فهرس المقالات Arid and Semi-arid

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  1 - ارزیابی کارایی استفاده از تغییرات خرد اقلیم در تفکیک پوشش اراضی در مقایسه ‏با برخی از روش‌های طبقه‌بندی نظارت‌شده در ‏محیط‌های شهری خشک
  نجمه ستاری ملیحه عرفانی فاطمه جهانی شکیب
  10.30495/girs.2023.689922
  تفکیک بین اراضی بایر و ساخت و ساز شده از یکی از مهم‌ترین مسائل در تهیه نقشه کاربری اراضی/ پوشش اراضی در اقلیم‌های خشک و نیمه‌خشک است. در این راستا پژوهشگران بسیاری سعی در افزایش دقت طبقه‌بندی از طریق به کارگیری روش‌های مختلف داشته‌اند که دنبال کردن برخی از روش‌ها پی أکثر

  تفکیک بین اراضی بایر و ساخت و ساز شده از یکی از مهم‌ترین مسائل در تهیه نقشه کاربری اراضی/ پوشش اراضی در اقلیم‌های خشک و نیمه‌خشک است. در این راستا پژوهشگران بسیاری سعی در افزایش دقت طبقه‌بندی از طریق به کارگیری روش‌های مختلف داشته‌اند که دنبال کردن برخی از روش‌ها پیچیده و زمانبر است. از این رو مقاله حاضر با هدف به کارگیری تغییرات خرد اقلیم از طریق اجرای الگوریتم پهنه‌بندی محلی اقلیم ( LCZ ) در شناسایی کاربری اراضی با تاکید بر تفکیک مناطق ساخت و ساز شده در یکی از شهرهای خشک ایران انجام شد و کارایی روش با بررسی صحت طبقه‌بندی در مقایسه با روش‌های مختلف نظارت شده شامل حداکثر احتمال، حداقل فاصله، فیشر، KNN، Artmapفازی، شبکه عصبی مصنوعی و ماشین بردار پشتیبان مقایسه گردید. منطقه مورد مطالعه شهر زاهدان بوده که دارای رشد مناطق ساخت و ساز شده بسیار چشمگیری در دهه‌های گذشته است. به این منظور از چهار دوره از تصاویر ماهواره لندست هشت سال 2020 استفاده شد. نمونه‌های تعلیمی از گوگل ارث استخراج شد و صحت‌سنجی نتایج طبقه‌بندی‌ها به کمک 218 نقطه تصادفی انجام شد. نتایج صحت‌سنجی نشان داد که استفاده از الگوریتم LCZ با صحت کلی و ضریب کاپای 33/96 درصد و 95/0 بالاترین و پس از آن روش‌های ماشین بردار پشتیبان و فیشر با صحت کلی 61/87 و 03/83 و ضریب کاپای 82/0 و 75/0 قرار دارند. از این‌رو برای مطالعات کاربری اراضی/پوشش اراضی روش LCZ که خرد اقلیم‌های محلی را در نظر می‌گیرد، پیشنهاد می‌شود. تفاصيل المقالة
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  2 - Application of Superabsorbent and Mulch on Some Traits of African Marigold (<i>Tagetes erecta</i>) under Irrigation Intervals
  Haidar Al-Obaidy Zahra Karimian Leila samiei Ali Tehranifar
  Water scarcity is an important obstacle to the development and expansion of the urban landscape in the arid and semi-arid regions of the world. Nowadays, organic and artificial materials can be used to reduce water consumption without impairing the quality and quantity أکثر

  Water scarcity is an important obstacle to the development and expansion of the urban landscape in the arid and semi-arid regions of the world. Nowadays, organic and artificial materials can be used to reduce water consumption without impairing the quality and quantity of urban landscape. In order to study the effect of mulch type on reducing irrigation interval for a popular seasonal plant in the Middle East, African marigold, an experiment was carried out in Mashhad, Iran during 2016-2017 in which two treatments were applied including mulch type (typical soil as control, palm fiber mulch, plastic mulch, and superabsorbent) and irrigation intervals (3, 6 and 9 days). Some morphological, biological, physiological and biochemical traits were evaluated. Results indicated that the superabsorbent could significantly increase most recorded traits. The palm fiber mulch also improved plant height, flower number, and dry shoot weight. In most traits, the 3-day irrigation interval indicated a significant increase versus the 6- and 9-day intervals, but plant height, flower number, and photosynthetic rate did not differ significantly between the 3-day and 9-day irrigation intervals. The findings show that superabsorbent and at the next level, palm fiber mulch with 9-day irrigation intervals can be suggested for African marigold in the arid and semi-arid climates. تفاصيل المقالة
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  3 - Comparative Study of Species Diversity in different Land Use Units of the Borana Lowlands, Southern Oromia, Ethiopia
  Gemedo Dalle
  Quantitative study of species diversity across different land use units and districts is important to document status of local plant biodiversity, to evaluate impact of management and for planning future management. This study aimed at determining impacts of land use un أکثر

  Quantitative study of species diversity across different land use units and districts is important to document status of local plant biodiversity, to evaluate impact of management and for planning future management. This study aimed at determining impacts of land use units on species diversity and spatial distribution of species in two districts of Borana zone, Oromia, Ethiopia. Stratification and systematic random sampling techniques were used for data collection. Plot size of 500 m2 for woody species and subplots of 0.25 m2 for herbaceous species and soil samples were used. Data was analysed using both descriptive and inferential statistics. Shannon diversity index and Simpson index were determined. Relationships between vegetation and environmental variables were analysed using Redundancy Analysis (RDA) and Canonical Correspondence Analysis (CCA). The overall mean alpha, beta and gamma diversities were 29.2, 2.5 and 102.6, respectively. Average total number of species in enclosures and open access grazing sites was 113 and 96 species, respectively. Enclosures or relatively protected land use units (Kalos) had more species diversity than their corresponding open access grazing lands (Worras). Shannon diversity index ranged from 3.11 in the grazing land for dry livestock to 3.78 in the Web grazing land for lactating cattle. Similarly, Simpson index of dominance ranged from 0.034 in the Web Worra to 0.089 in grazing land for dry livestock (Foora). Kalos had higher Simpson diversity index than their corresponding Worras. Soil nutrients varied across land use units. Cation Exchange Capacity (CEC) was higher in enclosed than in open access grazing land use units. The study also showed that there was significant variation in P, Ca, CEC, silt and sand across the two districts (p&lt;0.05). RDA and CCA results revealed that altitude, OM, K and N were the most important environmental variables that significantly accounted for the spatial distribution and abundance of species. It was concluded that enclosures had contributed to increased species diversity. Promoting the area enclosure as a viable strategy for biodiversity management and rehabilitation of rangelands were recommended as a result of this study. تفاصيل المقالة
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  4 - Plant Species and Functional Types’ Diversity in Relation to Grazing in Arid and Semi-arid Rangelands, Khabr National Park, Iran
  Mohsen Sharafatmandrad Adel Sepehry Hossein Barani
  In arid and semi-arid rangelands, grazing as one of the natural or human induced processes has direct and indirect effects on structure and dynamics of plant community and ecosystems. A study was done to analyze the effects of grazing on plant species diversity and Plan أکثر

  In arid and semi-arid rangelands, grazing as one of the natural or human induced processes has direct and indirect effects on structure and dynamics of plant community and ecosystems. A study was done to analyze the effects of grazing on plant species diversity and Plant Functional Types&lsquo; (PFTs) diversity of arid and semi-arid rangelands. We analyzed plant richness and diversity data from 75 sampling plots located in five bioclimatic zones of Khabr National Park containing a total of 73 plant species. Ward's hierarchical clustering was then used to cluster all plant species into eight PFTs according to the chosen traits. For each site, grazing intensity was estimated in three classes (low grazing, medium and high grazing intensities). We found that as grazing intensity increased, total species richness and diversity were decreased. Considering PFTs as total showed the same pattern for species; however, each PFT diversity and richness didn&lsquo;t display a significant different response to grazing. Looking at each PFT relative cover change in different grazing intensities showed that PFT1 and PFT8 were grazing sensitivities while PFT6 and PFT7 benefited from grazing and their relative cover increased consistently in response to the increased grazing intensity. PFT3 and PFT4 had the highest relative cover rates in moderately grazed areas. PFT2 and PFT5 had a complicated response to grazing and their relative cover was the minimum at moderately grazed sits. This finding may imply that grazing has completely negative impacts on the community structure and it seems that it reduces plant species and functional types&lsquo; diversity and richness. It can be also concluded that the analyses on PFTs level possibly give more insight into the grazing response of plant community in arid and semi-arid rangelands than those on species level but there is a need for further studies. تفاصيل المقالة
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  5 - Estimating Plant Biomass by Using Non-Destructive Parameters in Arid Regions (Case Study: Inche-Broun Winter Rangelands, Golestan, Iran)
  Naghmeh Gholami Baghi Adel Sepehri Hossein Barani Salman Abdol-Rasoul Mahini
  Plant biomass is an important factor for determining arid and semi-aridrangelands capacity. Due to the lack of proper and annual sampling of rangelands, there areno suitable data to determine biomass, range condition and proper range managementoperations. Plant biomass أکثر

  Plant biomass is an important factor for determining arid and semi-aridrangelands capacity. Due to the lack of proper and annual sampling of rangelands, there areno suitable data to determine biomass, range condition and proper range managementoperations. Plant biomass is one of the measurable attributes that can be assessed inrangeland studies. Since the clip and weight method is destructive and time-consuming,green biomass was estimated by using dimensional parameters (Plant Allometry) includingcanopy cover, length and width of diameters. Field sampling was done using seventy 2&times;2m quadrats along five 100 m transects. The data were analyzed by stepwise regression. Theresults showed that the fresh and dry biomass showed significant positive correlations withcanopy cover, the length and width of diameters of Halocnemum strobilaceum shrub(p&lt;0.05). The results of stepwise regression showed that just canopy cover and diameterlength were remained in the final model, so that 80.2% of biomass variations wereexplained by canopy cover and diameter length. تفاصيل المقالة
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  6 - Multivariate Statistical Method for Assessing Livestock Grazing Effects on Soil and Vegetation in Steppe Rangelands (Case Study: Steppe Rangelands of Saveh)
  Sedigheh Zare Kia Hossein Arzani Mohammad Jafari Seyyed Akbar Javadi Ali Ashraf Jafari
  This study aims to assess the effect of grazing intensity on vegetation structure, soil nutrient concentrations and soil physical properties. The study was carried out in steppe rangelands of Saveh, Markazi province, Iran. Four sites with four grazing intensities includ أکثر

  This study aims to assess the effect of grazing intensity on vegetation structure, soil nutrient concentrations and soil physical properties. The study was carried out in steppe rangelands of Saveh, Markazi province, Iran. Four sites with four grazing intensities including very high, high, moderate and non-grazed with the same ecological conditions were selected. To study various vegetation and soil parameters in each range site, a reference area was selected. Then, sampling was performed by randomized systematic method in reference areas. Vegetation characteristics, soil physical properties, bulk density, infiltration rate, soil texture and chemical constituents including nitrogen, phosphorus, potassium, pH, EC and organic carbon were measured. Principal component analysis was performed on a dataset with 22 variables to determine the effect of grazing intensity on vegetation structure and soil properties. Results indicated that the first three axes explained the total variation. The variables of potassium, phosphorous, bulk density, class I, class II, clay, field capacity, infiltration, Peganum harmala, Salsola laricina, Artemisia sieberi and perennial forbs had significant correlations with the first axes and explained a 74.27% variation. For the second components, silt, sand and perennial grasses were more important traits and explained a 15.5% variation. In non-grazed and moderate grazed sites, there were more canopy cover of both Artemisia sieberi and Salsola laricina, and for high grazing sites, there were plants of class III such as Noaea mucronata and Peganum harmala. The grazing intensity was associated with lower values of infiltration, clay percent and field capacity and higher values of bulk density, potassium, phosphorous and sand percent. Therefore, vegetation structure and soil properties were changed by the interaction between grazing intensity, soil properties and vegetation structure. The results suggested that excluding grazing livestock on the arid steppes has a great potential to restore vegetation and soil. Therefore, it must be encouraged as an alternative to stop further degradation and to combat desertification in arid and semi arid ecosystems. تفاصيل المقالة