Mahnaz Amini; Hosein Bashari; Mohammad Taghi Feizi
Volume 31, Issue 2 , August 2024, , Pages 129-148
Abstract
Background and objectivesVarious environmental and managerial stresses are severely threatening wetland ecosystems in Iran. The Gavkhouni Wetland, one of the largest and most strategically significant wetlands in the central plateau of Iran, faces numerous challenges. Given its unique ecological importance ...
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Background and objectivesVarious environmental and managerial stresses are severely threatening wetland ecosystems in Iran. The Gavkhouni Wetland, one of the largest and most strategically significant wetlands in the central plateau of Iran, faces numerous challenges. Given its unique ecological importance and the diverse plant habitats surrounding it, studying the vegetation in this area is crucial. Understanding the various conditions of the plants, including dominant families, geographical distribution, biological forms, and conservation status, is essential for any conservation, management, or ecological research activities in this region. MethodologyThe study area encompasses the upper reaches of the Zayandehrud River in Isfahan Province, covering 50,000 hectares with elevations ranging from 1,470 to 2,533 meters above sea level. This region has an arid climate characterized by saline soils, including solonchaks, marshy areas, and sandy soils. The average annual temperature at Gavkhuni Wetland is 17.6 degrees Celsius, with total annual precipitation measuring 91 millimeters. According to the Ambrothermic curve, the area experiences a prolonged dry period from April to November. Field surveys were conducted using 1:25,000 scale topographic maps from early October to November 2021. During these surveys, plant samples were collected, pressed, dried, and identified at the herbarium of the Natural Resources Department of Isfahan University of Technology, with consultation from experts and reliable scientific sources. This research resulted in a comprehensive list of plant species, detailing their scientific names, families, genera, life forms, geographical distribution, and conservation statuses. ResultsThe study identified 100 plant species from 16 families and 65 genera in the region, with 27 species possessing medicinal and industrial properties. The Amaranthaceae family, with 31 species, and the Asteraceae family, with 14 species, collectively constitute 45% of the vegetation cover. Other prominent families include Poaceae with 10 species and Fabaceae with 9 species. In terms of life forms, therophytes dominate at 40%, followed by hemicryptophytes at 23%. Geographically, 71% of the identified species belong to the Irano-Turanian floristic region. Despite the ecological challenges faced by the area, its diverse topography and edaphic factors have fostered significant species diversity. ConclusionGavkhuni Wetland's flora is highly sensitive to climate and management practices. Despite facing severe biological constraints, the region exhibits relatively robust plant diversity. Inadequate management of the Zayandehrud watershed, particularly in Gavkhuni Wetland, has resulted in declining groundwater levels and increased aridity, threatening many plant species with drying, pest infestations, shrub encroachment, and overgrazing. Continued adverse conditions, exacerbated by climate change, pose a significant threat to the region's flora.
Parvaneh Ashouri; Behnam Hamzeh; Adel Jalili
Volume 27, Issue 3 , October 2020, , Pages 385-395
Abstract
The ecological model of productivity-species richness relationships states that maximum species diversity occurs when species production is moderate, and there is a humped-back pattern between production as ecosystem energy variable and species richness. The discovery of this ...
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The ecological model of productivity-species richness relationships states that maximum species diversity occurs when species production is moderate, and there is a humped-back pattern between production as ecosystem energy variable and species richness. The discovery of this relationship leads to an understanding of the processes of biodiversity formation in ecosystems. To test this model, species production and richness were measured in the semi-steppe ecosystem of Gharebough in the Anguaran wildlife refuge in Zanjan province. Correlation and linear and nonlinear regression analysis were used to examine the relationship between species richness as a dependent variable and productivity as an independent variable. A total of 41 plant species were identified in 30 plots. The average species richness per plot per square meter was calculated as nine species. The relative production percentages were 15% for shrubs, 16% for forbs, and 69% for grasses. The highest percentage of presence in the plots was allocated to Stipa lessingiana, Poa bulbosa, Astragalus stevenianus, and Bromus tomentellus. The total production of the species was calculated to be 83 g/m2. Shrub production and forbs showed a significant linear regression relationship with species richness. Also, the shrub production had a significant nonlinear regression relationship with species richness, showing a humped-back pattern. The findings of this study showed that increasing production increases species richness and according to the values of the coefficient of explanation of regression relations (R2), in addition to the production factor, other important factors play a role in species richness. Therefore, this hypothesis cannot be confirmed on a local scale.
Rahman Adabi Firozjaii; Jamshid Ghorbani; seyd hasan Zali
Volume 27, Issue 1 , April 2020, , Pages 112-124
Abstract
Invasive species are the major threats to natural ecosystems worldwide. Pteridium aquilinum has the widest distribution of any pteridophyta in the world. This study aimed at investigating the impact of Pteridium aquilinum invasion on species composition, richness and diversity, and forage production ...
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Invasive species are the major threats to natural ecosystems worldwide. Pteridium aquilinum has the widest distribution of any pteridophyta in the world. This study aimed at investigating the impact of Pteridium aquilinum invasion on species composition, richness and diversity, and forage production in summer rangelands of Bandpay Babol, Mazandaran province, Iran. Vegetation was sampled in four invaded vegetation types including Fagus orientalist forest, Crataegus shrubland, Crataegus+Berberis shrubland, and rangeland. Also, vegetation sampling was done in surrounding uninvaded rangelands. The cover of species was estimated in 1 m2 plot for herbaceous and 25 m2 for shrubs. In all plots, the cover of P. aquilinum was estimated and then all fronds were cut at ground level, counted and frond length was measured. The forage of palatable species was measured by clipping and weighing. Findings showed different species composition among invaded and uninvaded areas. A total of 25 species were found only in invaded areas whereas only 11 species were detected in surrounding uninvaded rangelands. Cover, density and height of P. aquilinum fronds significantly influenced the species composition. Annuals significantly decreased by Pteridium aquilinum invasion. Except for Crataegus+Berberis shrubland, in other invaded areas the forage production was not significantly different from that in surrounding uninvaded rangeland. There was a reduction of desirable rangeland species due to P. aquilinum invasion. Also, we found that species richness significantly increased when invaded by Pteridium, while the diversity significantly decreased. The current understory floristic composition showed a low potential to support future restoration after P. aquilinum control. This result emphasizes the need for adding the seeds of desirable species
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.
Hamidreza Fallahi; Parviz Rezvani Moghaddam; Mehdi Nassiri Mahallati; Mohammad Ali Behdani
Volume 21, Issue 1 , June 2014, , Pages 62-74
Abstract
In this study, the effects of reconstruction and conservation were investigated on plant diversity of the region of the international Carbon Sequestration Project in Hussein-Abad, South Khorasan province. In the study area, four vegetation types including Haloxylon persicum, Atriplex conescens, Haloxylon ...
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In this study, the effects of reconstruction and conservation were investigated on plant diversity of the region of the international Carbon Sequestration Project in Hussein-Abad, South Khorasan province. In the study area, four vegetation types including Haloxylon persicum, Atriplex conescens, Haloxylon persicum + Atriplex conescens and Zygophyllum eurypterum were planted in 2004. Six years after that, the plant diversity indices of four replanted vegetation types along with control vegetation type (no replanting and conservation programs) was studied in two different dates (April and May) in 2011. For this purpose, 51 quadrates (2 × 2 m) were used in each vegetation type. Results showed that the maximum plant diversity and vegetation coverage were observed in Haloxylon persicum + Atriplex conescens (30 species and 22.5%, respectively) vegetation types, and the minimum values of these indices were recorded in control (20 species and 5.5%, respectively) vegetation type. The highest and the lowest values of plant density were obtained in Atriplex conescens (539,000 plant. ha-1) and control (179000 plant. ha-1) vegetation types, respectively. The Margalef’s richness index was higher in all protected vegetation types, while uniformity index and Shannon diversity index were higher in the control vegetation type. The frequency of 65% of plant species was less than 20% and about 45% of the plant species belonged to therophytes. Overall, the experimental results showed that desert ecosystems could play an important role to improve global biodiversity if proper management programs are employed.
Reza Tamartash
Volume 19, Issue 2 , September 2012, , Pages 221-232
Abstract
With attention to importance of range condition for correct management of range ecosystems and relationship among biodiversity, canopy cover percentage and the importance degree of dominant species with range condition and health, this research was conducted with comparison of three methods including ...
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With attention to importance of range condition for correct management of range ecosystems and relationship among biodiversity, canopy cover percentage and the importance degree of dominant species with range condition and health, this research was conducted with comparison of three methods including pastoral value, six factors and four factors methods in summer rangelands of Lasem, Haraz. Plant types was separated with use of aerial photos (1:20000) and field control on topographic maps (1:50000).The sampling was done by quadrat and transects using random-systematic method in key areas. In this points Shanon, Sympson indices, importance degree of dominant species, canopy cover percent and scores of range condition methods has calculated for determination of relation among them. In order to Pearson correlation test, liner regression and analysis of variance were run with Mini tab 13.3. The results showed that Shanon diversity index had significant relation with six factors, four factors and pastoral value but rate of this relationship to six factors was more than other methods. Sympson index had not correlation with them. The comparison of canopy cover index and importance degree showed that these factors had not significant relation to pastoral value and four factors methods while six factors method had high correlation with them. Thus in this research, the best suitable method of range condition is recognized six factors method.
Maryam Nikan; Hamid Ejtehadi; Mohammad Jangju; Farshid Memariani; Hajar Hasanpour; Fariba Noadoost
Volume 19, Issue 2 , September 2012, , Pages 306-320
Abstract
Livestock grazing is one of the most influencing factors on the rangeland community structure and composition, which can also change the vegetation diversity. The main aim of this research was to survey the flora and plant biodiversity at three rangeland sites, being used under different grazing intensities, ...
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Livestock grazing is one of the most influencing factors on the rangeland community structure and composition, which can also change the vegetation diversity. The main aim of this research was to survey the flora and plant biodiversity at three rangeland sites, being used under different grazing intensities, Baharkish, Quchan, Iran. Three sites were systematically selected along a spatial gradient of low, moderate and high grazing intensity, and 20 quadrates were randomly established within each site. Species composition, abundance and canopy cover were recorded within the quadrates. Simpson and Shannon diversity and Carmago and Smith & Wilson evenness indices were measured for each site. Floristic studies led to the identification of 156 plant species belonging to 34 families. The floristic composition of the area was strongly dominated by the Irano-Touranian elements. Shannon and Simpson diversity indices were significantly higher under the moderate than the low and heavy grazing intensity sites and the lowest diversity was significantly recorded for the heavy grazing site. Evenness indices did not significantly differ between the low and moderate grazing sites, but it was significantly lower under the high grazing site. In conclusion, proper livestock grazing is necessary for preservation of species diversity in the semiarid rangelands; Moderate grazing maintained the species diversity while light and sever grazing reduced or even eliminated some sensitive plant species.