Relationship Between Environmental Factors and Plant Distribution in Arid and Semiarid Area (Case Study: Shahriyar Rangelands, Iran) (original) (raw)
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Analele Universitatii din …
A major scientific challenge in plant ecology is to identify and quantify the strength of environmental factors that are responsible for the distribution and abundance of plant species within and among ecosystems. Hence, this study is focused on relation between plant communities and environmental variables in Khezrabad region of Iran. Based on field surveys, eight vegetation types including Artemisia sieberi-Acantholimon erinaceum, Artemisia sieberi-Hertia angustifolia, Artemisia sieberi-Launea acanthodes, Artemisia sieberi-Salsola tomentosa, Artemisia sieberi-Zygophyllum atriplicoides, Artemisia aucheri-Astrgalus albispinus, Artemisia sieberi-Fortuynia bungei, Haloxylon aphyllum were identified. With respecting to the present variance between vegetation and environmental factors, four samples were established in each vegetation type in 0-30 cm depth. The studied soil variables affecting plant communities were texture, EC, pH, Na + , k + , Cl -, Ca 2+ , Mg 2+ , SP, O.M, CaCO3, HCO3and CEC. Among the topographic conditions, elevation was recorded in sampling regions as well. Data matrix of environmental factors and vegetation type was made using the windows (ver. 4.17) of PC-ORD. Results according to PCA showed that in the study area, among different environmental factors, the distribution of vegetation types was most strongly correlated with some agents such as soil texture, salinity and sodicity. In fact, soil texture controls distribution of plant species by affecting moisture availability, ventilation and distribution of plant roots. Beside, soil salinity and sodicity because of habitat condition, plant ecological needs and tolerance range can have negative affect on plant diversity. In addition, results indicated that increasing of elevation had negative effect on plant distribution. However, soil characteristics have more influence on vegetation separation than to the elevation in this study.
Soil-Vegetation Relationships in Hoz-e-Soltan Region of Qom Province, Iran
Pakistan Journal of Nutrition, 2003
The objective of this study was to find the effective soil variables on the distribution of vegetation types in Hoz-e-Soltan region. Study area was located in the saline region of Qom province. After delimitation the study area and determining plant types, sampling of soil and vegetation were done by randomizedsystematic method. The area of quadrants was identified according to the minimal area procedure and the kind of plants distribution. Among vegetation properties, cover percentage and density were estimated quantitatively. Soil was sampled at 0-20 and 20-60 cm depths. Measured soil factors included texture, electrical conductivity (EC), acidity (pH), lime, soluble ions such as Ca , Mg , Na , K , Cl , CO and HCO. 2+ 2+ + +-2-3 3 In order to find the relationship between soil factors and vegetation properties and also to determine the most effective factors on the distribution of plant types, multivariate procedures, i.e., principal component analysis (PCA) and canonical correspondence analysis (CCA) were used. Results showed that there was a specific relationship between soil variables and plant types. The most effective factors on the separation of different communities were soil salinity and texture.
Journal of Arid Environments, 2004
The objective of this research was to study the relationships between environmental factors and vegetation in order to find the most effective factors in the separation of the vegetation types in Poshtkou rangelands of Yazd province. Sampling of soil and vegetation were performed with randomized-systematic method. Vegetation data including density and cover percentage were estimated quantitatively within each quadrat, and using the two-way indicator species analysis (TWINSPAN), and vegetation was classified into different groups. The topographic conditions were recorded in quadrat locations. Soil samples were taken in 0-30 and 30-60 cm depths in each quadrat. The measured soil variables included texture, lime, saturation moisture, gypsum, acidity (pH), electrical conductivity, sodium absorption ratio, and soluble ions (Na + , K + , Mg 2+ , Cl À , CO 3 2À , HCO 3 À and SO 4 2À). Multivariate techniques including principal component analysis (PCA) and canonical correspondence analysis (CCA) were used to analyse the collected data. The results showed that the vegetation distribution pattern was mainly related to soil characteristics such as salinity, texture, soluble potassium, gypsum, and lime. Totally, considering the habitat conditions, ecological needs and tolerance range each plant species has a significant relation with soil properties.
Distribution of Vegetation Type according to Edaphic Properties and Topography in Iran
Polish Journal of Environmental Studies
The current research was carried out to find the most effective environmental factors in plant species distribution. For this purpose, a study was conducted in the Taleghan rangelands of Tehran province. Based on a vegetation map and field surveys, indicator vegetation types were identified. Within each type, 3 parallel transects with 150 m length, each containing 15 quadrates (according to vegetation variations) were established. The sampling method was randomized systematic. Quadrat size was determined for each vegetation type using the minimal area method. The floristic list and canopy cover percentage were determined in each quadrat. The topographic conditions (elevation from sea, aspect, and slope) were recorded in quadrat locations. Soil samples were taken from 0-30 cm in starting and ending points of each transect. Measured soil properties included depth, texture, organic matter, lime, pH, electrical conductivity, nitrogen, and potassium. To determine the most environmentally effective factors on plant distribution, multivariate techniques, including the principal component analysis (PCA) and canonical correspondence analysis (CCA) methods were applied. The results indicated that edaphically factors such as texture, potassium, and organic matter play a main role in the distribution of plant species.
Soil-Vegetation Relationships In Arid Rangelands (Case Study: Nodushan Rangelands Of Yazd, Iran)
2012
The objective of this research was to identify the vegetation-soil relationships in Nodushan arid rangelands of Yazd. 5 sites were selected for measuring the cover of plant species and soil attributes. Soil samples were taken in 0-10 and 10-80 cm layers. The species studied were Salsola tomentosa, Salsola arbuscula, Peganum harmala, Zygophylum eurypterum and Eurotia ceratoides. Canonical correspondence analysis (CCA) was used to analyze the data. Based on the CCA results, 74.9 % of vegetation-soil variation was explained by axis 1-3. Axis 1, 2 and 3 accounted for 27.2%, 24.9 % and 22.8% of variance respectively. Correlation between axis 1, 2, 3 and speciesedaphic variables were 0.995, 0.989, 0.981 respectively. Soil texture, lime, salinity and organic matter significantly influenced the distribution of these plant species. Determination of soil-vegetation relationships will be useful for managing and improving rangelands in arid and semi arid environments.
Grassland Science, 2000
To investigate the cause of differences among ecological plant groups in the east of the Elborz mountain rangeland, the role of edaphical and topographical characteristics was considered. Two ordination techniques, detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA), were used. The values of slope, aspect, altitude and lithology information were provided by Geographic Information System (GIS), and geomorphological land units were determined by intersection of overlaid data layers. Plant sampling was undertaken within nine land units with similar lithology and altitude but which differed in slope and aspect, using 30 randomly selected 1 m 2 plots per land unit. Soil samples were taken from two depths (0-20 and 20-50 cm) in each plot. Organic matter, bulk density, texture, calcium carbonate, total nitrogen and available phosphorus and potassium contents were determined. The results indicated that plant species have different responses to edaphical and topographical parameters. The invader species group had a balanced amount of influence from all soil components and topographic factors, whereas the native grasses were located in productive soils, which typically have a low grazing intensity, such as the north facing slopes. Coniferous bushy trees, cushion plants and some shrub plant groups were found on steep slopes with alkaline soils. The broad-leaved bushy trees plant group was abundant in fine texture soils on low and humid slopes.
Journal of Environmental Science and Management, 2017
The necessary recommendations for environmental management can be provided by measuring diversity and distribution of plant species. The relationship between species diversity and environmental variables affecting Furg rangelands, in the East of Iran was examined. A systematic-random approach was employed to sample vegetation and soil characteristics. Vegetation sampling was conducted using a 10×10 m quadrate (10 quadrate per vegetation type). According to the rooting depth of plants, soil samples were taken from 0-30 cm depth and analyzed through standard laboratory approaches to determine physical and chemical properties. Species diversity was measured using the indices Simpson, Shannon-Wiener and Fisher's alpha. To determine factors affecting species diversity, the Canonical Corresponding Analysis (CCA) and Principal Component Analysis (PCA) were utilized. The vegetation type Ar.au-Ac.sp (type III) had the highest diversity, which was mainly located on the soils with higher quantities of EC, Ca, Na, Gypsum and sand content. The vegetation type Ar.au-La.or-Co.er (type I) with the lowest diversity was mainly placed on the soils where sand content was higher and soil pH, moisture content, TNV, silt content and slope were lower, as compared with those in other vegetation types. Generally, it could be established that in the studied region, the species diversity of plants was more impacted by soil properties, as compared with topographic characteristics.
A hybrid algorithm specifically designed to work with optimised support vector machine with genetic algorithm (GA-SVM) was developed for determining the relationships between soil properties and plant distribution and vegetation cover densities in a protected area (Ghomeshlu, central Iran). The bulk density, porosity, silt, total nitrogen and chloride contents are the main essential factors (with a screen accuracy of 100%) for the establishment and growth of Scariola. For Astragalus, surface fragment content has the greatest influence, while available phosphorus was screened by the GA-SVM analysis as the factor with a closer relationship with Anabasis growth in the study sites. Particle density, aggregate stability, available magnesium and pH are the more important combination of soil properties affecting the coverage density of Stipa. Soil organic matter content, available phosphorus, total nitrogen, electrical conductivity, porosity and particle density have a closer relationship ...
Impact of Land Use Changes on Soil and Vegetation Characteristics in Fereydan, Iran
Agriculture
To understand and manage ecosystem complexity, it is important to determine the relationships between soil characteristics, human activities, and biodiversity. This study analyzes the relationships between vegetation, soil, and man-made damage with regards to land use change in the Fereydan region, Iran. Soil physical properties such as sand and silt content, clay, saturated soil’s moisture content, and gravel percentage as well as chemical properties such as lime content, pH, electro conductivity (EC), and organic matter content were measured. In order to trace these variables, the principle component analysis (PCA) was applied. The study area was divided into three states of conditions; i.e., good condition rangelands, poor condition rangelands, and abandoned rain-fed area. Based on the results there was a significant difference between species diversity in good condition rangelands compared with two other sites. The results further revealed that among soil chemical and physical c...
Journal of Rangeland Science, 2016
Plant diversity and vegetation distribution in an area are related to the soil physical and chemical properties. The knowledge of relationships between species diversityand soil parameteris essential for sustainable ecosystem management. This study was conducted to investigate the relationships between soil factors and species diversity indices in the protected rangelands of Lashgardar, Malayer, Iran in 2013. The land units in the area were selected in terms of slope, aspect and elevation. Two 100 m length transects were established on the slopes perpendicular to each other with the ten 2 m2 plots on each transect. The diversity, richness and evenness indices were estimated in each plot based on canopy cover percent. Soil samples were taken from each plot in two depths (0-10 cm and 10-30 cm). Then, soil physico-chemical characteristics were measured in the soil laboratory for moisture, texture, Organic Carbon (OC), Organic Matter (OM), CaCo3, bulk density, pH, and EC. The relationsh...