Ali Mohammadian; Esmaiel Asadi borujeni; Ataollah Ebrahimi; Pezhman Tahmasebi; Ali Asghar Naghipour
Volume 27, Issue 1 , April 2020, , Pages 84-97
Abstract
This study was was don to investigate the interaction of fire and grazing effects on index of vegetation diversity in Semi-steppe rangelands in Chaharmahal - Bakhtiari Province.Therefore, 16 sites was selected with different periods of fire and grazing intensity and 18 quadrates along transects ...
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This study was was don to investigate the interaction of fire and grazing effects on index of vegetation diversity in Semi-steppe rangelands in Chaharmahal - Bakhtiari Province.Therefore, 16 sites was selected with different periods of fire and grazing intensity and 18 quadrates along transects at each site were determined and then a systematic -random sampling method was don. Then, species diversity and Beta diversity indices were calculated. To determine the effects of fire, grazing, number of year and their interactions on the diversity indices, the method of General Linear Model (GML) and for determining the significant effect between fire site and unfired site the method of T- Test was used. The results showed that in areas with moderate grazing intensity and with different periods time of fire, Diversity, Simpson, Shannon and species richness indices, compared to control areas significantly increased. But beta diversity has decreased. Simpson's and Shannon Index compared to control areas significantly increased, in areas with high grazing and different time periods of fire, and in areas with 1-3 and 3-5 years fire, Species Richness was increased and decreased respectively. Also with different time periods of fire, beta diversity was decreased. Despite the restoration of some shrub species with the passage of time at burned areas, Compared to control, the grazing intensities was significantly decreased and the highest percentage of perennial grasses coverage was observed in fire areas in places with moderate grazing intensity. After the fire, appropriate management methods in Semi-Steppe Rangelands, can increase the Forage quality and also cause an increase in species richness.
Asad Sadeghpour; Javad Moetamedi; Esmaeil Sheidai Karkaj
Volume 26, Issue 4 , December 2019, , Pages 838-854
Abstract
Information of plant diversity and its relationship with environmental factors are necessary requirements for rangeland rehabilitation techniques and priority of biodiversity conservation in local habitats. To collect vegetation cover data, the Namin mountainous rangelands were selected and systematic ...
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Information of plant diversity and its relationship with environmental factors are necessary requirements for rangeland rehabilitation techniques and priority of biodiversity conservation in local habitats. To collect vegetation cover data, the Namin mountainous rangelands were selected and systematic random sampling in ecological units was used. The relationship between plant diversity and ecological unit’s characteristics (Sub-basins) was studied by recording the data in physiographic, topographic, chemistry and physics in the soil. To investigate the relationship between species diversity and environmental factors, the redundancy analysis (RDA) method was used as linear method based on gradient length. Based on the results, the physiographic and topographic had significant effect on the richness of the species. On the other hand, soil chemical properties had the greatest impact on the amount of species evenness and diversity of the ecological units and explained 89.64% of the variations. In general, slope, organic carbon amd EC are the most important effective characteristic on the enhancement species diversity idexes and the length parameters. It was also indicated that area and direction of sites are the most important factors on reduction of diversity indices. Therefore, in situations where the purpose of the management to be improve species diversity, places where are in endanger in terms of chemical properties of the soil (organic matter and, consequently, organic carbon) should be prioritized. If the aim of management to be increase in vegetation structure and percentage of plant protection from splash erosion, in this case, places where are in the southern direction and have a steep slope should be prioritized. Furthermore, rangeland rehabilitation techniques are a priority in larger-scale units due to the lower species richness, and smaller units, due to the high plant species richness, should be prioritized of conservation and protection.
maryam daneshgar; reza Erfanzadeh; hasan qelichnia
Volume 24, Issue 3 , October 2017, , Pages 503-512
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 ...
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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.
Sajad Amiri; reza erfanzadeh; yahya esmaeil pour; reza omidipour
Volume 23, Issue 3 , January 2017, , Pages 645-660
Abstract
This research was aimed to study the effects of elevation and aspect on diversity components (alpha, beta and gamma) using additive partitioning in the Geno Mountain. All plant species were listed in nine elevation zones (400-1050 m a.s.l.) in southern and eastern aspects of Geno. The cover percentage ...
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This research was aimed to study the effects of elevation and aspect on diversity components (alpha, beta and gamma) using additive partitioning in the Geno Mountain. All plant species were listed in nine elevation zones (400-1050 m a.s.l.) in southern and eastern aspects of Geno. The cover percentage was measured using five plots of 4m2 (in total 90 plots) in each elevation zone. Total plant species diversity (γr) was partitioned into additive components within plots (α1) and between plots (β1) and among elevation zones (β2) and among aspects (β3). The results showed that β3 diversity (72.36%) and β1 (8.19%) had the highest and lowest contribution to the total diversity (γr), respectively. The β3 and α1 values were higher and lower than the expected values, respectively, indicating the non-random distribution of plant species. The lowest observed percentage and expected values at the alpha level were recorded for both southern and eastern directions. In addition, the lowest observed values at the alpha level were recorded for the southern (5.95%) and eastern (5.73%) directions. Generally, beta components had a higher percentage, whose values were higher than that of the expected values. On the other hand, the alpha component in eastern and southern directions was lower than expected values. The results showed that the highest Shannon index (1.72) and richness (22) were obtained at elevations of 1200-1600 m a.s.l. and 1600-2050 m a.s.l, respectively.According to the results of this study, it is suggested that the regional scale (whole area) should be taken into consideration to protect and enhance the diversity.
Razieh Mohammadi; Kamaladdin Naseri; Gholamali Heshmati
Volume 21, Issue 1 , June 2014, , Pages 119-127
Abstract
This study was conducted to investigate the effects of Haloxylon aphyllum plantation on natural plant communities and soil properties of Abbas-Abad area in Khorasan Razavi Province. For this purpose, Haloxylon plantation and control areas were selected to compare with each other. In each area, fifty- ...
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This study was conducted to investigate the effects of Haloxylon aphyllum plantation on natural plant communities and soil properties of Abbas-Abad area in Khorasan Razavi Province. For this purpose, Haloxylon plantation and control areas were selected to compare with each other. In each area, fifty- meter transects were located by random-systematic method. Measurements were done by point sampling method. Eighteen soil samples were collected from Haloxylon plantation and control areas to determine EC and pH values in the laboratory. Data were analyzed by t-test. According to the results, although higher species diversity was significant in Haloxylon plantation area (P<0/05), Haloxylon caused the replacement of non-native communities, so that only 64.28% of species composition in Haloxylon plantation area was similar to the control area. On the other hand, higher soil pH and EC in Haloxylon plantation area was significant (P<0/01) and probably in the long term, Haloxylon causes the salinity and alkalinity of the soil surface.
Naghmeh Gholami; Mansur Mesdaghi
Volume 18, Issue 4 , September 2012, , Pages 515-525
Abstract
In this research, the spatial patterns of shrubs were determined by using T-square distance method in protected and unprotected areas of Golestan National Park. The results indicated that the patterns of shrubs were clumped – regular and clumped – random in woodlands. There were numerous ...
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In this research, the spatial patterns of shrubs were determined by using T-square distance method in protected and unprotected areas of Golestan National Park. The results indicated that the patterns of shrubs were clumped – regular and clumped – random in woodlands. There were numerous species of shrubs in protected area and the canopy cover of grasses and forbs were much higher under the shrubs than that of unprotected area. So the richness and diversity of the species were higher than the unprotected area. The dominant species of unprotected area was Ephedra distachya and the grasses and forbs had less contribution in vegetation of the area. Bare soil and rocks were appeared more frequently.
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 ...
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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
Ali Mohammad Asaadi; Ali reza Dadkhah
Volume 17, Issue 4 , November 2011, , Pages 589-603
Abstract
In this study, floristic composition and species richnessof Pelmiss summer rangeland located between Bojnord and Esfarain were studied through flora collection and using Whittaker plots in exclosure and degraded rangelands. The main goals of this study were to determine floristic composition and species ...
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In this study, floristic composition and species richnessof Pelmiss summer rangeland located between Bojnord and Esfarain were studied through flora collection and using Whittaker plots in exclosure and degraded rangelands. The main goals of this study were to determine floristic composition and species richness in different vegetation types and also effects of slope and aspect on species richness. The data were analyzed by using linear and group regression model. According to the results, two relationships i.e. (HE > CH > TH > GE >PH) and (Forbs > Woody plant > Grasses) were found in view of biological types and growth form respectively. Species richness in exclosure area was more than that in degraded area. Species richness in western and northern slopes was also higher than that in eastern and southern slopes. In general, it can be concluded that vegetation of the study area is mostly of perennial plant species, a characteristic of mountainous areas with cold climate in altitudes.
Esfandiar Jahantab; Adel Sepehri; Bahareh Hanafi; Zohreh Mirdeilamy
Volume 17, Issue 2 , September 2010, , Pages 292-300
Abstract
The study of plant diversity dynamic on grazed and enclosed rangelands is important in range management. The effect of enclosure was studied on plants diversity dynamics on two range condition sites of Dishmook area in Kohgiluyeh & Buyer Ahmad province. Random-systematic sampling was done in two ...
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The study of plant diversity dynamic on grazed and enclosed rangelands is important in range management. The effect of enclosure was studied on plants diversity dynamics on two range condition sites of Dishmook area in Kohgiluyeh & Buyer Ahmad province. Random-systematic sampling was done in two range sites using 220 (2×2 m2) quadrates along 6 transects with the length of 100 m. Vegetation canopy cover percentage was recorded simultaneously in both range sites. Diversity, richness and evenness were determined by using plant diversity indices (Shannon, Simpson, Berger parker & Mc intash). Results show a higher species richness, evenness and species diversity indices in enclosed rangeland. Statistical T-Student Test showed significant differences between two sites in 5 percent level of probability.
Zainab Jafarian jelodar; Hosein Arzani
Volume 16, Issue 3 , December 2009, , Pages 317-328
Abstract
Plant species have important role in other organisms life circle. High diversity of plant species cause equilibrium and stability of this circle, so conservation of plant species is essential for continuity and survival of ecosystems. In this study vegetation species diversity and flora in four sub watersheds ...
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Plant species have important role in other organisms life circle. High diversity of plant species cause equilibrium and stability of this circle, so conservation of plant species is essential for continuity and survival of ecosystems. In this study vegetation species diversity and flora in four sub watersheds of Armoot, Kash, Zidasht and kalanak in Taleghan region with 16320 hectares area were studied. Thirteen vegetation types were recognized in the study area. One key area was selected in each vegetation types (in some of the vegetation types because of vast area and non –homogeneity vegetation, two key areas were selected). Two 100 meter transects were located in each key area, along each transect, 10, one meter square quadrates were located. List of species and number of species were recorded for each quadrates. Then diversity indices, species richness and evenness indices were calculated. Simpson diversity index and Shanon– Wiener diversity index were obtained 0.114 and 2.81 respectively which indicate relatively high species diversity in the study area. Species evenness based on studied indices was estimated. Richness of species was 116 with 18 families and 63 genus in rangelands of the study area.