morteza Khodagholi; Razieh Saboohi; Alireza Eftekhari; Mina Bayat
Volume 31, Issue 4 , January 2025, , Pages 363-381
Abstract
Background and purpose:Increasing awareness of the environment and efforts for sustainable management of natural resources require study and monitoring in different time scales and places. Continuous changes should be considered as an inseparable part of any ecosystem. As natural ecosystems, rangelands ...
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Background and purpose:Increasing awareness of the environment and efforts for sustainable management of natural resources require study and monitoring in different time scales and places. Continuous changes should be considered as an inseparable part of any ecosystem. As natural ecosystems, rangelands are not exempt from this issue. So that rangeland monitoring is necessary in the sense of continuous investigation of these lands with regard to the ecological importance, economic functions and constant changes of these resources. Access to such data is extremely important both for national planning and for the use of rangelands, and it provides the basis for the use of advanced facilities such as remote sensing. Based on this, in order to monitor the trend and intensity of changes in vegetation cover and soil indicators of rangelands for 4 years at the Goorab site located in Isfahan province, it was evaluated and monitored.Materials and methods:The site of Goorab Fereydoonshahr Isfahan is located 230 kilometers west of Isfahan city and 35 kilometers west of Fereydoonshahr city. Plant factors including canopy cover of plant species and production rate of plant species and percentage of dead leaves were evaluated. Evaluation was done in the first year by random-systematic method and in the following years systematically with sufficient number of samples and appropriate distribution of samples in the plant type determined at the time of rangeland preparation. Soil sampling was done in theResults:The results showed that the 4-year average vegetation canopy cover percentage of Goorab site is about 42.2%, and the highest and lowest coverage is 59.4% in 1398 and 31.6% in 1400, respectively. The production rate is 1374.2 kg of dry matter per hectare. The production, like the canopy cover percentage, shows a lot of changes during the 4-year evaluation at the Goorab site, so that in 2019, the production reached 1957 kg per hectare, and in 2021, it decreased by 50% compared to 2019 to 955.7 kg per hectare. The results of the correlation and regression test also showed that the amount of precipitation in the growing season had the highest correlation with the amount of crown cover and production of plants in the region.Conclusion:Considering the importance of rangelands, both in terms of production and in terms of environmental values and services they provide to the society, studying the changes of rangelands in terms of the aforementioned factors and knowing the factors of those changes will be an effective help in developing a basic management plan and sustainable use of rangelands.
Sajad Amiri; Ghasem Khodahami
Volume 28, Issue 2 , June 2021, , Pages 296-307
Abstract
Three perennial grasses Stipa arabica, Elymus pertenuis, Hordeum bulbosum, were selected under rainfed conditions in semi-steppe habitats of Fars province. Seeds of 15 populations of these three species (five species of each genus) were collected in 12 habitats and an elevation profile of 1700 to 2600 ...
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Three perennial grasses Stipa arabica, Elymus pertenuis, Hordeum bulbosum, were selected under rainfed conditions in semi-steppe habitats of Fars province. Seeds of 15 populations of these three species (five species of each genus) were collected in 12 habitats and an elevation profile of 1700 to 2600 meters above sea level located in seven cities. Each population included 120 pots (1800 pots in total) at the preparation station, and seeds (three seeds per pot) were planted in pots. In the third year, after preparing the main land, seeds were sown in three rows in each plot based on a completely randomized block design. Necessary assessments were made after species emergence based on canopy cover, plant height, forage production, seed production, and longevity. The results showed that Hordeum bulbosum with 471.67 kg seed production and 539.20 kg forage production per hectare had the highest yield, and Stipa arabica species with 1642 cm2 and 92.60% had the highest canopy cover and vigor, respectively.
Sajad Amiri; qasem khodahami
Volume 27, Issue 3 , October 2020, , Pages 504-515
Abstract
Three perennial grass species, Stipaarabica, Elymus pertenuis, and Hordeum bulbosum, were selected in the semi-steppe habitats of Fars province, and seeds of 15 populations of these three species (5 species of each genus) in were collected 12 habitats. For each population, 120 pots (a total of 1800 pots) ...
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Three perennial grass species, Stipaarabica, Elymus pertenuis, and Hordeum bulbosum, were selected in the semi-steppe habitats of Fars province, and seeds of 15 populations of these three species (5 species of each genus) in were collected 12 habitats. For each population, 120 pots (a total of 1800 pots) were prepared and the seeds (three seeds per pot) were planted. In the third year, after preparing the main land, seeds were planted in three rows in each plot based on a completely randomized block design. Necessary evaluations after emergence of the species were performed based on the cover canopy area, plant height, forage production, seed production, and vigor. The results showed that Hordeum bulbosum with seed production of 471.67 kg and forage production of 539.20 kg/ha had the highest production, and Stipa arabica had the highest canopy cover (1642 cm2) and vigor (92.60%). Elymus pertenius had the highest forage production (460.93 kg/ha) and canopy cover (1447 cm2).
Ali Akbar Karimian; Samira Hossein Jafari
Volume 27, Issue 1 , April 2020, , Pages 36-46
Abstract
To manage an animal species effectively, it is necessary to identify habitats with high suitability for it; So its population can be preserved by conserving those habitats and planning to manage them properly. For this purpose, the study was done to determine Relationship between rangeland species and ...
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To manage an animal species effectively, it is necessary to identify habitats with high suitability for it; So its population can be preserved by conserving those habitats and planning to manage them properly. For this purpose, the study was done to determine Relationship between rangeland species and habitat suitability of Gazella subgutrrosa in different seasons on the basis of dung groups in Kalmand plain of Yazd province. So, sampling was done using random steady plots with 200 meters long and 2 meters wide and with 2 replications during five field investigation in summer and autumn. Random and control plots were put in different directions and were investigated every 45 days. Finally, all maps needed and information incorporation were prepared and done in ArcGIS9.3. The results showed that there is no difference in two seasons related to dung groups' density. In terms of canopy cover percentage, Artemisia species had a significant increase in presence points compared to random points; Astragalus sp. had also a significant increase in presence points compared to control points. Onopordon sp. canopy cover in absent points and Acanthophyllum sp. in random points were higher than in presence points (p<0.01).according to the prepared map, 23% of the region has topnotch suitability and 47% has second best suitability. Rocks and the regions under human activities were identified as unsuitable habitats. According to the results, it is seems that from habitat variables, species richness, Artemisia cover percent and distance from road are effective on deer habitat.
Morteza Akbarzadeh
Volume 12, Issue 2 , September 2019, , Pages 167-188
Nahid Azizi; Hamed Joneidi; Khaled Osati
Volume 26, Issue 3 , September 2019, , Pages 717-730
Abstract
This research monitored changes in canopy cover percentage of typical species during a 10-year period in the Ghosheh rangelands to find out the relationship between two important climate variables (precipitation and temperature) and canopy cover changes. Therefore, the canopy cover ...
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This research monitored changes in canopy cover percentage of typical species during a 10-year period in the Ghosheh rangelands to find out the relationship between two important climate variables (precipitation and temperature) and canopy cover changes. Therefore, the canopy cover percentages of six typical species (separately) and annual species (overall) were measured during 10 years at the end of growing season in thirty 2-m2 plots, distributed along two 250–m transect lines. The results demonstrated that the maximum canopy cover percentage for water year 2006-2007 (wet-year) and the minimum value for water year 2012-2013 (drought) were 15% and 5.5%, respectively. The canopy cover percentage modeling was performed based on linear regression method using precipitation and temperature variables. The precipitation of April explained 65% of changes in canopy cover percentage of A. sieberiat 95% confidence level (RRMSE = 0.26 & MAE=0.49). The best simple linear regression model for estimating canopy cover percentage of S. barbata and Z. eurypterum was introduced by total precipitation of March-June and precipitation of March, representing 77% (at 99% confidence level) and 67% (at 95% confidence level) of changes in canopy cover, respectively. Considering the dominant role of A. sieberi, S. barbata and Z. eurypterum in vegetation composition of study areas, it can be concluded that most changes in canopy cover of the studied rangeland are predictable by variabilityofprecipitation during growing seasons.
Ebrahim Atarod; Naser Baghestani; Jalal Barkhordari; Ali Beman Mirjalili
Volume 25, Issue 2 , August 2018, , Pages 289-297
Abstract
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 ...
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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.
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 ...
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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.
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 ...
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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.
Masoud Borhani; Hosein Arzani; Mehdi Basiri; Mohammad Ali Zare Chahouki; Mehdi Farahpour
Volume 21, Issue 3 , December 2014, , Pages 530-540
Abstract
In order to investigate the effects of range management plans on cover, production, litter, and regeneration of plants in Semirum rangelands, 54 sites including 29 with plan and 25 without plan were selected. The implementation of range management plans resulted in the decrease of stocking rate, affecting ...
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In order to investigate the effects of range management plans on cover, production, litter, and regeneration of plants in Semirum rangelands, 54 sites including 29 with plan and 25 without plan were selected. The implementation of range management plans resulted in the decrease of stocking rate, affecting the improvement of vegetation. According to the obtained results, no significant differences were found for the mean total cover, production and number of seedlings between two managements (P<0.05), while in the sites with plan, the cover, production and number of seedlings of class 1 plants, and cover and production of perennial grasses were significantly more than those of the sites without plan. This result was also true in the case of litter. These variations in plant composition were due to the impact of controlling the intensity and timing of grazing on the competition between palatable and perennial species with invasive and annual ones.
Zeinab Jafarian; Mansoureh Kargar; Jamshid Ghorbani
Volume 21, Issue 2 , August 2014, , Pages 234-236
Abstract
Spatial variability and heterogeneous geographical distribution of soil physical and chemical properties in rangeland ecosystems are affected by physical and biological factors including different managements, soil microclimate and topography, leading to the vegetation changes. Therefore, this research ...
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Spatial variability and heterogeneous geographical distribution of soil physical and chemical properties in rangeland ecosystems are affected by physical and biological factors including different managements, soil microclimate and topography, leading to the vegetation changes. Therefore, this research was aimed to study the spatial variability of production, density and canopy cover of Artemisia aucheri in the line with some soil properties variability in Vavsar rangelands of Kiasar. The sampling method was random-systematic. A total of five transects of 100m length were selected in the study area with a distance of 100m on which 10 plots of 2m2 were established with a distance of 10m. Soil samples were taken from a depth of 0-15 in each plot. In addition, production, density and canopy cover of Artemisia aucheri were measured in each plot. According to the results of geostatistical analysis in GS+ software, the percentage of clay and the density of Artemisia aucheri, showed the highest variation coefficients with the values of 82% and 53%, respectively. The variograms' amplitude varied from 196.2m for production to 910m for the percentage of moisture, lime, EC, and canopy cover. According to the results of cross validation, the models of lime percentage, density and production of Artemisia aucheri showed spatial correlation, and, consequently, had higher accuracy to be used in Kiriging interpolation.
Maryam Haji Mohammad Ebrahim Zanjani; Hosein Arzani; Nematalah Khorasani; Navid Ziaee
Volume 19, Issue 2 , September 2012, , Pages 191-202
Abstract
Distinguishing of protected areas is one of the range management methods for improvement, sustainable development and richness of plant composition. This research was carried out to study the effects of conservation on some vegetative factors in some parts of Varjin located in Tehran province and protected ...
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Distinguishing of protected areas is one of the range management methods for improvement, sustainable development and richness of plant composition. This research was carried out to study the effects of conservation on some vegetative factors in some parts of Varjin located in Tehran province and protected since 1982. For this purpose, two vegetation types were selected in protected area as well as unprotected area. Four transects of 300 m length were then established in key areas of each vegetation type and 10 plots of 1m2 were sampled along each transect with 30-m intervals. In each plot, list of species was recorded and vegetative factors including density, composition and yield (cut and weighting method) were measured. All samples were weighted in wet and dry condition. Normality of data was tested and then measured parameters were compared by t test. Results showed that mean difference for all measured parameters in vegetation type of (Me Pe – As br) except vegetation composition of class III species and density of class II and III species were significant. Also in vegetation type of (Fe ov – As br), all parameters were significant except density of class I and class III species.
Jallal Abdolahi; Hossean Arzani; Mohammad hosein Savaghebi; Mojgan Azimi; Hosein Naderi
Volume 19, Issue 1 , June 2012, , Pages 45-59
Abstract
Our country’s rangelands are mainly located in arid and semi-arid regions. Due to the low amount of precipitation and high rate of evapotranspiration, water stress is considered as the most crucial environmental stress for vegetation in this region. This study was conducted at Khud-e-sofla ...
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Our country’s rangelands are mainly located in arid and semi-arid regions. Due to the low amount of precipitation and high rate of evapotranspiration, water stress is considered as the most crucial environmental stress for vegetation in this region. This study was conducted at Khud-e-sofla rangelands for nine years (1378- 1386) to investigate the effect of precipitation fluctuation on canopy cover and production of important plant species. For this purpose, four dominant species were selected and their canopy cover and production were monitored every year in permanent and random plots, respectively. Precipitation data were collected from the nearest synoptic station. According to the data of precipitation, cumulative rain amount was calculated at various periods. The relationship between variables of plant parameters and cumulative rain amount was analyzed by step wise regression method in SPSS 13. The results showed that plant species often reacted to the precipitation fluctuations. However, various species reacted differently to the precipitation fluctuation in terms of cover and production. The total vegetation cover as well as canopy cover of Artemisia aucheri hada negative and significant correlation with winter precipitation.Whereas, precipitation of January to April and the past year precipitation exhibited a high correlation with canopy cover of Iris songarica and Stipa barbata. The forage production was also influenced by seasonal precipitation. According to the results, total yeild and the yield of Artemisia aucheri, Lactuca orientalis, Stipa barbata could be estimated by precipitation data While, estimation of forage production through the precipitation data was not enough accurate for Iris songarica.
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 ...
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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.
Elham Fakhimi abarghoie; Mansur Mesdaghi; ghasem ali Dianati tilaki
Volume 18, Issue 2 , September 2011, , Pages 219-230
Abstract
The large scale degradation of rangelands in Iran can be largely attributed to overgrazing. So investigation on the effects of grazing on vegetation parameters is vital to control the rangeland ecosystems degradation. The object of this study is to investigate the effect of heavy, moderate, and ...
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The large scale degradation of rangelands in Iran can be largely attributed to overgrazing. So investigation on the effects of grazing on vegetation parameters is vital to control the rangeland ecosystems degradation. The object of this study is to investigate the effect of heavy, moderate, and light grazing intensity on production, canopy cover, litter, stone, grovel and bare soil in steppe zone of central Iran (Nodushan summer rangelands). For this research, stratified systematic-random sampling was use in a completely randomized block design. On each plot of 2m2, canopy cover percentages and density of plant species, dry matter of palatable species, litter, stone, grovel, and bare soils were estimated. Classification of the sampling site was based on TWINSPAN (Two Ways Indicator Species Analysis). In order to study the effects of grazing intensities on vegetation parameters and their relationships with the distance of watering points, ANOVA and Pearson’s correlation were employed. By using of TWINSPAN, the samples were classified in to, 3 groups. Results were shown that canopy cover percentage of palatable plants and production at different grazing pressure were significant (P<0.05). Litter percentage, stone, grovel, and bare soil percentages of heavy grazing was significantly different with moderate and light intensities of grazing (P<0.05). Canopy cover percentage of unpalatable plants and density of plants were not significant at three different grazing pressure (P>0.05).
Rooh... Kazemi; Hassan Yeganeh; Jamal.. Khajedin
Volume 18, Issue 1 , May 2011, , Pages 124-138
Abstract
Accurate and up-to-date global land cover data sets are necessary for various global change research studies including climatic change, biodiversity conservation, ecosystem assessment, and environmental modeling. The aim of the present research was to study change detection of vegetation during the grazing ...
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Accurate and up-to-date global land cover data sets are necessary for various global change research studies including climatic change, biodiversity conservation, ecosystem assessment, and environmental modeling. The aim of the present research was to study change detection of vegetation during the grazing season using multi temporal data of WiFS in Semirom region. Various preprocessing, including geometric correction were applied using topographic maps of 1:250000 with an RMSe 0.35 pixel for sensor IRS-WiFS. The atmospheric and topographic corrections were carried out using dark-object subtraction method and the Lambert method. Field data collection was started on June 2005 on 800,000 ha. Multi-temporal data of IRS-WiFS sets were used for this study. Image processing including FCC, PCA, vegetation indices and supervised classification were employed to produce the vegetation canopy cover map. Various vegetation types were sampled using stratified random sampling method. twenty random sampling points were selected and canopy cover percentage was estimated. Digital data and the indices maps were used as independent data and the field data as dependent variables. The produced models were processed and then resulted images were categorized in 5 classes. Also post classification method was used to determine change detections. Finally the produced maps were controlled for their accuracies. The results confirmed the high correlations of used WiFS indices with field data. In the current study, more than 30 percent of the study area has been affected during the grazing season. Also the NDVI, SAVI and DVI indices which employ RED and NIR bands had relatively highly correlations with rangeland data. Result showed vegetation maps produced with IRS-WiFS data set had very high accuracy.
Jamal Emani; Ali Tavili; Essa Bandak; Mohammad Khosravi
Volume 17, Issue 2 , September 2010, , Pages 234-242
Abstract
Flood water spreading projections have been done with many objectives. One of these objectives is increasing vegetation cover. Flood water spreading leads to the increasing of soil moisture and as a result increasing forage production. In this study the effects of flood spreading are evaluated. This ...
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Flood water spreading projections have been done with many objectives. One of these objectives is increasing vegetation cover. Flood water spreading leads to the increasing of soil moisture and as a result increasing forage production. In this study the effects of flood spreading are evaluated. This assessment is done in aquifer of Mayhem district of Ghorveh state. In each rainfall that results into flood, 6 areas are flooded and 2 areas are not flooded. Therefore, 6 areas considered as the flood water spreading and 2 areas considered as the control site. The samplings of vegetation properties were performed in these eight areas. For this purpose, in each district, 5 transects each with a length of 100 m with 10 m interval from each other were situated and along each transect, 10 quadrates with an area of 1m were established. In each area, the characteristics of canopy cover percentage, forage production and species density were recorded. Analysis of data was performed using of un-paired T-test. Obtained results from T-test indicated that there is significant difference between canopy cover percentage (p≤ 0/1) and forage production (p≤ 0/05) while no significant difference was observed for species density in flooded and non-flooded areas. The results showed that the canopy cover increased from 41/91 percent in the control site to 62/18 percent in the flood spreading area. The forage production increased from 467/17 kg/ha in the control site to 632/17 kg/ha in the flood spreading area. Also the species density increased from 1/18 in the control site to 1/59 in the flood spreading area. Some of the plant species that are in the III classes from palatability aspect, decreased in the flood spreading area rather than control site.
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. ...
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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 ...
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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.
Ghader Karimi; Saadat Mozafari; Mansour Nikbakht
Volume 16, Issue 3 , December 2009, , Pages 353-361
Abstract
The pressure of livestock grazing and overall utilization of rangelands have caused vegetation and siol degradation in many natural rangelands of Iran. Changes of canopy cover, species composition, forage production, in Margoon station were studied. In this study cover estimated by quadrates and forage ...
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The pressure of livestock grazing and overall utilization of rangelands have caused vegetation and siol degradation in many natural rangelands of Iran. Changes of canopy cover, species composition, forage production, in Margoon station were studied. In this study cover estimated by quadrates and forage yield were measured by clipping and weighting method. Results showed that species diversity in this region was relatively good (about 31 species). Palatability class I, II and III were 12.6, 27.5 and 9.5 percent respectively. Cover, density and yield of Bromus tomentellus and Hordeum bulbosum increased inside the station (enclosure). Also, canopy cover changed from 33.4 to 55.5 percent. Forage production increased from 309 to 569.8 Kg/ha due to management practices.
Naser Baghestani Maybodi; Mohammad taghi Zare; Mohammad Abolghasemi
Volume 14, Issue 4 , February 2008, , Pages 478-489
Abstract
Wilted and dried up stands of haloxylon aphyllumspecies in afforested areas of Yazd has allways been a focal point of natural resources experts. Using various pruning treatments, the effect of pruning on the wideness of canopy cover and vigor of 12-year-old semi-trees of haloxylon aphyllumhad been evaluated ...
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Wilted and dried up stands of haloxylon aphyllumspecies in afforested areas of Yazd has allways been a focal point of natural resources experts. Using various pruning treatments, the effect of pruning on the wideness of canopy cover and vigor of 12-year-old semi-trees of haloxylon aphyllumhad been evaluated formerly. That study had been conducted in two different sections of the forest in the winter of years 1994. One section had shown a tree-density of 125 semi-trees per hectare, and the other had represented a tree-density of 250 semi-trees per hectare. The treatments included cutting at different heights of 70, 35, 10 cm and also no cutting (control). The results of that previous six-year study (1994-2000) showed that pruning increased vigority and regrowth of plants treated with different levels of pruning. The 35-cm pruning treatment was preferred over other treatments. At the end of growing season of year 2005, eleven years after pruning treatments, the same trees were evaluated for the second time. Results of the new study (in 2005) showed that while non-pruning (control) 23-year-old semi-trees are wilted and almost dried up, the semi-trees with pruning are vigorous and healthy. In terms of canopy cover and height, no significant difference was found between trees with different pruning treatment in the 5 years of 2000-2005. There was a significant reduction in the canopy cover and height of non-pruning (control) semi-trees (p<0.05). For the semi-trees which had been cut at a height of 35 cm, the diameter of canopy and the height were 262 and 164 cm, respectively. This semi-trees showed a good resistance against movement of sands and sand dunes.
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 ...
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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.
Ali Hoseini; Amrali Shahmoradi; Ghasemali Abarsaji
Volume 14, Issue 2 , January 2007, , Pages 110-123
Abstract
One of the halophyte plant species in the rangelands of Golestan Province is Halocnemum strobilaceum which grows in areas of saline and alkaline soils with shallow water table. It belongs to Chenopodiaceae family. It is named Cheraton by local people and covers 167,000 hectare of the province area. ...
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One of the halophyte plant species in the rangelands of Golestan Province is Halocnemum strobilaceum which grows in areas of saline and alkaline soils with shallow water table. It belongs to Chenopodiaceae family. It is named Cheraton by local people and covers 167,000 hectare of the province area. Five study sites which are named Gomishan, Sangar-tapeh, Soficom, Incheh-shoreh-zar, and Incheh-boroon were selected to conduct the study. A formula of L = 2D + d was used to calculate a proper size of measuring plots. Letter D represents the diameter of plant and letter d represents the distance between individual plants. For each site, three transects and thirty plots were used to measure canopy cover, density, frequency, and the proportion of this species in plant composition. Also the weight of above-ground production and roots were measured. The size of plots in Gomishan, Sangar-tapeh, Soficom, Incheh-shoreh-zar, and Incheh-boroon were 1, 2, 2, 2, 4 square meters, respectively. The results showed that, in terms of canopy cover, density, regeneration, above-ground production, and root production of this range plant, there are significant differences among different sites. This plant showed the most (%26) and the list (%6.46) canopy cover in Gomishan and Incheh-boroon study sites, respectively. It also showed the most (59300/ha) and the list (5250/ha) density in Gomishan and Incheh-boroon study sites, respectively. The frequency of plant was %86.6 to %96.6 in different sites. The plant formed %50.93 to %65.53 of the plant composition in different study sites. The most above-ground and root production were found in Incheh-boroon area.
Jalal Abdollahi; Hosein Arzani; Naser Baghestani; Fakhr.... MirAskarshahi
Volume 13, Issue 2 , February 2006, , Pages 74-81
Abstract
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 ...
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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.
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 ...
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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.