Saeed Abdollahzadeh; Marzieh Rezaie; Rasoul Mahdavi
Volume 31, Issue 2 , August 2024, , Pages 204-218
Abstract
IntroductionThe distribution of plants in different habitats is influenced by environmental and edaphic conditions. Identifying the relationship between soil factors and vegetation, as well as the specific soil characteristics in which these species are found, is one of the important goals of this research. ...
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IntroductionThe distribution of plants in different habitats is influenced by environmental and edaphic conditions. Identifying the relationship between soil factors and vegetation, as well as the specific soil characteristics in which these species are found, is one of the important goals of this research. Taking steps in this direction will help prevent habitat destruction and facilitate the restoration of damaged areas. Let me know if you need any further adjustments! Materials and methods The study identified three representative areas using the physiognomic-systematic method, focusing on the habitat of Ferula assafoetida L. Areas with less than 15% coverage were classified as low-density, those with 15-30% coverage as medium-density, and areas with more than 30% coverage as high-density. In each representative area, eight transects of 1000 meters were systematically established and positioned perpendicularly to each other. To account for slope variations in sampling, quadrat sampling along the transects was employed. The plot size was determined using the minimum level method, with species density measured in 2 x 2 square meter plots across a total of 240 plots. To prepare soil samples, two soil profiles were dug at a distance of 500 meters along each transect, resulting in a total of 48 profiles from which soil samples were collected at depths of 0 to 30 cm. In each representative area, three transects of 1000 meters were placed perpendicularly, with ten sampling bases spaced 100 meters apart along each transect. The collected samples were transported to the Water and Soil Laboratory of Hormozgan University for analysis. The amount of gum collected from each base was measured using a digital scale with an accuracy of 0.001 grams. A comparison of the production of this plant gum was conducted across the different habitats. The changes in edaphic factors in representative areas were analyzed using SPSS software with the GLM test, revealing low density at 15.8 bases per hectare, medium density at 27.8 bases per hectare, and high density at 46.9 bases per hectare of Ferula assafoetida L. Results In the areas with low density, the soil acidity level was measured at 7.4, while in the medium-density area, it was 7.8, and in the high-density area, it reached 8. These results indicate that soil acidity is higher in densely populated areas and lower in areas with low density, suggesting that Ferula assafoetida is more compatible with alkaline soils. As soil acidity increases, the density of this plant decreases. The analysis of density changes in relation to organic matter percentage showed that organic matter has a direct effect on plant density; as organic matter increases, so does the density of the plant. Conversely, when the soil has low organic matter content, the density of Ferula assafoetida declines. Additionally, the comparison of average potassium levels revealed that the low-density area had the lowest potassium content, while the high-density area had the highest. The combined levels of calcium and magnesium were also lowest in the low-density area and highest in the dense Angozeh habitat. Furthermore, the number of Ferula assafoetida bases per unit area increased in regions with higher sand content, whereas the number of bases decreased in clay soils. This plant is not compatible with saline or acidic soils. ConclusionUnderstanding the ecological needs and performance of plant species is essential for implementing remedial activities in dry and desert ecosystems. Bestak city, located in Hormozgan province, is home to numerous Anghuzeh plantations, which have the potential to produce gum, generate currency, and provide significant economic value for local communities. The region is characterized by elevations ranging from 1900 to 2500 meters. This species exhibits a greater geographical distribution in areas with sand, silt, and high acidity, with increased density and decreased distribution in clay-rich areas. According to the findings, it appears that this plant thrives in light soils.
Rostam Moslempour
Volume 30, Issue 3 , January 2024, , Pages 409-423
Abstract
Background and objectivesIt seems that there is a mutual relationship between the classes of rangeland conditions and the characteristics of vegetation and biodiversity. However, there is relatively little and contradictory information in this regard. This research was conducted to compare the percentage ...
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Background and objectivesIt seems that there is a mutual relationship between the classes of rangeland conditions and the characteristics of vegetation and biodiversity. However, there is relatively little and contradictory information in this regard. This research was conducted to compare the percentage of cover, litter, density, production, and numerical indicators of biodiversity among 11 types of plants in the Darmian-Sarabisheh protected area. MethodologyAfter the field survey and identification of plant types, 11 plant types could be identified in the entire area. Sampling was done by the random-systematic method. For this purpose, three key areas were selected for each plant type, three transects were established in each key area, and 20 plots of 4 square meters were sampled in each transect. In each plot, the percentage of vegetation cover, litter, density, and production was measured. Canopy cover and litter percentage were determined visually. Plant density was calculated by counting plants per unit area. Production was estimated through cover vegetation by double sampling. The Adelaide method was used to estimate shrub production. The range condition was evaluated by the modified four-factor method. Species diversity components, including species richness, evenness, and dominance, were calculated by numerical indices. Also, species abundance distribution models (broken-stick, log-normal, log series, and geometric series) were applied to evaluate plant diversity graphically. The chi-square goodness-of-fit test was used to determine the most accurate fit of species distribution to each statistical model. To compare vegetation characteristics and species diversity components among the 11 studied plant types, one-way analysis of variance (ANOVA) and Duncan's multiple range tests were conducted. ResultsThe results of the analysis of variance showed that between the 11 plant types studied in terms of vegetation characteristics, including the percentage of vegetation cover, litter, plant density, and production, and numerical indices related to species diversity, including species richness, evenness, and dominance, there is a significant difference at the p≤0.01. The mean comparison results showed that the highest vegetation cover percentage belongs to Artemisia aucheri - Stipa barbata (51.23%) in good condition. Acantholimon scorpinus - Cousinia eryngioides and Eryngium bungei- Cousinia eryngioides (46.27% and 40.44%, respectively) in poor condition are in the next. The highest plant density belongs to Artemisia aucheri - Stipa barbata (157 individuals) in good condition, followed by Eryngium bungei- Lactuca orientalis (126 individuals) in poor condition. Astragalus verus- Artemisia aucheri in good condition and Acantholimon scorpinus - Cousinia eryngioides in poor condition have higher species diversity (H¢=2.51 and 2.48, respectively). The species abundance of Eryngium bungei- Cousinia eryngioides and Eryngium bungei- Lactuca orientalis types (in poor condition) follows the log-normal series, which represents stable communities. Also, Astragalus verus- Artemisia aucheri and Artemisia aucheri- Stipa barbata, which are in good condition, follow the log series and the geometric series, which represent unstable and fragile communities. ConclusionRange condition was independent of vegetation cover, production, density, species richness, diversity, evenness, and dominance. Some vegetation types are in poor condition despite high vegetation cover, density, and production. The present study also showed that high species diversity is observed even in the poor-condition class of vegetation types and does not necessarily indicate rangeland stability. Determining ecosystem stability and biodiversity based on species abundance distributions (SADs) is also impossible.
Zahra Soleymani; Hannaneh Mohmmadi Kangarani; Marzieh Rezai; Mahnaz Hosseinzadeh
Volume 28, Issue 4 , November 2021, , Pages 787-803
Abstract
Participatory management in the protection of desert ecosystems is important due to the high sensitivity and fragility of these ecosystems. However, insufficient attention to the position of stakeholders in the social relations network has led to its failure. Therefore, identifying ...
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Participatory management in the protection of desert ecosystems is important due to the high sensitivity and fragility of these ecosystems. However, insufficient attention to the position of stakeholders in the social relations network has led to its failure. Therefore, identifying key actors is significant in the participatory management of the desert ecosystems. This study was conducted to investigate the coherence of the cooperation network and determine the key actors of government stakeholders at both levels of government and public institutions considering the participatory management approach. Information and data were collected through surveying, interviews, and participating meetings with representatives of the organizations and local communities. After identifying 45 beneficiary government institutions, a social network analysis questionnaire was developed and completed by 41 members of the local community and 34 members of the governmental institutions. Then, the prepared data were entered into the Microsoft Excel software and were analyzed using the UCINET6.718 software. Two one-dimensional matrices of organization-organization and people-organization were used to delineate the networks; then, different macro and micro indicators of the network such as density, shear points, degree centrality, and betweenness centrality were calculated to interpret the networks. The results showed that density index in both organization-organization (0.672) and people-organization (0.77) cooperation networks were evaluated more than average. So, it is acceptable. Also, the Department of Environmental Protection of Qeshm city has the highest index of betweenness centrality among 45 identified devices in both cooperation networks. Therefore, more cooperation of the organizations involved in participatory management of natural resources is suggested to protect and develop the mangrove forests to reduce each type of environmental pollution.
Taghi Mirhaji; Morteza Akbarzadeh
Volume 10, Issue 2 , September 2019, , Pages 193-214
Mohsen Shabani; Maryam Azarakhshi; Jalil Farzadmehr; Masoud Bazrafshan
Volume 26, Issue 2 , July 2019, , Pages 423-431
Abstract
The cultivation of plants that are resistant in difficult environmental conditions is an effective solution for reclamation of lands; thus, recognizing the effects of cultivation of different plants on soil and vegetation cover could be a suitable guide to select proper species by ...
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The cultivation of plants that are resistant in difficult environmental conditions is an effective solution for reclamation of lands; thus, recognizing the effects of cultivation of different plants on soil and vegetation cover could be a suitable guide to select proper species by experts. The aim of this research was to investigate the effects of range improvement and reclamation practices on soil and vegetation cover characteristics in Jannat Abad rangeland. For this purpose, four transects of 100-m length and two transects of 100-m length were established with 100-m intervals in the seedling area (Atriplex canescens and Haloxylon aphyllum) and the control area (natural vegetation), respectively. Along each transect, 10 plots of 4m2 were sampled. In each plot, the vegetation data including canopy cover percentage, litter, gravel, bare soil, dominant species, and plant density were measured. Soil profiles were dug at the beginning and end of each transect. Soil sampling was performed from 0-30, 30-60 and 60-90 cm depths. Then, soil chemical and physical properties including electrical conductivity, pH, organic matter, phosphorus, potassium, nitrogen, bulk density, clay, silt, and sand percentage. The collected data were analyzed by independent t-test with SPSS software. Results showed that the cultivation of Atriplex canescens caused an increase in canopy cover percentage, density, and potassium content in the first and second depths (P<0.01), and caused an increase in the nitrogen content of the first depth, organic matter of the second depth, electrical conductivity of the first and second depths, and silt percentage in the first and third depths (P<0.05). It also caused a decrease in soil pH and sand percentage of the second and third depths (P<0.05). The cultivation of Haloxylon aphyllum caused an increase in density, electrical conductivity of the first depth, and a decrease in clay percentage in the third depth (P<0.05), compared to the control area.
Nadia Kamali; ahmad sadeghipour; Alireza Eftekhari
Volume 25, Issue 3 , November 2018, , Pages 686-698
Abstract
This study was conducted to investigate the changes in the soil seed bank of Sisab region due to the pit-seeding operation. To recognize the seed bank potentials, sampling was done using a randomized-systematic method at tow depths of 0-5 and 5-10 cm in winter 2016. Two transects of 500-m length were ...
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This study was conducted to investigate the changes in the soil seed bank of Sisab region due to the pit-seeding operation. To recognize the seed bank potentials, sampling was done using a randomized-systematic method at tow depths of 0-5 and 5-10 cm in winter 2016. Two transects of 500-m length were stablished in the pit-seeding region and in the control area and 10 plots of 1m2 were used along each transect. To study the effects of pit-seeding and soil depth as well as their interaction on the soil seed bank characteristics, a factorial design was applied. In the case that the interaction between pit-seeding and depth was significant, the unpaired T-test was applied to study the seed bank characteristics in each depth of the pit-seeding and control regions. A paired T-test was also used to compare the seed bank characteristics between the two depths. The results showed that pit-seeding had significant effect on soil seed bank characteristics and caused to increased density, diversity, and species richness of seed bank. In addition, all characteristics of the soil seed bank were significantly higher in the top soil. Our results clearly showed that the pit-seeding operation not only increased the forage production in the study area but also increased the diversity and seed density, whose ultimate result could improve the rangeland ecosystem function.
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.
maryam daneshgar; reza Erfanzadeh; hasan qelichnia
Volume 24, Issue 3 , October 2017, , Pages 503-512
Mojtaba Eidi; Ataollah Ebrahimi; Esmaiel Asadi; Hormoz Sohrabi; Hamzehali Shirmardi
Volume 21, Issue 3 , December 2014, , Pages 455-465
Abstract
In this study, the distance methods of density measurementwere compared for four plant species in terms of accuracy, time, and efficiency of the random distribution patterns in Karsanak area, located in the eastern part of Shahrekord in Chaharmahal-va-Bakhtiary province. The study area with 32000m2(160*200) ...
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In this study, the distance methods of density measurementwere compared for four plant species in terms of accuracy, time, and efficiency of the random distribution patterns in Karsanak area, located in the eastern part of Shahrekord in Chaharmahal-va-Bakhtiary province. The study area with 32000m2(160*200) was divided into eight sections of 4000 m2. The total number of each species was counted in each section and considered as the basis for the simulation. Then, eight sections with 4000m2 area were simulated in Stochastic Geometry software, and in each section, a transect of 100m length was established in the center of small side along which 10 points were determined by random systematic method with nine-meter intervals. The distance methods compared included nearest neighbor, closest individual, third closest individual, random pairs, point center quarter, angle order, wandering quarter and variable area transect as well as control group (counting the number of each species in each section). The selected species included Astragalus effuses, Eryngium billardieri, Astragalus rhodosemius and Astragalusverus. The distribution pattern of plant communities was determined by Hopkines and Eberhardt indices. The density estimation error was calculated to evaluate the accuracy. Duncan's test was used to compare the accuracy of methods, and standard deviation and time method were used to compare the efficiency of methods. The results of this study showed that nearest neighbor and closest individual methods (in terms of time), random pairs method (in terms of accuracy) and variable area transect (in terms of precision) could be introduced as the most efficient methods.
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.
Ali beman Mirjalili; Ghasem ali Dianati Tilaki; Naser Baghestani
Volume 15, Issue 3 , January 2008, , Pages 295-303
Abstract
Five distance sampling techniques used to estimate density for Artemisia aucheri and Cornulaca monacantha species in this survey include: point center quarter, closest individual, nearest neighbor, random pairs and angle order methods. Sampling was conducted within 3 (40 m ×100 m) sampling areas ...
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Five distance sampling techniques used to estimate density for Artemisia aucheri and Cornulaca monacantha species in this survey include: point center quarter, closest individual, nearest neighbor, random pairs and angle order methods. Sampling was conducted within 3 (40 m ×100 m) sampling areas selected in TangLaybid. 30 points were selected equidistant apart along 10 randomly located 100-m transects for measurement of distance within each sampling area. Density obtained by each method was compared to the total count in a randomized complete design and Duncan’s test. Hopkines and Eberhardt indices were used to detect dispersion pattern of plants. The point center quarter method provided a reliable estimate of density for Cornulaca monacantha in the community with density of 0.38/ and a clumped distribution. The nearest neighbor method gave a reliable estimate of density for Artemisia aucheri in the communities with density of 1.8/ and 2.9/ and a tendency toward uniformity. Results showed that the point center quarter method can give reliable results in shrub communities with cover around 10% and a clumped pattern while the nearest neighbor method can give a reliable estimate in communities with cover between 16-20% and a uniform pattern.
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.
Hosein Tavakoli; Abbas ali Sanadgol; Uosef Garivani
Volume 13, Issue 2 , February 2006, , Pages 69-73
Abstract
Russian brome (Bromus tomentellus) is a prennial grass with good adaptability to climatic condition of north Khorasan. So, it has promise for using in range improvement projects. Because threre is no enough local information about mangement of this plant, the present experiment has been conducted in ...
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Russian brome (Bromus tomentellus) is a prennial grass with good adaptability to climatic condition of north Khorasan. So, it has promise for using in range improvement projects. Because threre is no enough local information about mangement of this plant, the present experiment has been conducted in Sisab Reaserch Station (SRS) to evaluate the response of this species to grazing intensities and rest grazing. Four grazing intensities of light (20 to 45% of forage removal), moderate (45- 65% of forage removal), heavy (65- 80% of forage removal) and without grazing as control applied by herd of lamb and sheep for three consequent years from 1999 to 2001. The year of 2002 considered as rest period from grazing. Herbage mass and number of plant per unit area measured as an index response. Herbage mass production decreased by reduction in precipitation. Heavy grazing resulted in significant reduction in herbage production and number of plants per unit area, but one year rest from grazing componsated the negative effect of intensive grazing on herbage mass reduction. Management implication based on this results show that plant can tolerate grazing intensity by 45-65% of herbage removal and indicate on the importance of rest grazing on survivance of this plant.
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.