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Some Introductory Remarks on the Coryneform Bacteria   总被引:2,自引:2,他引:0  
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竹亚科系统学和生物地理学研究进展及存在的问题   总被引:8,自引:1,他引:8  
郭振华  李德铢 《云南植物研究》2002,24(4):431-438,462
对近年来在竹亚科作为一个单系类群的界定、其系统位置的确定、内部系统演化趋势以及地理分布和起源方面研究所取得的进展进行了评述。竹亚科作为一个单系类群仅包括了木本的竹族(Bambuseae)和一个草本的莪利竹族(Olyreae),其中莪利竹族分布在新几内亚的伊里安竹(Buergersiochloa)处于Olyreae最基部。禾本科12个亚科中除了3个亚科为基部类群以外,其余9个亚科分成PACCAD(包括黍亚科,狭义的芦竹亚科,广义的虎尾草亚科,假淡竹叶亚科,三芒草亚科和扁芒草亚科)和BOP单系分支(包括竹亚科,稻亚科和早熟禾亚科)。在BOP支中,竹亚科与早熟禾亚科相近缘,共同组成稻亚科的姐妹群。竹亚科分成草本和木本两个单系类群,木本竹子又分成热带和温带支系,热带支系进一步分成新世界热带和旧世界热带两个单系类群。从现有的化石证据和基部类群的地理分布推断,竹亚科很可能起源于晚白垩纪的冈瓦纳古陆。最后,本文就竹亚科研究尚存在的问题做了初步探讨。  相似文献   

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Some Remarks on the Socio-Cultural Background of Restoration Ecology   总被引:2,自引:0,他引:2  
Restoration ecology plays an important role in nature conservation policy in Europe today. It establishes the scientific basis for restoring ecosystems altered or destroyed by man to a more “natural” state. The goals of restoration ecology can generally be described in terms of increased biodiversity, enhanced water retention capacity, avoidance of soil erosion, etc. In practice, however, a discrepancy exists between the high ideals of restoration goals and reality, where one often encounters limiting factors. These limiting factors can include the conflict between different restoration goals, the unpredictability of restoration goals owing to long‐term effects and stochastic events, the insufficient social acceptance of landscape changes during restoration processes, and the use of restoration processes themselves (e.g., undisturbed succession, certain management measures like impoverishment of fertilized areas) as restoration goals in place of a certain resource quality (such as species composition, population sizes, water quality). Two examples from southern Germany show that restoration goals in European cultural landscapes can only be implemented successfully when they are integrated into the respective land use systems.  相似文献   

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《Ibis》1923,65(2):211-217
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