lorestan province. For this purpose, 120 quadrates of 1*1 m2 were established in a randomized-systematic method along 12 transects of 100 m length at four altitude classes (three transects on each altitude class). In each quadrate, the list of species, density, the percentage of canopy cover, litter, stone and gravel, and bare soil were recorded. To evaluate the numerical indices of diversity, Ecological Methodology software (Ver., 6.2) was used and numerical indices of diversity and evenness were calculated. Data analysis was performed in SPSS software (Ver. 18). According to the obtained results, a number of 132 species were identified, belonging to 30 families and 104 genera, of which 124 and 108 species were recorded in the rangelands under exclosure and grazing conditions, respectively. Our results clearly showed higher numerical indices for richness, evenness, and species diversity under exclosure as compared with grazing condition. The canopy cover percentage of perennial grasses and forbs as well as litter percentage was higher inside the exclosure while the canopy cover percentage of annual grasses and shrubs as well as bare soil percentage was lower as compared with outside the exclosure. The density of perennial grasses and forbs increased, while the density of shrubs decreased inside the exclosure. In addition, a higher production was obtained from the rangeland under exclosure condition.
Mohamad Farahnak Ghazani; Mohamadreza Najibzadeh; Mohamadali Ghahramani
Volume 22, Issue 3 , November 2015, , Pages 537-545
Abstract
In recent years the utilization rate of renewable resources especially the pressure of livestock grazing has increased. Uncontrolled livestock grazing has caused reduction of quantity and quality of forage, therefore, studying the effects of exclosure on vegetation changes is very important. In this ...
Read More
In recent years the utilization rate of renewable resources especially the pressure of livestock grazing has increased. Uncontrolled livestock grazing has caused reduction of quantity and quality of forage, therefore, studying the effects of exclosure on vegetation changes is very important. In this research, the effects of exclosure on vegetation changes of Sahand rangelands were studied during 2001 to 2006. The vegetation changes were investigated inside and outside the exclosure area, using fixed transects. The results showed that total canopy cover and canopy cover of perennial grasses including Agropyrum trichophorum، Bromus tomentellus، Dactylis glomerata and Festuca ovina increased significantly inside the exclosure area (P<0.01). In terms of palatability, class I species increasedsignificantly (P<0.01). Cirsium haussknechtii, one of the important invasive species of the area, decreased significantly inside the exclosure area. There was no significant changes on total canopy cover of outside of the exclosure area. Canopy cover of perennial grasses and perennial forbs decreased (P<0.05) and shrubs canopy cover increased (P<0.01). Class I species decreased and class III species increased in outside of the exclosure area but it was not statistically significant. Canopy cover of Cirsium haussknechtii increased in outside of the exclosure area (P<0.05). No significant changes of soil organic matter were detected inside and outside of the exclosure area during six years.
Firoozeh Moghiminejad; Mohammad Jafari; Mohammad Ali Zare Chahooki; Yaser Ghasemi Arian; Asghar Kohandel
Volume 21, Issue 4 , March 2015, , Pages 643-650
Abstract
Exclosure is the prevention of livestock access to all or part of the rangeland for one year or a few consecutive years, performed with different goals. This research was aimed to investigate the effect of exclosure on soil physical and chemical properties as well as three main elements of N, P, and ...
Read More
Exclosure is the prevention of livestock access to all or part of the rangeland for one year or a few consecutive years, performed with different goals. This research was aimed to investigate the effect of exclosure on soil physical and chemical properties as well as three main elements of N, P, and K in Nazarabad region, Karaj. Soil sampling was performed in both sites of exclosure and grazing. Soil samples were taken from the beginning, middle and end of the four transects, established in each region, at two soil depths of 0-20 cm and 20-80 cm using systematic random sampling. The following soil properties were measured in the lab: pH, EC, organic matter, saturation percentage, and N, P, K. According to the obtained results, the effect of exclosure on soil N, P, and K was significant; however, exclosure had no significant effect on pH, organic matter and saturation percentage. Overall, our results clearly showed the positive impact of exclosure on soil physical and chemical properties.
Seyed Ali Hoseini; Jamshid Khatirnamani; Morteza Akbarzadeh
Volume 21, Issue 4 , March 2015, , Pages 685-697
Abstract
Studies on vegetation changes in rangelands, under grazing and exclosure conditions are important in planning range management programs. This research was aimed to investigate the changes in vegetation inside and outside three exclosures of Maraveh tapeh during 1997-2005. The canopy cover was measured ...
Read More
Studies on vegetation changes in rangelands, under grazing and exclosure conditions are important in planning range management programs. This research was aimed to investigate the changes in vegetation inside and outside three exclosures of Maraveh tapeh during 1997-2005. The canopy cover was measured each year, in several permanent plots, inside and outside the exclosure. To study the effects of precipitation on the changes of cover, the correlation between canopy cover of species and vegetative forms inside the exclosure and the precipitation of months and different vegetative stages were calculated. Results showed that total canopy cover in 2005 was significantly higher than that of 1997, both inside and outside the exclosure, mainly due to the increased cover of annuals. On the contrary, the cover of perennials decreased inside and outside the exclosure. Reduction in the cover of perennials was mainly related to grasses. In the last year of study, compared to the first year, total cover of class II species reduced drastically contrary to the cover of class III species. Although changes in canopy cover were influenced by precipitation, correlation coefficients were just significant for total canopy cover and vegetation cover of perennials. However, exclosure cannot be used as a method of range improvement in these rangelands. For rehabilitation of these areas, direct human intervention is necessary.
Anahita Rashtian; Ali Akbar Karimian
Volume 21, Issue 4 , March 2015, , Pages 747-755
Abstract
Investigation on the vegetation cover of rangelands under grazing and exclosure conditions is important in improvement of range management. Therefore, this research was aimed to investigate the effect of exclosure on production, density, frequency, importance value and vitally of Artemisia sieberi as ...
Read More
Investigation on the vegetation cover of rangelands under grazing and exclosure conditions is important in improvement of range management. Therefore, this research was aimed to investigate the effect of exclosure on production, density, frequency, importance value and vitally of Artemisia sieberi as the most important species of steppe rangelands of Iran. The study was conducted in Nodushan rangelands of Yazd province under grazing and exclosure conditions. Sampling was done randomly in both grazing and exclosure areas, with 10 transects and 40 quadrates of 1m2. In addition, 30 individuals of Ar. sieberi were selected randomly in each area and plant height, maximum and minimum diameter, canopy caver, vitality and dry matter production were measured. According to the obtained results, the studied species showed no significant differences for production, average diameter, height and canopy cover percentage. However, the vitally of Ar. sieberi showed significant differences between grazing and exclosure areas. The results of importance value indicated the increased relative importance of Ar. sieberi under moderate grazing intensity. The distribution pattern of Ar. sieberi under exclosure was uniform while under grazing condition a clumped distribution pattern was observed.
seyed akbar javadi; sonia khatibi baneh; hosein arzani; kazem saedi
Volume 22, Issue 4 , March 2015, , Pages 821-829
Abstract
This research was aimed to investigate the soil function indices in an exclosure region in comparison with non-exclosure. Then, using random plots as a control method, vegetation cover, stones and gravel, and litter were measured. Our results showed that the exclosure region (Saral Research Station) ...
Read More
This research was aimed to investigate the soil function indices in an exclosure region in comparison with non-exclosure. Then, using random plots as a control method, vegetation cover, stones and gravel, and litter were measured. Our results showed that the exclosure region (Saral Research Station) had better condition in terms of function indices in comparison with non-exclosure regions, indicating the positive impact of no livestock grazing for a long time. Northern slope of the exclosure region and the southern slope of non-exclosure region were identified as the most stable (60.26) and unstable (52.8) in the study area. The highest infiltration was recorded for the southern slope of the exclosure region (58.7), and the northern slope of the exclosure region had the highest nutrient cycling (45.63). The western slope of the exclosure region represented the longest inter patch in the whole landscape and the northern slope of exclosure had the largest area and number of ecological patches. Considering the area and number of patches helps the range manager detect the effect of exterior and interior factors on rangeland easier. Overall, long-term exclosure in the Saral region could be mentioned as a suitable method to reduce the runoff, soil erosion, and sediment production.
Nematollah Madadi Zadeh; Hossein Arzani; Ghavaloddin ahedi; Najmeh Faryabi
Volume 21, Issue 1 , June 2014, , Pages 128-138
Abstract
In the current study, the effects of exclosure were examined on rangeland vegetation at two study sites including, reference site (inside the exlosure) and critical site (outside the exclosure). Research was conducted by the systematic-random method and 160 2*1.5 m plots were established. Inside each ...
Read More
In the current study, the effects of exclosure were examined on rangeland vegetation at two study sites including, reference site (inside the exlosure) and critical site (outside the exclosure). Research was conducted by the systematic-random method and 160 2*1.5 m plots were established. Inside each plot, the percentage of canopy cover, litter, gravel and bare soil as well as density of class I, II, and III species were recorded. Dry matter yield was also calculated. Four-factor method and trend balance method were applied to determine the range condition and range trend, respectively. According to the obtained results, due to the exclosure, litter, yield, canopy cover percentage and class I species composition increased up to 24.72%, 37.42%, 23.6%, and 80.6%, respectively. On the other hand, the percentage of bare soil, gravel, and class III species composition decreased to 34.29%, 17.16%, and 26.96%, respectively. Mean differences in all parameters inside and outside the exclosure were significant at both study sites. Our results also indicated that exclosure led to the improvement of range condition and range trend.
Parvez Gholami; Jamshid Ghorbani; Maryam Shokri
Volume 18, Issue 4 , September 2012, , Pages 662-675
Abstract
Overgrazing can alter rangeland vegetation in different ways. In this study, we used diversity, species richness and plant functional groups as the alternative to assess the vegetation response to different grazing intensities. This was done under three grazing intensities (long-term exclosure as reference ...
Read More
Overgrazing can alter rangeland vegetation in different ways. In this study, we used diversity, species richness and plant functional groups as the alternative to assess the vegetation response to different grazing intensities. This was done under three grazing intensities (long-term exclosure as reference area, key area, and critical area) in rangelands of Mahoor Mamasani in Fars province. Vegetation sampling was carried out by random-systematic method and measuring the cover of plant species. The results showed that species diversity and richness significantly decreased with an increase in grazing intensity. Also, the cover percentage of Gramineae، Papilionaceae، Primulaceae، Umbelliferae and Valerianaceae significantly showed a negative response to grazing intensity while a positive response was found for Cruciferae، Labiatae، Plantaginaceae and Malvaceae. Moreover, some functional groups such as annuals, therophytes and Gramineae were significantly reduced from reference area to key area. The other finding of this study showed that decreaser plants significantly had less cover in critical area whereas increaser plants had greater cover in critical area. Species with storage of seeds in soil seed bank significantly had greater cover in aboveground vegetation in reference area than those species absent from soil seed bank. Due to the damage of some vegetation indices under overgrazing, it is recommended to make some changes in rangeland management and utilization in order to restore vegetation
Mirtaher Ghaemi; Mortezah Akbarzadeh; Shahram Abedi
Volume 19, Issue 1 , June 2012, , Pages 82-94
Abstract
Study of exclosure effects on vegetation changes under grazing and no grazing conditions in rangelands is of particular importance in range improvement programs. The reseach was performed in Semi- Steppe area of Bilehvar, Khoy from 1998 to 2006 . The vegetation cover was measured every year inside fixed ...
Read More
Study of exclosure effects on vegetation changes under grazing and no grazing conditions in rangelands is of particular importance in range improvement programs. The reseach was performed in Semi- Steppe area of Bilehvar, Khoy from 1998 to 2006 . The vegetation cover was measured every year inside fixed plots along the transacts. The results indicated the increase of total canopy cover inside the exclosure occurred during 9 years of the study, where the highest increase rates were observed with perennial cereals (>3.5 times), and with perennial broad-leaf forbs (>2.5 times). Outside the exclosure, the total canopy cover approximately remained unchanged and vegetative forms showed less changes. Inside the exclosure, favorable species appeared with a vegetation composition of about 19% . The proportion of increasers in the vegetation composition increased to more than double, however non-favorable species decreased to half. Outside the exclosure, desirable species were rare and the proportion of increasres increased to 28%. Average vegetation cover of annual plants inside the exclosure was higher than that of the outside, while average vegetation cover of the forbs compared to annual cereals were more predominant inside and outside the exclosure. During the study (9 years) in Bilehvar, a significant correlation was found between precipitation changes and canopy cover of the most species.
Maryam Rezashateri; Aadel Sepehri
Volume 17, Issue 4 , November 2011, , Pages 604-614
Abstract
This research was carried out to study the effect of livestock grazing on dynamics of vegetation patches in rangelands of Incheh Boroun, North Gorgan plain. To achieve this goal, the dynamic parameters including the length of vegetation patches and bare area distances between consecutive vegetation patches ...
Read More
This research was carried out to study the effect of livestock grazing on dynamics of vegetation patches in rangelands of Incheh Boroun, North Gorgan plain. To achieve this goal, the dynamic parameters including the length of vegetation patches and bare area distances between consecutive vegetation patches inside and outside the enclosure were measured. First of all, a random point was selected outside the exclosure as starting point and then 11 transects with 50 meters length were placed in a randomized sequential order. The length of vegetation patches and free vegetation spaces were recorded along each transect. Sampling inside the exclosure was done similarly through setting up six 50-meter transect Results showed significant differences in length of vegetation patches, inter patches and ratio of vegetation patches length to inter patches length in both studied regions. Overgrazing outside the exclosure was considered for this result. Since environmental stresses reveal their impacts through changing the shape, frequency and size of vegetation patches, it seems that studying the length of vegetation patches and inter patches has high accuracy and can be done with relatively less time and costs. In addition, it could well represent dynamic changes of plants in response to environmental stresses and desertification process.
Farhad Aghajanloo; Mortezah Akbarzadeh; Ahmad Musavi
Volume 16, Issue 4 , January 2010, , Pages 493-504
Abstract
As the documents and reports reveal, the condition of rangelands of Iran is poor or very poor in most areas; therefore, the percentage of invader species is dominant. The study of vegetation changes under strict exclosure and grazing is critical to understand the extreme problems of rangelands of Iran. ...
Read More
As the documents and reports reveal, the condition of rangelands of Iran is poor or very poor in most areas; therefore, the percentage of invader species is dominant. The study of vegetation changes under strict exclosure and grazing is critical to understand the extreme problems of rangelands of Iran. The effect of exclosure and grazing was studied on the direction of vegetation changes of rangelands at Arquin site of Zanjan province at 1450 meter above sea level from 2001 to 2006. Three fixed pairs of transects with a total number of 60 plots were established inside of exclosure area and outside too. The annual forage production was measured by randomized plots. Comparison of the data in first and last years of the study were done by T student sample test. The results showed that the total canopy cover of Arquin exclosure is increased inside in comparison with outside, and it is statistically significant (P<0.01). The response of growing forms to exclosure and grazing was different, and the canopy cover of Astragalus achtalensis (P<0.05) and Stipa barbata (P<0.01) increased significantly in 2006 in comparison with 2002. The vegetation composition changed also in the study area. The relative increase of increasers in last year, was by 160 percent to that of the first year inside the exclosure; whereas the changes were not apparent. The rate of plant production was specially depended on precipitation fluctuation and the amount of organic mater and nitrogen content at 0 to 15 cm of soil depth inside and outside of the exclosure and that of 15-30 cm outsid has been increased significantly.
Ghasem Asadian; Morteza Akbarzadeh; Mohammad reza Sadeghimanesh
Volume 16, Issue 3 , December 2009, , Pages 343-352
Abstract
Study of vegetation changes of grazed and ungrazed rangelands is most important in range management programs. Vegetation changes were studied for four years (1996-99) inside and outside of the exclosure in Gian rangelands of Hamadan province. Measurements were made in permanent plots that have been established ...
Read More
Study of vegetation changes of grazed and ungrazed rangelands is most important in range management programs. Vegetation changes were studied for four years (1996-99) inside and outside of the exclosure in Gian rangelands of Hamadan province. Measurements were made in permanent plots that have been established in study areas since 1996. Forage production was measured in randomized plots each year. Data were compared whit T test analysis. Results showed that there were significant differences in total cover of perennials during study period inside exclosure and the cover increased about 80 percent. The cover of all plant forms, such as shrubs, grasses and forbs increased significantly inside the exclosure in this period. The cover of perennials increased about 16 percent outside of exclosure during this period too, but there were significant differences in shrubs and grasses and no difference in forbs. Decreasers and increasers increased and invaders decreased inside, but outside of exclosure there was an opposite trend. Frequency of good quality plants increased inside and decreased outside. Range condition increased from poor to fair inside and decreased to very poor outside of exclosure. A positive and negative trend was observed inside and outside the exclosure area. In second year of study, rainfall was greater and In final year annual precipitation was more than first year but seasonal rainfall that is effective in growth, was less than the first year. Relationship between species canopy cover and annual and seasonal rainfall evaluated, however the correlation coefficient between rainfall and some species was significant. Overall, in comparison inside and outside, exclosure improved vegetation condition, forage production and range condition, under this climatic condition. Because of good precipitation condition of these years, it is necessary to continue the study to cover a series of drier years.
Morteza Akbarzadeh; Mohammed Reza Moghadam; Adel Jalili; Mohammad Jafari; Hossein Arzani
Volume 13, Issue 4 , February 2007, , Pages 324-336
Abstract
The pressure of livestock grazing and overall utilization of rangelands have caused vegetation and soil degradation in many natural rangelands of Iran. Grazing prevention is one of the rangelands rehabilitation methods, which is effective in renovation of rangelands. The effect of 24 years of grazing ...
Read More
The pressure of livestock grazing and overall utilization of rangelands have caused vegetation and soil degradation in many natural rangelands of Iran. Grazing prevention is one of the rangelands rehabilitation methods, which is effective in renovation of rangelands. The effect of 24 years of grazing protection were studied on vegetation dynamics of Kuhrang region, in two years growing seasons (2003 and 2004). Parameters from rangelands characteristics were collected and analyzed. Results showed that after 24 years livestock exclusion in Kuhrang, total inside canopy cover was higher than outside (P<0.01). Grasses and forbs were higher inside than outside (P<0.01), but shrubs were not significantly different (P>0.05). Over half of inside canopy cover belonged to decreasers and increasers, which were little or negligible outside of exclosure and 95 percent of outside plant composition belonged to invaders. Most desirable species had greater inside cover than outside(P<0.01). Klucia odoratassima, Scorzonera calyculataand Delphinium cyphoplectrumhad greatest inside canopy cover, than other forbs. More than half of inside and 95 percent of outside cover referred to decreasers and increasers. Approximately 38 and 1.2 % of inside and outside forage production belonged to decreasers and increasers respectively. Regeneration was higher outside of exclosure in Astragalus adscendens, in first year. Litter was higher inside and bare soil outside the exclosure (P<0.01). Inside and outside range condition was good and very poor, respectively.
Naser Baghestani Maybodi; Mohammad taghi Zare; Jalal Abdollahi
Volume 13, Issue 4 , February 2007, , Pages 337-346
Abstract
Study over vegetation on grazed and ungrazed rangelands is significant for range managemen, this the effects of 2-decade exclusion on vegetation of steppic rangelands in Nir range research station were studied. Three 7.5-hectare experimental plots were selected inside and outside of the exclosure. Exclosure ...
Read More
Study over vegetation on grazed and ungrazed rangelands is significant for range managemen, this the effects of 2-decade exclusion on vegetation of steppic rangelands in Nir range research station were studied. Three 7.5-hectare experimental plots were selected inside and outside of the exclosure. Exclosure site had not been grazed from 1986 to 2004. The adjacent site was continuously grazed at the same time. Cover estimated on quadrates and forage yield were measured by clipping and weighting method. Data were analyzed by t-test method. Results showed that cover, density and yield of Salsola rigida and Stipa barbata increased significantly inside exclosure (p<0.01), but it was not significantly different in Artemisia sieberi (p>0.05).Cover, density and yield of Scariola orientalis , Launaea acanthodes and Noaea mucronatawere greater in grazed area, but only the yield of first species, density of second species and cover and density of third species were significantly high (p<0.05). Two-decade protection from grazing showed that vegetation trend is very slow in arid rangelands.
Jamshid Khatir Namani
Volume 14, Issue 1 , January 2007, , Pages 88-96
Abstract
Study of vegetation changes of grazed and ungrazed rangelands is important in range management programs. In order to do this, Chut rangelands located between Dashly Boroon and Maravehtappeh of north Golestan province chosen as the study area. Chut rangeland is saline with slow drainage and 180 mm annual ...
Read More
Study of vegetation changes of grazed and ungrazed rangelands is important in range management programs. In order to do this, Chut rangelands located between Dashly Boroon and Maravehtappeh of north Golestan province chosen as the study area. Chut rangeland is saline with slow drainage and 180 mm annual precipitation. Vegetation type of this rangeland is Poa bulbosa- annual grass and forbs. Two sites of grazed and ungrazed area were selected and factors such as soil erosion, canopy cover, plant composition and vigority of plants were measured and recorded for five years. Results showed that forage production and density of annual grasses and forbs increased inside the exclosure. There was no significant difference between vegetation cover percentage and outside the exclosure (grazed and ungrazed rangelands). Generally, the results indicated that vegetation changes in the study area are slow and gradual.
Morteza Akbarzadeh; Taghgi Mirhaji
Volume 13, Issue 3 , February 2006, , Pages 222-235
Abstract
Study of vegetation changes of ungrazed rangelands is important. It is supposed that ungrazed areas tends toward climax and range condition to be improved. The major portion of our rangelands are laied in arid and semi-arid regions. For that precipitation is the major influential factor on vegetation ...
Read More
Study of vegetation changes of ungrazed rangelands is important. It is supposed that ungrazed areas tends toward climax and range condition to be improved. The major portion of our rangelands are laied in arid and semi-arid regions. For that precipitation is the major influential factor on vegetation changes. In dry years as rainfall decreases, the vegetation cover are damage. This study were conducted on Rudshur rangelands for nine years (1996-2004), with the aim of rainfall variation and ungrazed condition effects on vegetation changes. Plant parameters as canopy cover, density and seedling numbers were estimated on permanent plots each year. A dry period were started in 1997 in the region and continued for five years. Results showed, in a period of nine years, total canopy cover declined 40 percent. Decline of canopy cover varied from 26 to 95 percent for different species. Only canopy cover of the Poa sinaica increased about three times, due to earliest vegetative period in growing season. Decline in canopy cover was greatest in forbs, and grasses had lower decline. Regeneration was high in the rainy years and 81 percent of total seedlings belonged to grasses especially to Stipa hohenackeriana. Density of most species decreased in the study period especially in dry years.
Zabihollah Eskandari; Sattar Chavoshi
Volume 9, Issue 3 , September 2001, , Pages 943-958