فهرس المقالات Rangeland condition

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  1 - بررسی اکولوژیکی تغییرات وضعیت مرتع و ارتباط آن با گونه های سمی
  کوروش خلعتبری محمدحسن جوری حمیدرضا محرابی
  تغییرات شدید ساختار بهره برداری از مراتع باعث دگرگونی پوشش گیاهی مراتع شده است که هجوم گونه های سمی در مناطق عاری از پوشش گیاهان بومی بعنوان نمادی از این تغییرات مطرح است. آگاهی از درجات وضعیت مراتع باعث اتخاذ تصمیم درست مدیریت بهره برداری از مراتع می گردد. به منظور برر أکثر

  تغییرات شدید ساختار بهره برداری از مراتع باعث دگرگونی پوشش گیاهی مراتع شده است که هجوم گونه های سمی در مناطق عاری از پوشش گیاهان بومی بعنوان نمادی از این تغییرات مطرح است. آگاهی از درجات وضعیت مراتع باعث اتخاذ تصمیم درست مدیریت بهره برداری از مراتع می گردد. به منظور بررسی روند این تغییرات و ارتباط آن با حضور گونه های سمی، مراتع جواهرده رامسر تحت سه تیمار قرق بلندمدت (30 سال)، کوتاه مدت (7 سال) و منطقه چرایی انتخاب شد. به کمک پیمایش صحرایی اقدام به جمع آوری گونه ها و شناسایی آنها توسط منابع معتبر شد. تعدادی پلات به روش تصادفی در هر سایت به منظور تعیین وضعیت و گرایش انداخته شد. وضعیت مرتع به روش شش فاکتوره و گرایش نیز با استفاده از روش ترازوی گرایش تعیین شد. همچنین به منظور تعیین میزان مصرف گونه های سمی توسط دام، از روش شمارش لقمه استفاده شد. نتایج نشان داده است که در این منطقه 133 گونه متعلق 19 تیره و 56 جنس حضور دارند. همچنین با توجه به وضعیت خوب (قرق بلندمدت)، متوسط (قرق 7 ساله) و ضعیف (تحت چرا)، 39 گونه بصورت سمی بوده است. 46 گونه مورد مصرف دام قرار گرفت که از بین آنها 15 گونه دارای خاصیت سمی بوده اند. بنابراین مطالعه روند وضعیت مرتع در منطقه نشان داده است که در مواقعی که فشار چرایی شدید می گردد و یا اینکه مراتع تحت چرای مداوم قرار دارند، گونه های بومی عرصه را به نفع گونه های مهاجم (که اکثرا غیرخوشخوراک و سمی هستند) خالی می کنند. اما بعضی از گونه های سمی بومی نیز وجود دارند که با توجه به خاستگاه اکولوژیک خود، عرصه عاری از گونه های خوشخوراک را تحت اشغال خود درمی آورند. تفاصيل المقالة
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  2 - Climate Change Implications on the Rangelands Condition in West Guji and Borana Zones, Southern Ethiopia
  Tesfaye Dejene Gemedo Dalle Teshale Woldeamanuel Muluken Mekuyie
  Climate change is one of the most serious threats to rangeland. The implications of climate change on the rangelands conditions of the Duda and Gomole in Southern Ethiopia were examined. Measurements of rangeland were made using field survey and focus group discussions. أکثر

  Climate change is one of the most serious threats to rangeland. The implications of climate change on the rangelands conditions of the Duda and Gomole in Southern Ethiopia were examined. Measurements of rangeland were made using field survey and focus group discussions. Descriptive statistics, one way ANOVA was employed to detect whether significant difference exists between range conditions, while Pearson bivariate correlation used to test the relationships between climate factors and herbaceous plants. The Mann-Kendall test was used to determine the trends of rainfall and temperatures over times; meanwhile Sen's slope estimator was used to test the magnitude of changes. The results show that no significant annual rainfall trend was in both Duda and Gomole rangelands, despite a slight increase in rainfall. However, the annual minimum temperature significantly increases in Duda rangeland, while the annual maximum temperature significantly decreases in Gomole rangeland. The major herbaceous species in Duda rangeland (Cenchrus ciliaris, Cynodon dactylon, Digitaria naghellensi, Digitaria milanjiana and Panicum maximum) had positive correlation with annual rainfall and negative correlation with minimum temperature. In the Gomole rangeland, Cenchrus ciliaris and Bothriochloa insculpta negatively correlated with minimum temperature. The Duda rangeland was in poor condition where that of Gomole was in fair condition. This difference was mainly due to slight difference between climate of Duda (arid and semi-arid) and Gomole (arid) of the rangelands. The multiple linear regression model result showed that changes in rainfall and temperature accounted for 46% of variability on Duda rangeland condition, whereas rainfall changes accounted for 32% of variability on Gomole rangeland condition. Therefore, the present study suggests rangeland rehabilitation in the short run through soil and water conservation, bush clearing and burning, and the planting of desirable grass species are critical to reduce the effects of climate change on rangeland. تفاصيل المقالة
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  3 - Assessment of Range Health Changes in Zagros Semi-Arid Rangelands, Iran (Case Study: Chalghafa- Semirom-Isfahan)
  Ezatollah Moradi Gholam Ali Heshmati Ali Hosein Bahramian
  Rangeland health assessment provides qualitative information on ecosystemattributes. We examined changes in rangeland health in the Zagros semi-arid rangelands ofIran at fixed sites between 2001 and 2011, over the 10-year period. The rangelandfragments significantly dec أکثر

  Rangeland health assessment provides qualitative information on ecosystemattributes. We examined changes in rangeland health in the Zagros semi-arid rangelands ofIran at fixed sites between 2001 and 2011, over the 10-year period. The rangelandfragments significantly declines in the quality of the vegetation, and changes in plantspecies were driven largely by seasonality, and to a lesser extent, amount of rainfall. Threeindices of rangelands health (composition, function and stability) developed using sitebasedvegetation and landscape data. The results indicated that the majority of sites hadintermediate values of the three indices, and few sites had either very low or very highvalues. The indices of composition and function were strongly correlated with thesubjective ratings applied to each site at each measurement period. The results of this studyhighlight the difficulty of detecting change over extensive areas of rangeland, and ofseparating management induced effects from climatic effects in an environment whichexperiences wide spatial and temporal variation in rainfall. Results showed that soil surfaceresistance decrease and water flow pattern degradation were the most important causes inrangeland health decrease. Although, Chalghafa rangelands have enough rain falls tosupport habitation, humans had degraded the landscape. Moderate grazing is the best wayto use the grazing land without severe reduction in abundance and biomass of species. تفاصيل المقالة
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  4 - Studying the sffects of Grazing Capacity and Rangeland Conditions on Occurrence of Landslide in Subalpine Grassland (Case Study: Rangeland of Masoleh Watershed)
  Mona Fakhre Ghazi Mohammad Hasan Jouri Vahid Gholami
  Subalpine rangeland as a rara avis ecosystem is very important because ofecological features. Consistency and resistance of this ecosystem is so frangible and itsnatural equilibrium is instable due to the effects of biotic and abiotic factors. The landslideas one of neg أکثر

  Subalpine rangeland as a rara avis ecosystem is very important because ofecological features. Consistency and resistance of this ecosystem is so frangible and itsnatural equilibrium is instable due to the effects of biotic and abiotic factors. The landslideas one of negative consequences in upland area is seen in Masoleh watershed (north ofIran). This study has investigated the roles of biotic factors playing in the occurrence of thelandslides in Masoleh rangeland. Hence, two sites such as exclosure and grazing areaswere analyzed and compared. The plot size was 1m² and totally, 128 plots were obtainedby minimal area method and statistical formula approach, respectively. The rangelandconditions were measured by six-factor method. Clipping and weighing method was usedto determine the grazing capacity. In order to do the landslide zonation, the landslide indexwas employed. Results showed that there were significant differences between speciesdensities and soil conservation factors in both exclosure and grazing areas. There might bemore than 1.2 overstocking in the grazing area. The rangeland conditions‟ classes anddistance from fold, effective biotic factors, geologic formation, soil texture and effectiveabiotic factors were the most influential factors on the landslide occurrence in subalpineecosystem of Masoleh. Regarding results of current research, the exclosure can protect thesoil from the landslide through increasing the perennial and endemic species. Decreasinglivestock and regulating the animal entrance and egress to reach the suitable circumstancesof vegetation covers and pull up the landslide occurrence are recommended in this area. تفاصيل المقالة