| Soil Erosion and Vegetation Succession in Alpine Kobresia Steppe Meadow Caused by Plateau Pika A Case Study of Nagqu County, Tibet |
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| 作者姓名： | WEI Xinghu LI Sen Yang Ping Cheng Huaishun |
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| 作者单位： | 1.Department of Geography，Foshan University，Foshan 528000，China; 2. Cold and Arid Regions Environmental and Engineering Research Institute，Chinese Academy of Sciences，Lanzhou 730000，China |
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| 摘 要： | This paper evaluated the impacts of mounds created by the plateau pika (Ochotona curzoniae) on the vege- tation composition, structure, and species diversity of an alpine Kobresia steppe meadow in Nagqu County, Tibet Autonomous Region, China. Based on mound height or the depth of erosion pit, we defined five stages of erosion and compared the floristic features of communities at these stages with those in undisturbed sites. In the study area, the mounds and pits covered up to 7% of the total area. Lancea tibetica, Lamiophlomis rotata, and Potentilla bifurca were the dominant species in erosion pits, and Kobresia pygmaea, the dominant species in undisturbed sites, became a com- panion species in eroded areas. In the process of erosion, the original vegetation was covered by soil ejected by the pika, then the mounds were gradually eroded by wind and rain, and finally erosion pits formed. The vegetation coverage in- creased with increasing erosion stages but remained significantly lower than that in undisturbed sites. Improved coverage eventually reduced soil erosion, and pit depth eventually stabilized at around 20cm. Aboveground biomass increased with increasing erosion stage, but the proportion of low-quality forage reached more than 94%. The richness index and Shannon-Wiener index increased significantly with increasing erosion stage, but the richness index in mound and pit areas was significantly lower than that in undisturbed sites.
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| 关 键 词： | 西藏 那曲县 土壤侵蚀 植被演替 高山草甸 高原鼠兔 危害 |
| 收稿时间： | 2006-08-10 |
| 修稿时间： | 2006-12-28 |
Soil erosion and vegetation succession in alpine <Emphasis Type="Italic">Kobresia</Emphasis> steppe meadow caused by plateau pika—A case study of Nagqu County,Tibet |
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| WEI Xinghu LI Sen Yang Ping Cheng Huaishun.Soil Erosion and Vegetation Succession in Alpine Kobresia Steppe Meadow Caused by Plateau Pika A Case Study of Nagqu County, Tibet[J].Chinese Geographical Science,2007,17(1):75-81. |
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| Authors: | Wei Xinghu Li Sen Yang Ping Cheng Huaishun |
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| Institution: | (1) Department of Geography, Foshan University, Foshan, 528000, China;(2) Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, 730000, China |
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| Abstract: | This paper evaluated the impacts of mounds created by the plateau pika (Ochotona curzoniae) on the vege- tation composition, structure, and species diversity of an alpine Kobresia steppe meadow in Nagqu County, Tibet Autonomous Region, China. Based on mound height or the depth of erosion pit, we defined five stages of erosion and compared the floristic features of communities at these stages with those in undisturbed sites. In the study area, the mounds and pits covered up to 7% of the total area. Lancea tibetica, Lamiophlomis rotata, and Potentilla bifurca were the dominant species in erosion pits, and Kobresia pygmaea, the dominant species in undisturbed sites, became a com- panion species in eroded areas. In the process of erosion, the original vegetation was covered by soil ejected by the pika, then the mounds were gradually eroded by wind and rain, and finally erosion pits formed. The vegetation coverage in- creased with increasing erosion stages but remained significantly lower than that in undisturbed sites. Improved coverage eventually reduced soil erosion, and pit depth eventually stabilized at around 20cm. Aboveground biomass increased with increasing erosion stage, but the proportion of low-quality forage reached more than 94%. The richness index and Shannon-Wiener index increased significantly with increasing erosion stage, but the richness index in mound and pit areas was significantly lower than that in undisturbed sites. |
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| Keywords: | plateau pika alpine Kobresia steppe meadow vegetation succession diversity Tibet |
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