Kambiz Tavakoli; Parviz Karami; Hamed Joneidi Jafari; Bahram Gholinejad bodag
Volume 31, Issue 2 , August 2024, , Pages 186-203
Abstract
Background and ObjectiveFire is a significant ecological factor that influences rangeland ecosystems, particularly in arid and semi-arid regions, where it plays a crucial role in the growth, development, and evolution of plant species. Historically, controlled burning of vegetation in natural ecosystems ...
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Background and ObjectiveFire is a significant ecological factor that influences rangeland ecosystems, particularly in arid and semi-arid regions, where it plays a crucial role in the growth, development, and evolution of plant species. Historically, controlled burning of vegetation in natural ecosystems has been one of the simplest methods for altering and enhancing habitats, as well as for eliminating pests, diseases, and undesirable plants, while also modifying vegetation cover. Understanding the effects of fire on the characteristics of rangeland vegetation is essential for effective post-fire management. Therefore, this study aims to investigate the impact of fire on specific vegetation characteristics and to analyze vegetation responses to fire, with the goal of improving the management of the Sanandaj rangelands. MethodologyFor this study, three areas Khalichian, Hasanabad, and Haft Asiab located around Sanandaj and affected by fires one to three years prior were selected. Following field surveys and sampling, the flora of these areas was identified using available resources. Vegetation types were determined through the physiognomic-floristic method. Six sites were established for vegetation sampling, comprising three burned sites and three control sites. Each pair of burned and control sites was matched based on topographic conditions, including elevation, slope percentage, and slope direction, to minimize the effects of environmental gradients and focus on the impact of fire. In each site, two transects (one along the slope and one perpendicular to it) were established, with 15 plots along each transect, resulting in a total of 12 transects and 180 plots. Within each plot, vegetation characteristics such as the percentage of canopy cover of plant species, bare soil, stones and gravel, and litter were estimated. The Shannon-Wiener index was utilized to calculate diversity and evenness, while the Margalef index was used to assess richness. An independent t-test was conducted to compare the mean vegetation characteristics. ResultsThe results revealed a significant decrease in the canopy cover of shrubs in the burned sites, accompanied by notable increases in the cover of grasses and both annual and perennial forb plants. Total canopy cover, bare soil percentage, production, and species richness significantly increased in all three areas as a result of fire, while litter significantly decreased. Total rangeland production in the fire-affected sites was significantly higher than in the control sites (P < 0.01), with increases of 26.48%, 26.48%, and 40.14% observed in Khalichian, Hasanabad, and Haft-Asiab, respectively. The difference in the species diversity index (Shannon-Wiener index) was not significant in Khalichian; however, it showed a significant increase in the other areas. Comparisons of the Margalef species richness index indicated that fire enhanced species richness in all three areas, with increases reaching significance at the 1% level. The species evenness index exhibited a significant increase in Hasanabad and Haft-Asiab, but not in Khalichian. An examination of plant composition in the studied areas indicated that fire reduced the prevalence of woody species while promoting an increase in herbaceous plants. ConclusionThis study concluded that fire generally results in an increase in live vegetation cover, a reduction in litter, and an increase in bare soil. Additionally, fire alters plant composition, favoring herbaceous plants over woody species. Therefore, it is recommended that controlled burning be implemented in grasslands where plant composition has shifted and woody species have proliferated. Such practices should be considered alongside other economic, social, and environmental factors to enhance rangeland conditions.
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.
Alireza Eftekhari; Mahmoud Goudarzi; Parvaneh Ashouri; Rostam Khalifehzadeh
Volume 26, Issue 2 , July 2019, , Pages 352-366
Abstract
Fire in rangelands has significant effects on plant and soil factors. In this research, the effects of fire on plant factors were investigated in semi-steppe rangelands of Sirachal for three years (2015-2017). The two selected rangelands were similar in terms of vegetation type (before ...
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Fire in rangelands has significant effects on plant and soil factors. In this research, the effects of fire on plant factors were investigated in semi-steppe rangelands of Sirachal for three years (2015-2017). The two selected rangelands were similar in terms of vegetation type (before the fire) were next to each other. The treatments included control rangelands and burned rangelands, and sampling was performed using transects and quadrates (30 plots) for three consecutive years. Vegetation factors included canopy cover, production, density, species richness, and life form. The statistical analysis of the treatments was carried out using the independent t-test. Comparison of different years, in each of the burned or control rangelands, was done using analysis of variance and the means were compared with Duncan's test. The results showed that fire during the years of the project did not have a significant effect on the canopy percentage and the production of all rangeland species, but it had a positive and significant effect on the density of all rangeland species. High difference in density compared to the cover and production could be due to the low canopy cover and production of new seedlings. In other words, new seedlings of plants had a low canopy cover, low production, and a high density. In terms of species richness, the highest difference is related to the absence of shrub species in the burned rangeland; however, according to the Sorenson index, the two treatments were similar in terms of plant species. Also, in terms of life form, fire had a positive and significant effect on the cover percentage, density and production of forbs, a positive and significant effect on the cover percentage and density of grasses, and a significant negative effect on the shrubs.
Hosein Behzadi; Saeed Mohtashamnia; Hosein Gharedaghi
Volume 25, Issue 4 , February 2019, , Pages 817-828
Abstract
Bamu National Park, has witnessed an annual fire and its repetition for many years. Considering the importance of preserving the park and its proximity to Shiraz refinery, fire hazard zoning was conducted using geographical information system (GIS) and Analytic hierarchy process (AHP). With regards to ...
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Bamu National Park, has witnessed an annual fire and its repetition for many years. Considering the importance of preserving the park and its proximity to Shiraz refinery, fire hazard zoning was conducted using geographical information system (GIS) and Analytic hierarchy process (AHP). With regards to the four factors of physiography (elevation, slope, direction), climate (temperature and precipitation), human factors (tourism, industrial areas, military regions, residential areas and roads) and fuels (vegetation type and density) and weighting according to digital layers, expert opinions, questionnaire filling and integration of manufacturing layers, the final mapping of fire zoning classified into 0-20 (no risk), 20-40 (low risk), 40-60 (medium risk), 60-80 (risky) and 80-100 (high risk). The results showed that 23.3% (14263 hectares) and 20.25% (2.84) of the area were located in the dangerous and very dangerous zones, respectively. Evaluating the provided model accuracy showed that 76.60% of the previously fired areas located in dangerous and very dangerous zones, and this subject shows the adaptation of the reality with the prepared maps. With a logical connection between the risk areas and the real places, the success of this method can be proved. So, it is suggested to develop a particular crisis management plan and increase the equipments and human resources for preventing fire and its spread in dangerous and very dangerous zones.
Khadije Bahalkeh; Mehdi Abedi; Ghasemali Dianati Tilaki
Volume 25, Issue 1 , April 2018, , Pages 140-151
Abstract
The presence of plant species together causes biotic interactions. These interactions are very complex and variable among species which facilitation and competition have the highest impact on ecosystem function. Disturbances including fire are among the environmental factors affecting the biotic interactions. ...
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The presence of plant species together causes biotic interactions. These interactions are very complex and variable among species which facilitation and competition have the highest impact on ecosystem function. Disturbances including fire are among the environmental factors affecting the biotic interactions. This study aimed on understanding the effect of fire on biotic interactions of cushions and grassland species. Therefore, to survey the effects of fire on the biotic interaction, 30 individuals of non burned Onobrychis cornuta and also 30 individuals of burnt patches were selected. In addition, 30 paired plots for each individual was randomly established close to each patches. According to our results, the effect of fire was not significant on total cover, but fire increased the perennial forbs (from 4.7 to 11.3 %), geophytes (from 0.1 to 0.5 %), annual forbs (from 0.1 to 2.3 %), annual grasses (from 0 to 0.1 %) and also decreased the perennial grasses (from 7.2 to 4.9 %), shrubs (from 3.8 to 0.8 %) and cushions (from 1.7 to 0.4 %) and no significant effects on legumes. Only the annual grasses increased under the burned patches. According to the T-test results of total biotic interactions, fire facilitated species but it was not significant for functional groups.
Ali Asghar Naghipour borj; Jamaladdin Khaeddin; Hosein Bashari; Majid iravani; Pejman Tahmasebi
Volume 23, Issue 3 , January 2017, , Pages 442-453
Abstract
The structure and composition of plant communities are mainly affected by fire and grazing, especially in arid and semiarid rangelands. This study aimed to investigate the role of fire and grazing on soil seed bank characteristics (density, diversity and species richness) in semi-steppe rangelands of ...
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The structure and composition of plant communities are mainly affected by fire and grazing, especially in arid and semiarid rangelands. This study aimed to investigate the role of fire and grazing on soil seed bank characteristics (density, diversity and species richness) in semi-steppe rangelands of Central Zagros. A stratified random sampling was used to collect the data from 12 sites with one and five years after the last fire, and with long term light and heavy grazing history. Soil samples were collected in the autumn by auger from 0-5 and 5-10 cm from the soil surface, and the samples were cultivated in the greenhouse. All the germinated seeds were identified and counted for a 6-month period. The results showed that the one year after fire treatment under both light and heavy grazing resulted to a significant decrease in density, richness, and diversity of the soil seed bank. The richness and diversity of soil seed bank in the five-year after fire treatment and under light grazing pressure increased significantly compared to its control site. According to the results, the soil seed bank in 5 to 10 cm from the soil surface did not vary statistically under fire and grazing pressure, indicating the role of soil depth in reducing the impact of fire and grazing. Overall, it can be concluded that the grazing management after a fire event has a key role in vegetation restoration through its effects on the soil seed bank.
Aezam Khosravi Mashizi; Gholamali Heshmati; Najmeh Faryabi
Volume 21, Issue 4 , March 2015, , Pages 571-579
Abstract
Negative and positive interactions among plants have important role for species coexistence and community diversity. The strength and direction of the interaction effect may change with environmental disturbances such as grazing and fire. This study was aimed to evaluate the effects of environmental ...
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Negative and positive interactions among plants have important role for species coexistence and community diversity. The strength and direction of the interaction effect may change with environmental disturbances such as grazing and fire. This study was aimed to evaluate the effects of environmental disturbances such as fire and grazing on interactions between shrubs and herbs in rangelands of Goghar Bafte. Hence, beneath 20 dominant species of Artemisia aucheri and 20 open patches, a quadrate of 20 cm×20 cm was plotted and the variation in the biomass, richness and vegetation cover of herbs were measured in regions under exclosure, fire and grazing. Results showed that biomass and vegetation cover of herbs were increased by shrub presence because of positive interaction between shrubs and herbs inside exclosure. Although the facility of shrubs was reduced by grazing and fire, its rate was not equal in both places. Under grazing, interaction between shrubs and herbs remained positive but shrubs were severely damaged by fire and the interaction between species altered from positive to negative. The overall conclusion is that fire plays a more important role in changing the interaction between shrubs and herbs.
Mohammad Matinizadeh; Mahmoud Gudarzi
Volume 20, Issue 1 , June 2013, , Pages 213-225
Abstract
Fire can severely affect vegetation and soil and prevent different cycles of ecosystems. Enzymes quantities are sensitive indices for soil quality, and the changes in their activity can affect the ability of ecosystem and alter nutrient uptake by plants. This investigation was carried out in Kordan rangeland ...
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Fire can severely affect vegetation and soil and prevent different cycles of ecosystems. Enzymes quantities are sensitive indices for soil quality, and the changes in their activity can affect the ability of ecosystem and alter nutrient uptake by plants. This investigation was carried out in Kordan rangeland in spring and autumn for two years. Soil was sampled from 0-20 cm depth. Three enzymes including acid phosphatase, alkaline phosphatase and dehydrogenase were assessed by reaction with substrate. Our results showed that the activities of all studied enzymes were significantly higher in soils in September at both areas. However, this difference was not high for alkaline phosphatase. Two years after fire, the activity of all studied enzymes was higher at control site. The reasons for this decrease may be due to the destruction of enzymatic system and increasing inorganic phosphate because of fire. Three years after fire, the activity of enzymes increased and for alkaline phosphatase and dehydrogenase was more than control site. These enzymes are considered as biological indices for soil microorganisms therefore, it can be expected that its increase indicates increasing microbial biomass in fire area.