morteza Khodagholi; Razieh Saboohi; Alireza Eftekhari; Mina Bayat
Volume 31, Issue 4 , January 2025, , Pages 363-381
Abstract
Background and purpose:Increasing awareness of the environment and efforts for sustainable management of natural resources require study and monitoring in different time scales and places. Continuous changes should be considered as an inseparable part of any ecosystem. As natural ecosystems, rangelands ...
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Background and purpose:Increasing awareness of the environment and efforts for sustainable management of natural resources require study and monitoring in different time scales and places. Continuous changes should be considered as an inseparable part of any ecosystem. As natural ecosystems, rangelands are not exempt from this issue. So that rangeland monitoring is necessary in the sense of continuous investigation of these lands with regard to the ecological importance, economic functions and constant changes of these resources. Access to such data is extremely important both for national planning and for the use of rangelands, and it provides the basis for the use of advanced facilities such as remote sensing. Based on this, in order to monitor the trend and intensity of changes in vegetation cover and soil indicators of rangelands for 4 years at the Goorab site located in Isfahan province, it was evaluated and monitored.Materials and methods:The site of Goorab Fereydoonshahr Isfahan is located 230 kilometers west of Isfahan city and 35 kilometers west of Fereydoonshahr city. Plant factors including canopy cover of plant species and production rate of plant species and percentage of dead leaves were evaluated. Evaluation was done in the first year by random-systematic method and in the following years systematically with sufficient number of samples and appropriate distribution of samples in the plant type determined at the time of rangeland preparation. Soil sampling was done in theResults:The results showed that the 4-year average vegetation canopy cover percentage of Goorab site is about 42.2%, and the highest and lowest coverage is 59.4% in 1398 and 31.6% in 1400, respectively. The production rate is 1374.2 kg of dry matter per hectare. The production, like the canopy cover percentage, shows a lot of changes during the 4-year evaluation at the Goorab site, so that in 2019, the production reached 1957 kg per hectare, and in 2021, it decreased by 50% compared to 2019 to 955.7 kg per hectare. The results of the correlation and regression test also showed that the amount of precipitation in the growing season had the highest correlation with the amount of crown cover and production of plants in the region.Conclusion:Considering the importance of rangelands, both in terms of production and in terms of environmental values and services they provide to the society, studying the changes of rangelands in terms of the aforementioned factors and knowing the factors of those changes will be an effective help in developing a basic management plan and sustainable use of rangelands.
Masome Narouei; Morteza Khodagholi; Razieh Saboohi
Volume 31, Issue 3 , September 2024, , Pages 284-300
Abstract
Abstract Background and objectives:Knowing the effective environmental factors in the establishment of vegetation can help the proper management of pasture ecosystems. A suitable habitat has a significant effect on the survival and reproduction of species. Revealing changes in climate ...
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Abstract Background and objectives:Knowing the effective environmental factors in the establishment of vegetation can help the proper management of pasture ecosystems. A suitable habitat has a significant effect on the survival and reproduction of species. Revealing changes in climate parameters indicates that climate changes have started in Iran and it is necessary to determine the potential habitats of indicator species, now and in the coming years, under climate warning models. With the advancement of statistics and geographic information system, it has become possible to predict the habitat of plant species using modeling methods. Therefore, this research was conducted with the aim of preparing a forecast map of Platychaete aucheri habitats based on the climate forecast model in Sistan and Baluchestan province.Methodology:First, using 8 synoptic stations inside and nearby areas, the database including precipitation variables, night temperature, daily temperature and average temperature, from the year of establishment of each station until 2019, and 19 climate parameters were calculated. Also, three physiographic variables, including slope, direction and height, were prepared using a digital height model with an accuracy of 30 meters. Then, by using the updated maps of the ecological zones recognition plan and field visits, the presence and absence points of P.aucheri species were determined. The basis of the analysis used in this research is logistic regression, which is based on environmental values related to the presence and absence of species. Using logistic regression, the growth behavior of this species in Sistan and Baluchestan region was determined and the map was modeled and the relevant equations were calculated in the current conditions. After ensuring the efficiency of the model, the climate data predicted by the general circulation model MRI-ESM2-0 were used under the scenarios 4.5 and 8.5, and by using the current equations and placing the data extracted from the database, Worldclime, the future distribution map of the species P.aucheri was produced for 2050 under RCP4.5 and RCP8.5 climate scenarios. In this way, at the stage of defining the logistic regression model in ArcGIS, instead of the map of the climate variables that exist in the model, the maps of the same variables predicted for the year 2050 were placed.Results:The results of the potential maps showed that the current distribution of the species, P.aucheri, had a more colorful presence in the central and southern parts, and the percentage of the presence of the species decreased by moving towards the northern regions. The area of suitable habitat (probability of occurrence greater than 75%) of P.aucheri species in the province is equal to 12873269 hectares, approximately 71%. The evaluation of the model was done using the data of the presence and absence of the species and using the Kappa statistical coefficient. In this connection, the value of the Kappa statistical coefficient was obtained as 0.85, which according to the presented classification of the Kappa coefficients, the model has good and acceptable accuracy. It is acceptable. The maps resulting from the prediction of the logistic regression model show that the habitat area of P.aucheri species will increase significantly in 2050 under both RCP4.5 and RCP8.5 scenarios, and it is observed that the habitat area of P.aucheri species is more than 75% more likely to occur. In the province, it will be equal to 15506391 and 17788376 hectares, respectively, which will occupy a surface equivalent to 85.3 and 97.85%, respectively. Under the RCP8.5 scenario, the probability of the presence of the species will increase greatly, and it can be seen that the probability of the presence of this species in the lower floors reaches 50% to zero. Conclusion:In general, climate change and the consequent increase in temperature indicators will preserve the current habitat, increase the probability of the presence of the species in the entire province, and the vertical expansion of the P.aucheri species and its movement to higher latitudes along the altitude gradient of the region. Therefore, the expected upper limit of the vegetative range of P. aucheri species will undergo changes during the next three decades.
Farzad Heidari moorchekhortei; Mohammad Khosroshahi; Razieh Saboohi; Morteza Khodagholi; Leila Kashi Zenouzi
Volume 30, Issue 2 , September 2023, , Pages 196-213
Abstract
Background and objectivesResearch has been done on different materials to control and reduce wind erosion. Among them, we can mention the performance of agar gum biopolymer in reducing dust production at different concentrations of 0.5, 1.0, and 1.5%. Its results showed that the addition of biopolymer ...
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Background and objectivesResearch has been done on different materials to control and reduce wind erosion. Among them, we can mention the performance of agar gum biopolymer in reducing dust production at different concentrations of 0.5, 1.0, and 1.5%. Its results showed that the addition of biopolymer improves the water-holding capacity, increases the surface and compressive strength of the soil, and decreases dust production. In another study, agar gum biopolymer significantly improved soil mechanical properties. This study investigates the effect of polymer nuclei (M19) on controlling sand dunes. This research investigates the effect of nucleos (M19) mulch on reducing wind erosion and controlling sand dunes and dust. MethodologyThis research was carried out in Segazi Plain, a study and implementation priority due to its proximity to urban areas, military facilities, transportation, as well as industries and workshops located there, from the aspect of preventing wind erosion and desertification. After choosing the field, two plots of 500 square meters with the same conditions (an active hill with an area around it with natural and hand-planted vegetation) were selected. To determine the effect of soil cover, the area of each plot was determined by wooden stakes. In addition, the surrounding sand dunes were staked to measure their displacement. A pump sprayer mulched the measuring plot with nucleos (M19) mulch. Following the soil moisture changes, information including seedling survival and growth rate, soil cover's ability to control sand dune displacement, and compressive stress was examined during different months. Finally, the effectiveness of soil cover was compared with the control treatment using the T-test. Results The results of examining the changes in humidity and the effect of soil cover on it showed that the highest humidity in the area was after rain. No clear difference was observed between the drying process of the control plot and the mulched plot. It was also found that this mulch positively affects seedling growth rates. During the research period, the control sand dunes moved about 0.75 to 2.5 meters depending on the season and wind direction. In contrast, the mulched sand dunes remained stable. On the other hand, with time, the mulched field's surface became flaky, and signs of wear and tear were observed.ConclusionThe first point about using this polymer as a soil cover is its two phases during transportation and storage until mulching. In such a way, the two layers can be clearly distinguished. As a result, mixing is necessary for the uniformity of the polymer during the preparation of the final emulsion. This can be considered as one of the negative characteristics of the used polymer. This mulch positively affected soil moisture changes and increased soil moisture retention. On the other hand, the comparison of the growth of the seedlings in the mulched field and control also shows its effect on the growth of the seedlings. This soil cover's only positive and critical feature is its high flexibility after mulching in such a way that it is possible to drive on it with caution. Finally, after a year, cracks were first detected in the research field. Gradually, the number and depth of cracks increased, which caused the mulched field surface to become flaky. Following this complication, instability and signs of wear and tear were observed in the mulched area. However, no movement or change in location was observed in the mulched hill. It should be noted that with time, more destruction occurs on the surface of the mulched area. Following more flaking, the mulched surface may be destroyed, and hill erosion may begin. Considering these cases, mulching in this and similar areas is not recommended.