| 半干旱草地上的生态地理响应: 综述 |
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| 作者姓名： | I. STAVI H. LAVEE E. D. UNGAR P. SARAH |
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| 作者单位： | I.STAVI,H.LAVEE,P.SARAH(Laboratory of Soil and Geomorphology,Department of Geography and Environment,Bar Ilan University,Ramat Gan 52900 Israel);E.D.UNGAR(Department of Agronomy and Natural Resources,Institute of Plant Sciences,Agricultural Research Organization,the Volcani Center,Bet Dagan 50250 Israel)
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| 摘 要： | The ecogeomorphic processes occurring on semiarid rangelands are reviewed, with emphasis on the source-sink relations and positive feedback loops that existed between shrub patches and intershrub areas, and the way livestock presence affected these interactions. Compared with intershrub areas, the shrub patches had a higher soil porosity, infiltration capacity, water-holding capacity, hydraulic conductivity, structural stability, and organic matter content, and lower bulk density. These differences derived from a host of processes whose intensity was less in the shrub patches, including raindrop impact, mechanical crust formation, overland water flow, soil erosion, evaporative moisture loss, and flock trampling. There was also greater shading of the soil surface; soil and litter deposition; water accumulation; microbial, fungal, and mesofaunal activities in the shrub patches. The overland flow of water carried soil and litter from the intershrub areas to the shrub patches and resulted in microtopographic modifications that tended to strengthen these source-sink relations. Grazing had an impact on these processes, not only at the shrub-intershrub scale but also within the intershrub areas, through the creation of highly compacted trampling routes. The combined role of the above ecogeomorphic processes was to maintain the rangeland’s functionality. Without these inter-relationships, water loss, soil erosion, and nutrient depletion would occur at the hillside scale, causing degradation of the landscape.
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| 关 键 词： | 半干旱 牧场 反馈 土壤孔隙度 水力传导系数 源库关系 土壤侵蚀 有机质含量 |
| 收稿时间： | 9 November 2008 |
Ecogeomorphic feedbacks in semiarid rangelands: A review |
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| I. STAVI,H. LAVEE,E. D. UNGAR,P. SARAH.Ecogeomorphic feedbacks in semiarid rangelands: A review[J].Pedosphere,2009,19(2):217-229. |
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| Authors: | I STAVI H LAVEE E D UNGAR and P SARAH |
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| Institution: | [1]Laboratory of Soil and Geomorphology, Department of Geography and Environment, Bar Ilan University, Ramat Gan 52900 Israel [2]Department of Agronomy and Natural Resources, Institute of Plant Sciences, Agricultural Research Organization, the Volcani Center, Bet Dagan 50250 Israel |
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| Abstract: | The ecogeomorphic processes occurring on semiarid rangelands are reviewed,with emphasis on the source-sink relations and positive feedback loops that existed between shrub patches and intershrub areas,and the way livestock presence affected these interactions.Compared with intershrub areas,the shrub patches had a higher soil porosity,infiltration capacity,water-holding capacity,hydraulic conductivity,structural stability,and organic matter content,and lower bulk density.These differences derived from a host of processes whose intensity was less in the shrub patches,including raindrop impact,mechanical crust formation,overland water flow,soil erosion,evaporative moisture loss,and flock trampling.Thcre was also greater shading of the soil surface;soil and litter deposition;water accumulation;microbial,fungal,and mesofaunal activities in the shrub patches.The overland flow of water carried soil and litter from the intershrub areas to the shrub patches and resulted in microtopographic modifications that tended to strengthen these source-sink relations.Grazing had an impact on these processes,not only at the shrub-intershrub scale but also within the intershrub areas,through the creation of highly compacted trampling routes.The combined role of the above ecogeomorphic processes was to maintain the rangeland's functionality.Without these inter-relationships,water loss,soil erosion,and nutrient depletion would occur at the hillside scale,causing degradation of the landscape. |
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| Keywords: | intershrub areas shrubs soil resources trampling routes |
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