【作者】 丁贤法；

【导师】 韩广；

【作者基本信息】 湖南师范大学 ， 自然地理学， 2005， 硕士

【摘要】 在环境条件不断变化的情形下,数十亿年来地球表层仍然维持了适宜大多数物种居住的较稳定的环境,盖亚假说认为这是由于生物群对环境进行调节并把它控制在一定环境范围之内的结果。最大熵产生(Maximum Entropy Production)假说认为一个远离平衡的开放系统向最大熵产生的定态演化。论文在对这两个假说的主要内容进行较详细的介绍与分析的基础上,以位于西北干旱区内蒙古西部的额济纳绿洲为例,运用这两个假说的主要思想和观点探讨和研究了该绿洲的生态恢复问题。 额济纳绿洲位于黑河下游,是黑河流域面积最大的一处天然绿洲。在中游来水不断减小及全球变暖的影响下,绿洲温度上升、蒸发加剧、地下水位下降、植被退化、面积萎缩,生态恶化的趋势十分严重。本文对黑河流域不同地貌部位(洪积扇、冲积扇和冲积平原)绿洲的熵产生进行了计算并加以比较,发现其值自下游向上游递减,这说明在自然状态下黑河流域绿洲的生产力自下游向上游递减。能值分析也表明这个绿洲具有很大的发展潜力,这与历史时期的生态环境格局相一致,但人类不合理的资源利用方式及战争等已改变了这一格局,致使额济纳绿洲不仅面临荒漠化迅速扩展及消亡的危险,而且成为全流域经济社会发展比较落后的地区。这一结论印证了黑河分水工程水资源配置措施的合理性,同时也说明重新调整全流域农林牧业布局的必要性,以使额济纳绿洲的生产潜力充分发挥出来。具体而言,应在外部水资源及深层地下水开发的支持下,绿洲内部要以生态恢复为核心改变不尽合理的生产与生活方式,充分利用绿洲生态系统的自我调节机制,实现自然控制。 总之,盖亚假说建立了生命与环境之间紧密联系且相互作用的纽带,而MEP假说则为描述非平衡开放系统提供了非常重要的新手段,因此MEP假说和盖亚式的系统思想对绿洲及流域等非平衡系统的持续发展有非常重要的指导意义。更多还原

【Abstract】 Under continuously changing environmental conditions, the earth’s surface layer still keeps habitable for most of the species. Gaia Hypothesis states that this is because the biota regulates the environment and keeps its major factors within a range that most species can tolerate, and earth can be seen as a geophysiological organism. At present it is difficult to test and prove this theory because of the limitations of temporal and spatial scales, so it becomes a very much debated hypothesis . The hypothesis of Maximum Entropy Production (MEP) states that open systems far from equilibrium tend towards states of maximum entropy production, for example, the mean-annual climate system of earth is in the state of MEP due to the heat transport from the equatorial area to the poles by atmospheric circulation and ocean currents. Although the two hypotheses suggest that systems bear obvious teleological intents, they are heuristic to the research of earth sciences and ecology, and have made many achievements in the practical studies. This paper gives a detailed analysis of the two hypotheses, including major viewpoints, evidences and tests, discussions, etc. Then the author uses the ideas from the two hypotheses to study the ecological restoration of Ejina Oasis located in the western part of the Inner Mongolia Autonomous Region.Ejina Oasis, situated in the lower reaches of Heihe River, is the largest natural oasis in the Heihe River Basin. With the discharge from upper and middle reaches decreasing from the 1950s on and the impacts of global warming, this oasis has experienced the intensification of evaporation and the sensitively rising of surface temperature, decline of groundwater level and severe vegetation degeneration, and desertification processes is devouring the oasis. Phenomena of oases shrinking accompanied with the shrinking of water systems from lower reaches to sources are very common in dryland. The entropy production of different oases is calculated in different channel sections of the Heihe River Basin, and it is found that the values decrease from the lower to the upper reaches, among which Ejina oasis is the highest, and emergy analysis also indicates its great更多还原