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SCI论文目录 |
Effects of crust and shrub patches on runoff, sedimentation, and related nutrients (C,N) redistribution in the desertified steppe zone of the Tengger Desert, Northern China |
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| 出 版 社：Geomorphology |
| 发表时间：2008, 96: 221-232 |
| 台 站：
沙坡头沙漠试验研究站
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| 作 者：李小军 |
| 点 击 率：4655 |
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| 关 键 字：Desert shrubland,Water erosion and sedimentation,Resource redistribution,Source-sink relationships, Ecological control on |
| 摘 要：Runoff and erosion are critical geomorphic processes in arid ecosystems, and they are strongly affected by vegetation patterns.
Little is known about the influence of spot-structured vegetation on runoff and erosion in temperate deserts; especially the effects of
vegetation patterns and human-induced disturbances on runoff-triggered nutrients redistribution are poorly understood. A series of
simulated rainfall experiments were conducted in the Tengger Desert, northern China, to examine (1) the effects of shrub patches
on runoff and erosion and related nutrients redistribution on hillslopes, (2) whether different amounts of water and nutrients are
stored in the shrub patches compared to open inter-patch areas, and (3) how the runoff and erosion and related nutrients
redistribution processes respond to human-induced disturbances. The results indicate that in undisturbed plots 53% of the applied
water became runoff from crust patches and 55% of this was redistributed to the shrub patches. Water penetration was significantly
deeper in shrub patches than in crust patches, and more than 75% of the sediments, 63% soil carbon, 74% nitrogen and 45∼73%
dissolved nutrients triggered by runoff from crust patches were delivered to shrub patches. The disturbance of crust patches tended
to result in the uniform distribution of water over the whole slope and the reduction of flow of vital resources from the crust patches
to the shrub patches. Disturbance of macrophytic patches significantly degraded the capacity for resource capture and retention and thereby decreased resources, all of which are crucial for the maintenance of plant productivity and vegetation cover. The
understanding of the function of patterned vegetation in the study area suggests that it represents an aspect of the ecosystem that
requires careful management. |
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