【作者】 帅红；

【导师】 刘春平；

【作者基本信息】 湖南师范大学 ， 自然地理学， 2012， 博士

【摘要】 维持湖泊健康生命,实现人水和谐,是我国新时期的治湖理念。如何根据湖泊实际状况,构建合理的评价指标体系和标准,评价湖泊健康状况及其影响因素,是当前国内外湖泊科学研究的热点之一。洞庭湖为我国第二大淡水湖,接纳“四水”,吞吐长江,它不仅具有调蓄长江洪水,维持区域生物多样性,缓冲重金属污染、调节局地气候等多种自然生态功能,而且还是重要的粮、棉、油生产基地,更是重要的湿地资源。随着洞庭湖堵支并流、围湖造田、兴修防洪大堤以及第一期,第二期治湖(含退田还湖工程)工程建设和长江三峡工程蓄水运行,洞庭湖区资源环境现状受到了较大影响。本项工作从自然—社会经济复合系统出发,探究湖泊健康的概念与内涵。从形态结构健康、生态系统健康、服务功能健康、整体健康等方面,评价典型年东、南、西洞庭湖健康状况的时空动态变化,探求影响洞庭湖健康状况的因素,从而为湖泊环境整治和资源开发利用提供科学依据。水质与水生生物状况是评价湖泊健康状况的重要指标。本文首先借助BP网络、内梅罗指数以及综合污染指数等集成方法探究洞庭湖水质时空变化；采用综合营养状态指数,分析洞庭湖富营养化水平。结果表明：东洞庭湖水质劣于南洞庭湖,南洞庭湖劣于西洞庭湖；平水期水质优于丰水期,丰水期优于枯水期；东洞庭湖近年来出现了轻度富营养,而南洞庭湖、西洞庭湖为中营养状态。最后,采用Shannon-Weaver多样性指数揭示了水生生物在各湖泊的分布特征。硅藻门和隐藻门是东、南洞庭湖浮游植物的优势种群,而西洞庭湖的优势种群是硅藻门、隐藻门、绿藻门；浮游植物的数量、种属、多样性呈波动上升趋势；东、南、西洞庭湖底栖动物种群结构,基本都以软体类、水生昆虫、寡毛类为其优势种；其种类、种群密度和多样性指数呈波动下降的趋势,变幅最大的为东洞庭湖。形态结构是湖泊健康状况的重要表征之一。本文基于突变级数模型对洞庭湖形态结构健康水平的评价结果表明：洞庭湖健康状况年际变化以2004年为转折点,1986年和1991年东、南、西洞庭湖均为临界健康,1998年洞庭湖区各湖泊健康状况明显恶化。而2004年其健康水平得到了显著改善,为较健康；2006年和2010年东洞庭湖仍保持着较健康状态,而西、南洞庭湖健康状况为临界健康。生态系统状况也是湖泊健康评价的重要指标。本文利用加速遗传算法的投影寻踪模型,在Matlab7.0支撑下评价洞庭湖生态系统健康状况。结果表明,从1986年至2010年,其样本投影值呈现出波动式下降,这表明洞庭湖生态系统健康状况总体上有变差的趋势；其中,南洞庭湖生态系统健康水平相对最高,东洞庭湖最差,西洞庭湖则介于两者之间。根据最佳投影方向各分量的大小,可知水动力状况、生态需水量、有钉螺面积、水生生物多样性等指标的大小是决定洞庭湖生态系统健康状况好坏的关键性指标。服务功能是湖泊健康生命活力的象征,也是湖泊健康评价的重要指标。通过湖泊生态服务价值的估算,对洞庭湖健康水平的评价结果表明：从1986年到2010年,洞庭湖湖泊健康状况有所好转；东洞庭湖健康状况最佳,其次是南洞庭湖,西洞庭湖健康状况较差。洞庭湖整体健康是建立在湖泊形态结构、生态系统、服务功能均健康的基础上的。在上述各项指标评价的基础上,本文利用“PSR”框架模型,构建洞庭湖整体健康综合评价指标体系,利用主成分分析法和模糊评判法,评价洞庭湖健康特征。结果表明,健康状态总体较好的是南洞庭湖,其次是东洞庭湖,较差的是西洞庭湖。临界健康年份(1991、2004、2006和2010年)所占比重较大,为66.67%,不健康年份(1986和1998年)所占比重为33.33%,无健康年份；影响洞庭湖整体健康的指标主要是湖泊单位容积工、农业产值负荷、生态需水量、景观破碎度以及有钉螺面积等。通过本研究,可知三峡工程蓄水运行对洞庭湖健康状态的积极影响大于消极影响,表明该工程有利于洞庭湖整体健康水平的提升。本文为湖泊问题的研究提供了新思路,并拓展了视野,研究结果对于维护洞庭湖生态健康具有一定的实际意义,还为湖区社会经济发展的未来走向提供了科学依据。更多还原

【Abstract】 To maintain a healthy life for the Dongting Lake and to realize the harmony between humans and waters is the concept regarding China’s treatment of the Lake in this new era. It has become a hotspot in lakes’ researches both at home and abroad that how to construct a reasonable evaluation index system or standard and to explore the health status and those affecting factors on the basis of the actual conditions of our lakes.Dongting Lake, the second-largest fresh lake in China, is not only a natural storage place for flood of the Yangtze River, but also a chief treasure-house of keeping the biological diversity of the Yangtze River, and the most important is an prominent foundation for the development of the people living around the lake district. Nevertheless, its present environment has been greatly influenced, for those projects in Dongting Lake of blocking branches, converting lakes to farmland, building flood embankment, engineering the lake treatment constructions lasting for two phases and operating the impoundment of The-Three-Gorges project. This passage will quest into the concept and connotation of the lake’s health from the system combined with nature, society and economy, to diagnose the spatial-temporal dynamics changes in the health status of the lakes in typical years from the three aspects of structural characteristics, eco-system and service functions. In this way, those affecting factors can be found out so that the targeted treating work will be carried out on a scientific basis.Water environment and hydro-biological resources remain important indicators of lake health. At first, this passage explores the spatial-temporal variation on water quality of the Dongting Lake with the assistance of BP Neural Network, Nemerow Index and comprehensive pollution index. Second, the level of Dongting lake eutrophication is analyzed with the method of Comprehensive Trophic State Index.Results show that from the point of water quality, west Dongting Lake is the best, next is south Dongting Lake and east Dongting Lake, and in common water period water quality is the best, next is wet season and drought period; There is an upward trend in Dongting Lake nutrition level, especially in East Dongting Lake, there have been mild eutrophication in recent years, while south Dongting Lake and west Dongting Lake have reached the medium pollution level. And finally, the distribution of aquatic life in the Lake is revealed.The dominant species of phytoplankton in eastern and southern waters of Dongting Lake are diatoms and cryptophyta,while in western waters are diatoms, cryptophyta and green algae, the fluctuation in whose quantity, species, variety is on the rise; Software classes、aquatic insects and oligochaeta are dominant species of population structure of zoobenthos in east、south and west Dongting lake; The fluctuation in population density and diversity of species, is a downward trend, especially in East Dongting Lake waters.Morphology is the material base of formation and development of the Lake’s eco-system. Based on the catastrophe progression model, issues on morphological system health of Dongting Lake are explored. Results have shown us that:considering the interannual variability of the health status of the Eas、South and West Dongting Lake,2004is a turning point. In1986and1991, the conditions of the three lakes are all critical. And in1998, Dongting Lake’s health deteriorated significantly. But in2004significant improvements arouse in health on the whole, moreover in2006and2010East Dongting Lake still maintains a healthy state, while the healthy conditions of West、South Dongting Lake decline to a critical state.Eco-systems are important indicators reflecting health situation of Lakes. And in this passage, ecosystem health of Dongting Lake is evaluated based on the projection pursuit model of accelerating genetic algorithm. From1986to2010, Dongting Lake’s eco-system health sees a changeable decrease, reflecting its trend of worsening on the whole; The highest level of ecosystem health has achieved in South Dongting Lake, followed by the West Dongting Lake and the East Dongting Lake in a row. Depending on the component size by optimal projection vector, we can conclude that hydrodynamic conditions, ecological flow requirements, the area size of oncomelania hupensis and the diversity of hydrobios are all essential to the ecosystem health of the Dongting LakeEcological service function is the symbol of Lakes’ health and vitality. This passage goes on with the research on the health of Dongting Lake through estimation of ecological services value. We then come into the conclusion:from1986to2010, Dongting Lake’s health is improving; East Dongting Lake’s health is the best, followed by the South Dongting Lake and the West Dongting Lake.Overall health of Dongting Lake is on the basis of the lake’s morphology、eco-systems and service functions. In view of this, this passage constructs a comprehensive evaluation system of Dongting Lake health based on the "PSR" model and selects the ways of principal component analysis and fuzzy evaluation method to evaluate health status in the Dongting Lake. In general, the better is the South Dongting Lake, followed by the East Dongting Lake and the West Dongting Lake;In typical years, the year of critical health accounts for a large proportion-about66.67%, the unhealthy years for33.33%, without absolutely healthy years; The limiting factors affecting the overall health of Dongting Lake is mainly industrial and agricultural output load in each unit volume of the lake、 ecological flow requirement and landscape fragmentation, as well as indicators such as the area size of oncomelania hupensis.Through this study, the impoundment of The-Three-Gorges project operation on health states of Dongting Lake has more positive affect than negative, indicating that the project is conducive to raising the level of overall health of Dongting Lake.To sum up, this passage provides new ideas and new perspectives for study of lake-related problems, a scientific basis for the safety of flood control, water safety and ecological security of Dongting Lake, a possibility for sustainable economic and social development of the Lake District.更多还原