Farhad Aghajanlou; Peyman AKBARZADEH; alireza eftekhari
Volume 31, Issue 4 , January 2025, , Pages 323-333
Abstract
IntroductionIncreasing awareness of the environment and efforts for sustainable management of natural resources require study and monitoring at different timescales and places. Continuous changes should be considered integral to any ecosystem. As natural ecosystems, Rangelands are not exempt from this ...
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IntroductionIncreasing awareness of the environment and efforts for sustainable management of natural resources require study and monitoring at different timescales and places. Continuous changes should be considered integral to any ecosystem. As natural ecosystems, Rangelands are not exempt from this issue. Therefore, Rangeland monitoring is a necessary part of the continuous investigation of these lands, considering their ecological importance, economic function, and potential for permanent changes.Research MethodologyIn order to monitor the trend and intensity of changes in the vegetation cover and soil indicators of the Rangelands over a 5-year period, ground data were evaluated and monitored at dagestan, a site in Zanjan province. The measurement of ground information includes plant and soil factors. Plant factors include the percentage canopy cover of the plant species, the percentage of leaf litter, the density of plant species (in the areas and species that can be investigated), the production of plant species, the condition of the Rangeland, and the tendency of the Rangeland. Evaluation was performed using an appropriate method with sufficient samples and proper distribution in different plant communities during Rangeland preparation and repetition. Soil factors include acidity, electrical conductivity, nitrogen, phosphorus, potassium, organic matter, apparent specific gravity, and soil texture.Results and discussionThe results of the statistical analysis of the measurement of vegetation changes and its effect on soil indicators under the influence of two modes of grazing and flood during a 5-year period were evaluated; The results showed a significant difference between most of the indicators, and in this regard, the amount of total crown coverage and the amount of total production of the Rangeland between the studied years and the type of site were significantly different at the 1% and 5% probability levels, respectively. The highest amount of vegetation cover (56%) was in the grazed area in 2018 and the lowest amount was in the Preserve site (30%) in 1400. The highest total production was at the Preserve site (126 grams per square meter) in 2018, whereas the lowest amount (48.7 grams per square meter) was produced at the preserve Site at 1400. The results of the total species density analysis indicated that there were no significant differences between years and site types, but an interaction was observed between site types and years. However, by comparing the average values of the data, we found that the density of shrubs outside preserveWas higher than that of the grass inside the arq, and the difference was significant. Vegetation under the influence of two types of flooding and grazing can influence some parameters related to soil indicators. The study of the soil in the area under the influence of grazing pressure showed that the increase in the intensity of grazing has caused a decrease in the amount of potassium, phosphorus, nitrogen, organic carbon and electrical conductivity of the soil surface.ConclusionIn general, during the 5-year period, changes in vegetation due to grazing were significant, and the reduction in vegetation had a significant effect on the physical and chemical properties of soil. According to the results, the process of vegetation change in the studied area was slow and was influenced by rangeland management methods. As a result, examining the qualitative and quantitative changes in Rangeland vegetation in certain time intervals and being aware of their conditions is an important part of planning and applying Proper management is the exploitation of rangelands.
Hasan Ghelichnia; Alireza Eftekhari
Volume 31, Issue 1 , June 2024, , Pages 28-52
Abstract
AbstractBackground and objective: The monitoring and evaluation rangelands provides the necessary information for the essential planning of rangeland management. As a result, it prevents the destruction of rangelands and water and soil conservation. This research aims to prepare a continuous database ...
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AbstractBackground and objective: The monitoring and evaluation rangelands provides the necessary information for the essential planning of rangeland management. As a result, it prevents the destruction of rangelands and water and soil conservation. This research aims to prepare a continuous database of vegetation and soil indicators in rangelands and monitor their changes, determine the relationship between vegetation indicators and climatic factors, determine the trend and intensity of changes in different managements, and provide information for calculating the long-term capacity of rangelands.Methodology: For this study, the Asbchar site was selected in the rangelands of the Baladeh region in Mazandaran province and was evaluated and monitored for five years (2017-2021). In order to evaluate the indicators of vegetation cover, three transects of 100 meters were placed at a distance of 50 meters from each other. Vegetation and soil factors were measured. Vegetation factors included canopy cover, density and production of plant species, litter, rangeland condition and trend. Soil factors include pH, E.C., nitrogen, phosphorus, potassium, organic matter, soil bulk density and soil texture. Ten plots of 1m2 were placed in each transect, and a total of 30 plots were placed in exclosure and grazed areas. The crown cover of any plant species with the method of measuring the crown surface, the density by counting the number of species, the production by cutting and weighing, and the percentage of stone and gravel cover, litter, and bare soil were also measured in the plots. Data testing was done in Minitab16 software.Results:The analysis of variance results has shown a significant difference between most vegetation and soil factors in different years. The comparison of the averages of vegetation and soil factors investigated in different years shows that the highest average percentage of the total cover was related to the exclosure region. The highest average value was related to 2010, 2021 and 2019, respectively, and the lowest was the year 2017. The correlation between the total cover of the exclosure region with the total production, the percentage of nitrogen inside and outside the plant, the amount of potassium outside the plant, the annual rainfall, the rainfall of the growing season and the rainfall of autumn and winter seasons in exclosure region is significant. Also, the correlation between total production and annual rainfall, rainfall in the growing season and rainfall in autumn and winter seasons is significant. The correlation between total cover with total production, nitrogen percentage under plants, annual rainfall, growing season rainfall and autumn and winter rainfall in the grazed area is significant. Also, the correlation between total production with rainfall in the growing season and rainfall in the autumn and winter seasons is significant. The step-by-step regression results showed that climatic factors such as growing season rainfall, total fall and winter rainfall, and soil factors such as E.C., pH, % O.M. and %N were used to predict the total cover and production.Conclusion: The results of this research show a significant difference between the total crown cover, production and density of species during five years. Also, there is a significant difference between the exclosure and grazed areas in terms of all the factors examined in this research. The percentage of coverage, production and density of the perennial grasses and forbs in the exclosure region was higher than in the grazed region. The research results over five years showed that when autumn and winter rainfall and total rainfall and rainfall in the growing season were greater, an increasing trend was also seen in vegetation characteristics.
Zahra Jaberalansar; Babak Bahreininejad; Alireza Eftekhari; Masoud Borhani
Volume 30, Issue 3 , January 2024, , Pages 424-440
Abstract
Background and objectivesThe study of vegetation changes under habitat protection conditions has a significant role in rangeland management. The studies confirm that permanent changes in rangelands in terms of plant composition, canopy cover, and forage production are influenced by ecological and management ...
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Background and objectivesThe study of vegetation changes under habitat protection conditions has a significant role in rangeland management. The studies confirm that permanent changes in rangelands in terms of plant composition, canopy cover, and forage production are influenced by ecological and management factors. This research was conducted to investigate and monitor the plant vegetation indices of semi-steppe rangelands of central Zagros for five years (2016-2020) at the Zayandehrud watershed management research site (Isfahan province). Methodology Vegetation sampling was performed by a systematic random method in each exclosure and grazed site during 2016-2020. Vegetation characteristics, including the percentage of canopy cover of species, the percentage of gravel, bare soil, and litter were determined in each plot. For this purpose, four 100-meter segments were used. Then, ten plots (with 1 x 1-meter dimensions) were established with the same distance. In total, vegetation cover was measured in 80 plots of one square meter in exclosure and grazed sites. To calculate rangeland production, ten samples of each plant species were collected, and their canopy cover percentage was measured. After drying and weighing the samples, by establishing regression equations between the canopy cover percentage and the weight of the dried samples, the amount of production of plant species was determined separately for growth form and palatability class. Rangeland's condition was also evaluated according to the four-factor method and by scoring the factors of soil, vegetation, plant composition and age classes, and plant vigor. After collecting the data in Microsoft Excel, the variance analysis for the vegetation traits was done as a completely random design in a factorial format. This was done through the GLM (General Linear Model) method. Tukey's test investigated vegetation traits mean comparison in MINITAB 16 software. ResultsThe analysis of variance showed a significant difference between vegetation indices, including total canopy cover and production, separately for growth form and palatability class. This was in the exclosure and grazed sites during the assessment period. The average percentage of canopy cover in exclosure sites during different years was 26.7%, 13.7%, 25.84%, 33.74%, and 13.33%. In grazed sites, it was 22.33%, 12.65%, 27.09%, 30.9%, and 11.59%, respectively. Total production at the exclosure site during different years was 624.26, 349.86, 556.79, 894.54, 664.53 kg/ha. Production at the grazed site was 456.45, 243.85, 455.6, 605.47, and 323.44 kg/ha, respectively. The highest values of canopy cover and production belonged to 2019, which was a wet year based on meteorological indices. The lowest canopy cover and production were assigned to 2017 (a drought year). The highest amount of litter was found at the exclosure site. The highest percentage of bare soil and annual plant canopy cover was obtained from the grazed site. The highest percentage of canopy cover and production in the exclosure site belonged to Stipa hohenackeriana. At the grazed site, Hedysarum criniferum and Stipa hohenackeriana accounted for the highest canopy cover and production, respectively. According to the four-factor method, the rangeland condition at the disclosure site was fair in 2016, 2018, and 2019 and poor in 2017 and 2020. At the grazed site, the rangeland condition was fair in 2018 and 2019 and poor in the rest of the years. Conclusion The comparison of vegetation parameters inside and outside the exclosure shows the good condition of vegetation inside the exclosure. It also shows the effectiveness of the exclosure in rangeland rehabilitation. Balanced livestock grazing on the vegetation caused no significant difference between vegetation characteristics, such as canopy cover in the exclosure and grazed sites. Continuous evaluation and monitoring of rangelands through creating a regular database of vegetation indicators and investigating their changes under different managements. This investigation of their relationship with climatic factors can provide the necessary background for fundamental rangeland planning and management.
Fatemeh Hadian; Seyed Zeinolabedin Hoseini; Mansoureh Seyed Hoseini
Volume 21, Issue 4 , March 2015, , Pages 756-768
Abstract
Precipitation is one of the factors affecting vegetation. Nowadays, satellite images are broadly used for monitoring the effects of precipitation variations on the vegetation changes. The aim of this study was to investigate the relationship between vegetation dynamic and precipitation variations using ...
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Precipitation is one of the factors affecting vegetation. Nowadays, satellite images are broadly used for monitoring the effects of precipitation variations on the vegetation changes. The aim of this study was to investigate the relationship between vegetation dynamic and precipitation variations using NOAA AVHRR images during the period of 1982-2006. Precipitation maps were created using the inverse distance weighting interpolation (IDW) method and time intervals of precipitation data. The study area was a forestland beside Caspian Sea, four rangeland vegetation types with grasses and shrubs, farmland areas and urban areas, located in Ardabil and Guilan provinces. To monitor the relationship between the precipitation and vegetation changes, the linear regression (NDVI, Y & Rainfall, X) method was employed. Based on the results, depending on the precipitation time, plant species, and growth form, the effect of precipitation on vegetation was different so that no significant relationship was observed between vegetation and precipitation in forestlands, farmlands, and urban areas. The highest correlation coefficient between spring precipitation and vegetation was related to the rangelands. In grassland areas, the correlation coefficient was higher than that of shrublands, whereas the reaction of grasslands to precipitation in various parts was different.
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.
Rooh... Kazemi; Hassan Yeganeh; Jamal.. Khajedin
Volume 18, Issue 1 , May 2011, , Pages 124-138
Abstract
Accurate and up-to-date global land cover data sets are necessary for various global change research studies including climatic change, biodiversity conservation, ecosystem assessment, and environmental modeling. The aim of the present research was to study change detection of vegetation during the grazing ...
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Accurate and up-to-date global land cover data sets are necessary for various global change research studies including climatic change, biodiversity conservation, ecosystem assessment, and environmental modeling. The aim of the present research was to study change detection of vegetation during the grazing season using multi temporal data of WiFS in Semirom region. Various preprocessing, including geometric correction were applied using topographic maps of 1:250000 with an RMSe 0.35 pixel for sensor IRS-WiFS. The atmospheric and topographic corrections were carried out using dark-object subtraction method and the Lambert method. Field data collection was started on June 2005 on 800,000 ha. Multi-temporal data of IRS-WiFS sets were used for this study. Image processing including FCC, PCA, vegetation indices and supervised classification were employed to produce the vegetation canopy cover map. Various vegetation types were sampled using stratified random sampling method. twenty random sampling points were selected and canopy cover percentage was estimated. Digital data and the indices maps were used as independent data and the field data as dependent variables. The produced models were processed and then resulted images were categorized in 5 classes. Also post classification method was used to determine change detections. Finally the produced maps were controlled for their accuracies. The results confirmed the high correlations of used WiFS indices with field data. In the current study, more than 30 percent of the study area has been affected during the grazing season. Also the NDVI, SAVI and DVI indices which employ RED and NIR bands had relatively highly correlations with rangeland data. Result showed vegetation maps produced with IRS-WiFS data set had very high accuracy.