Ali Asghar Naghipour Borj; Sina Nabizadeh; Javad Pourezaie
Volume 26, Issue 3 , September 2019, , Pages 587-598
Abstract
Fire is one of the most important influencing factors on the structure and composition of plant communities, especially in arid and semiarid rangelands. This study was designed to investigate the role of fire on vegetation dynamics in semi-steppe rangelands of Central Zagros. ...
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Fire is one of the most important influencing factors on the structure and composition of plant communities, especially in arid and semiarid rangelands. This study was designed to investigate the role of fire on vegetation dynamics in semi-steppe rangelands of Central Zagros. A stratified random sampling was used to collect the data from six sites with one and five years after the last fire. At each rangeland site, 20 plots with four square area meters, 10 plots in the burned sites and 10 plots in the control sites, were used. The cover percentage of each species was accurately recorded. A one-way analysis of variance and Tukey's test were used to compare each of the variables. The results showed that the fire significantly reduced the vegetation cover and litter, and increased the bare soil surface in the region. The composition of the fire region was close to the control area after a period of five years. The fire caused a decrease in the percentage of shrubs and an increase in the proportion of perennial grasses, annual grasses, and annual forbs in the region. The fire also changed the vegetation composition of rangelands, so that the proportion of hemicryptophytes, therophytes, and geophytes were decreased while chamaephytes increased. Fire also increased the proportion of high and moderate palatable species (class I and II) and reduced the proportion of class III species. Based on the results of this study, it can be concluded that the fire reduces litter and increases the bare soil; consequently, the soil erosion is exacerbated, hence this should be considered in rangeland management. Overall, uncontrolled fires in the semi-arid regions of the country will not lead to the restoration of vegetation cover.
ali goharnejad; pejman tahmasebi; esmael asadi; javad motamedi
Volume 24, Issue 1 , May 2017, , Pages 1-15
Abstract
In contrast to the taxonomic biodiversity, based only on the relative abundance of species in the community, functional diversity summarizes various aspects of the biological composition and, hence, the role of populations in the community. Functional diversity may be linked directly to the ecosystem ...
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In contrast to the taxonomic biodiversity, based only on the relative abundance of species in the community, functional diversity summarizes various aspects of the biological composition and, hence, the role of populations in the community. Functional diversity may be linked directly to the ecosystem services; the plant biomass encompasses many ecosystem services such as food supply, conservation, tourism, and pollination. In this study, we tested several hypotheses (1) existence of a close relationship between species richness and plant biomass (2) existence of a close relationship between FAD2 (Functional Diversity index) and plant biomass (3) explaining the high percentage of plant biomass variations. The results showed that the species richness in order to predict the plant biomass with a correlation coefficient equal to three does not count as a proper indicator. However, the correlation coefficient of FAD2 Functional Diversity with plant biomass was about 0.4, which is relatively good indicator to estimate the plant biomass because of explaining a significant percentage of the biomass variations. Finally, our results clearly showed that the incorporation of abiotic factors, plant traits and functional diversity (FAD2), containing the parameters of rainfall, leaf length, plant height and FAD2 index, could explain 75% of plant biomass variations and was considered as the most appropriate model predicts plant biomass.
Esfandiar Jahantab; Yaser Ghasemi Aryan; Adel Sepehri; Bahareh Hanafi; Enayat allah Yazdan panah
Volume 19, Issue 3 , December 2012, , Pages 482-489
Abstract
Knowledge of the plant distribution pattern in each region is of principles and fundamentals of vegetation survey and measurement that plays an important role in the selection of management approaches. A study was performed to determine the distribution pattern of three dominant species of Artemisi aaucheri, ...
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Knowledge of the plant distribution pattern in each region is of principles and fundamentals of vegetation survey and measurement that plays an important role in the selection of management approaches. A study was performed to determine the distribution pattern of three dominant species of Artemisi aaucheri, Kelussiao doratissima and Prangos ferulaceae in Dyshmuk region in northwestern Kohgilouyeh and Boyer Ahmad province. One hundred quadrates of 2×2 m were randomly located along six transects of 100-m length and the number of each species was recorded. Using this information, the most appropriate and accurate quadrate-based distribution indices (Green and standard Morisitat indices) were calculated. According to the results, Kelussia odoratissima and Prangos ferulaceae showed a random distribution pattern while distribution pattern of Artemisia aucheri was uniform to random.
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.