荒漠河岸植被的受损过程与受损程度的判定 |
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引用本文: | 刘加珍,;陈亚宁,;陈永金.荒漠河岸植被的受损过程与受损程度的判定[J].聊城师院学报,2009(3):75-80. |
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作者姓名: | 刘加珍 ;陈亚宁 ;陈永金 |
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作者单位: | [1]聊城大学环境与规划学院,山东聊城252059; [2]中国科学院新疆生态与地理研究所,新疆乌鲁木齐830011 |
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基金项目: | 国家自然科学基金(90502004,40671014,40871239)和国家973重点基础研究发展规划项目(2004CB720200/2004CB720201)资助 |
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摘 要: | 以多年平均地下水位数据为依据,将地下水位划分为6个环境梯度,各梯度上6次重复采集植被样地数据.从物种多样性、植被盖度等几方面分析了不同地下水位梯度上植被的受损过程,以及不同河段的受损程度.结果表明:(1)草本植物丰富度受损发生在地下水埋深大于4m,而木本植物丰富度受损发生在地下水埋深大于8m;(2)植被盖度减少始于草本植物盖度受损,与群落多样性受损的临界地下水位相同,发生在地下水埋深大于4m;在地下水埋深大于6m之后,植被盖度不断减少则是由木本植物盖度的减少所引起.(3)生态受损程度可归为三类:潜在沙漠化类(轻度退化),轻度沙漠化类(中度退化),中度或重度沙漠化类(重度退化).三种退化类型的地下水埋深依次增大,物种多样性与植被盖度依次减小,沙漠化指数也依次增强.
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关 键 词: | 物种多样性 植被盖度 受损过程 受损程度 |
The Degred Pross of Desert Riparian Ecosystem and It s Degree of Degradation |
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Institution: | LIU Jia-zhen,CHEN Ya-ning, CHEN Yong-jin (1.School of Environment & Planning,Liaocheng University,Liaocheng 252059,China;2. Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences, Urumqi 830011,China)) |
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Abstract: | Based on the data of mean annual groundwater level,we divided six gradients of groundwater levels and sampled six vegetation plots in every gradient of groundwater level. Through analyzing the changes in vegetation coverage, species diversity and structure of plant communities along the gradients of groundwater levels,we got the results to explain the degraded process of vegetation,at the same time,we analyzed the mechanism of vegetation degradation. The results showed. (1) Degradation of rich- ness of herbaceous plants happened at the 4 m groundwater level,while that of woody plants started at 8m depth of groundwater level. (2) The decrease of vegetation coverage was due to decline of herbaceous coverage. The threshold depth of ground water level for coverage degradation was 4 m. This depth was same with depth of groundwater for degradation of species diversity. However, depth of ground water was under 6 re,the decrease of vegetation coverage was due to decrease of coverage of woody plants. (3) The degraded ecosystem at the study area could be divided into three types by duster analysis namely the light degradation,the serious degradation and intergrade degradation. The slight degradation of ecosys- tem appears in the upper section of the lower reaches,with the relative shallow groundwater and high index of biodiversity and dense vegetation coverage. While the serious degradation of ecosystem can be found in the area near Taitema Nor. where the groundwater level is deeper more than 10 m,little species can survive. |
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Keywords: | species diversity cover of vegetation degraded process degree of degradation |
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