【作者】 郑忠明；

【导师】 周志翔；

【作者基本信息】 华中农业大学 ， 园林植物与观赏园艺， 2011， 博士

【摘要】 城市湿地具有重要的生态系统服务功能,然而城市化和基础设施建设等人类活动不断加剧,导致湿地景观面积萎缩,结构破碎,功能下降,严重影响区域可持续发展。湿地保护与恢复已成为当前区域生态可持续发展中所面临的重要问题。木研究在遥感和地理信息系统的支持下,研究了武汉市湿地资源的景观格局变化、湿地植物生物多样性特征,并分析了不同类型湿地资源的退化机制,重点研究了武汉市城市湿地资源的保护与恢复策略。主要结果如下：(1)武汉市城市湿地景观变化以1991-2007年四个时期的Landsat TM影像为基本数据,分析了城市化背景下武汉市湿地景观17年间的动态变化规律。结果表明,武汉市湿地景观逐年减少,平均年减少量为2751.42hm2,年下降率为1.38%。其中1991-1996年湿地景观的年变化率高于武汉市湿地景观近17年间的平均变化率,与建设用地面积相对应。研究时间范围内,自然湿地大量减少,人工湿地略有增加；湖泊湿地是武汉市湿地景观的主要类型,是湿地景观面积减少的直接因素；人工湿地的增加并未改变武汉市湿地面积下降的趋势；城市化进程的加快使得武汉市湿地景观表现出最大斑块占湿地景观面积比和分维数逐渐下降、破碎度升高的趋势。(2)武汉市湿地植物多样性特征武汉市城市湖泊湿生植物资源丰富,本研究共记录武汉市城市湖泊湿地维管束植物82科231属361种(含变种和变型),其中被了植物是主要类型。禾本科(G-ramineae)、菊科(Compositae)、豆科(Leguminosae)和莎草科(Cyperaceae)为优势科。各科在属水平上的分布则比较分散。武汉市湖泊湿地植物属的地理成分复杂,兼有地带性、隐域性和起源上部分古老性的特点,但特有属、种匮乏。其中蕨类植物种类较少,具有非常明显的隐域性特征；种子植物多样性较高,分属于14种地理分布类型,世界分布、泛热带分布和北温带分布3种类型占绝对优势,表现出明显的亚热带湿地植物区系特征。湿地植物生活型中以一年生和多年生草本居多。本文将水分做为武汉市湖泊湿地植物生态适应型的主导因子进行分类调查,结果显示,中生植物的种类(164种)位居首位,占所有种数的45.4%,表明武汉市湖泊湿地维管束植物群落的演替方向为中生植物群落。武汉地区湖泊湿地外来入侵物种普遍存在。外来入侵种包含在12科17属24种内,占全部外来物种(15科23属31种)的77.4%；剩余总数的22.6%基本都是人为引进栽培种。外来植物已经对武汉市湖泊湿地植物的生物多样性和生态系统稳定性构成了极大的威胁。(3)武汉市湿地生态系统退化特征与机制本文从武汉市23个典型城市湖泊湿地的生物退化特征、生境退化特征以及功能退化特征三方面来进行研究,运用综合聚类分析对获取的数据进行处理,重点调查的23个城市湖泊湿地依据退化程度的存在较大差异,可分为三大类,退化程度轻微的湖泊湿地有竹叶海湿地、严东湖湿地、北太子湖湿地、清潭湖湿地,退化程度中度的湖泊湿地有南太子湖湿地、野芷湖湿地、塔子湖湿地、黄家湖湿地、汤逊湖湿地、野湖湿地、青菱湖湿地、龙阳湖湿地、沙湖湿地、南湖湿地、张毕湖湿地、严西湖湿地、墨水湖湿地、北湖湿地、东湖湿地、五加湖湿地、三角湖湿地,退化程度中度的湖泊湿地有内沙湖湿地、紫阳湖。城市化是人类对湿地干扰的重要标志,主要表现为湖泊湿地外环境的土地利用方式的改变。农田的覆盖率和建设用地的覆盖率是退化程度不同的湖泊湿地之间最主要的差别,退化程度越高的湖泊湿地,湖泊周边建设用地覆盖率越高,农田覆盖率越低。退化原因主成分分析表明,围垦、侵占湖泊和外源污染是造成武汉市城市湖泊湿地退化的主要原因。(4)武汉市湖泊湿地分类保护模式所调查的26个湖泊湿地维管束植物的丰富度指数、多样性指数、生态优势度及均匀度指数具有类似的变化趋势,其中内沙湖和外沙湖各项指数最低,而位于郊区的严西湖和汤逊湖等均有较高的多样性,多样性指数存在空间上的差异性,地域性较为明显。湿地典型植物的优势度与丰富度有所差异,变化趋势大体相同,这与总体湿地植物物种丰富度及优势度的特征基本一致。严东湖湿地植物群落沿水分梯度的分布规律充分表明,季节性积水生境的各个群落多样性指标均高于其他生境群落。按照物种丰富度、多样性、优势度、均匀度、湿地植被群丛数目,以及典型湿地植物的物种所占比例、丰富度和优势度的差异,将调查涉及的26个典型湖泊湿地分为原生植被湖泊、次生植被湖泊、人工植被湖泊和退化植被湖泊4类。原生植被湖泊应建立相对严格的湿地保护区,优先保护原有湿地植被。次生植被湖泊最多,城市发展区内的次生植被湖泊应建立30-100m的植被缓冲带,促进植被自然恢复和发育；而农业区的次生植被湖泊应引导和规范湖泊周围的农业生产模式,以减少人类活动干扰。人工植被湖泊应通过建立城市湿地公园,人工促进植被的近自然恢复。而退化植被湖泊则应尽快采用生态工程法促进湿地植被生境改善,并积极开展近自然湿地植被重建与恢复。(5)武汉市典型湿地植物选择及恢复模式本文在对武汉市26个典型城市湖泊湿地高等植物调查的基础上,采用TWINS PAN分类与DCA排序相结合的方法分析了严东湖湿地植物群落的类型和结构,并确定将梁子湖(1998-2002)、东湖(1992-1993)和严东湖湿地植物群落作为武汉市湖泊湿地典型植物群落,指导武汉市湖泊湿地的植被恢复和重建。在武汉地区典型湿地植物其不同的应用价值评价的基础上,结合各湖泊湿地功能特征、环境状况,将所调查湖泊分为生态保护型、景观美化型、经济生产型和综合效益型四种类型分别探讨其恢复模式,并各选择一个典型湖泊,来作为武汉地区典型湿地恢复模式营建的基础场地,以现有的植物群落为基础,提出其湿地植物恢复基本模式,为武汉市湿地生态系统的保护与恢复提供了依据。更多还原

【Abstract】 Urban wetland has important functions of ecosystem service. However, human activities such as urbanization and infrastructure construction, lead to shrinkage of wetland in area, structural fragmentation and functional decline. Wetland protection and restoration thus become an important issue in the region ecological sustainable development. With supporting of remote sensing and geographic information systems, this paper study the changes of landscape pattern, plant biological diversity and degradation mechanism of urban wetlands in Wuhan. We also focused on the Wuhan city wetland protection and recovery strategy. The main results are shown as followed:(1) Changes of Wuhan urban wetland landscapeUsing the multi-temporal Landsat remote sense images during 1991-2007, this study analyzed the landscape changes of Wuhan wetlands under the background of urbanization in recent 17 years. During the whole study period, the wetlands of Wuhan decreased in area with a mean annual decreasing rate of 1.38%, and annual decrement of 2751.42hm2. In particular, the annual-decreasing rate of wetlands during 1991a-1996a was larger than the mean decreasing rate in 17 years, and was synchronous with the area increase of Wuhan built-up area. During the study period, the area of natural wetland decreased, while constructed wetland increased. As a major wetland type of Wuhan, the lake wetlands had the fasted decline in area, being a direct cause of the wetland area decreasing in Wuhan. The increased area of constructed wetland did not prevent the decreasing trend of total wetland area. With rapid urbanization, the wetland in Wuhan showed the trends of the largest patch index and fractal and connectivity decreased and the fragmentation increased.(2) Plant diversity feature of Wuhan wetlandPlant resources in Wuhan lake wetlands were very abundant and included 361 vascular plant species, belonging to 82 families and 231 genera, in which the main category was angiosperm. Moreover, Graminea, Compositae, Leguminosa, and Cyperaceae are dominant families.The geographical composition the vascular plants surveyed is complex and widely associated with other florae thus showing both transitional and anciently originated characteristics. However, the endemic species were very rare. The pteridophytes of lake wetlands in Wuhan were rare with obviously intrazonality. The seed plants were rich. Additionally, the 14 areal-types had a large proportion of the cosmopolitan, pantropic and north-temperate distribution types. It indicates obviously subtropical flora characteristics. The dominant life-form of wetland plants was perennial herbaceous and annual herbaceous. This article take moisture as dominant factor-based in the survey of ecological adaptation of wetland plants classification in Wuhan water lakes, the results of showed that the typical vascular plants (164 species) ranked first, accounting for 45.4% of all species. This indicated that the direction of the succession of plant communities living tubes plant of wetland lakes in Wuhan.In this paper, exotic plant survey results showed that the lakes in Wuhan have been around the alien invasive plants. Invasive species has 24 species (12 families,17 genera), accounting for 77.4%of alien species. The remaining 22.6%of the total are basically cultivated species by human. These exotic plants had been a great threaten to plants biological diversity of lake wetlands in Wuhan.(3) Ecosystems degradation feature and mechanism of Wuhan wetlandAccording to biological, habitat and functional features of 23 emblematical lake wetlands in Wuhan, we got a lot of data referring to ecosystems degradation, which were dealt with hierarchical cluster analysis. We divided the 23 lake wetlands into 3 classes with degradation degree. Zhuyehu Lake wetland, Yandonghu Lake wetland, Beitaizihu Lake wetland and Qingtanhu Lake wetland are contained to the first class(Degraded Slightly), Nantaizihu Lake wetland, Yezhihu Lake wetland, Tazihu Lake wetland, Huangjiahu Lake wetland, Yehu Lake wetland, Qinglinghu Lake wetland, Longyanghu Lake wetland, Shahu Lake wetland, Nanhu Lake wetland, Zhangbihu Lake wetland, Yanxihu Lake wetland, Moshuihu Lake wetland, Beihu Lake wetland, Donghu Lake wetland, Wujiahu Lake wetland, and Sanjiaohu Lake wetland are contained to the second class(Degraded), the third class is degraded seriously lakes, such as Neishahu Lake wetland and Ziyanghu Lake wetland.City construction is one of the most remarkable symbols of human’s effects to lake-wetlands. Urban construction affected the lake-wetlands by changing the land use type of environment around the lake-wetlands. The percent of construction coverage and agriculture coverage were the most remarkable differences among lakes of different degraded class. With the increasing of construction coverage percent and the decreasing of agriculture coverage percent, lake wetlands’degradation degree wound is increasingly serious. The results of degradation cause principal component analysis indicated that the primary degradation causes of lake wetlands were inning, breaking into and polluting the lake wetlands in Wuhan. (4) Classified protection mode of Wuhan lake wetlandThe change trends of species richness, plant diversity, ecological dominance, and evenness of vascular plants in lake wetlands in Wuhan are relative consistent. However, there were significant differences in plant diversity (abundance, diversity and evenness), association abundance and common wetland plants diversity (including percents of total common wetlands, abundance and dominance) among various fielded lakes. The spatial distribution of abundance of vegetation types, formation and association in different lakes are very consistent. Even though the vegetation communities are abundant in Donghu Lake, Yanxihu Lake, Qinglinghu Lake, Sanjiaohu Lake, Yandonghu Lake, and Chedunhu Lake, the majority of lakes still contain fewer plant community types. And the number of typical plant species had more obvious spatial variation.According to these characteristics, the lakes were classified into four classes, which included native vegetation lakes, secondary vegetation lakes, artificial vegetation lakes, and degraded vegetation lakes. In the native vegetation lakes, wetland natural reserves should be constructed so as to conserve the native wetland plants. The secondary vegetation lake is the most common type of lakes. Differentiated management measures should be developed according to their location. In urban area, vegetation buffer zones with the width of 30-100m should be considered to establish in order to promote restoration and development of wetland natural vegetations; while in agricultural areas, the government and managers should guide and regulate the mode of agricultural production around the lake to reduce disturbance of the human activities. Urban wetland parks should be constructed to protect the artificial vegetation lakes and promote the near-natural restoration of wetland vegetations. Some ecological engineering methods are also needed to improve wetland habitat of the degraded lakes as soon as possible, and then recover them with near-natural wetlands vegetation.The research of the Yandonghu Lake wetland plant communities along the moisture gradient demonstrated that the seasonal sweeper environment diversity index were all significantly higher than all other habitats community.As the lower of terrain, water increase, tree and shrub, mesophyte, mesophreatophyte, typical vascular plants of wetland plant, hydrophyte herbage plant seriatim appeared in particular space.(5) Typical wetland plants selection and recovery mode of Wuhan lake wetlandOn the basis of higher plants investigatation of 26 urban lake wetlands of Wuhan, summarize the Liangzi lake wetland and Donghu lake wetland historical plants situation changes by using TWINSPAN and DCA, analyze the type and structure of Yandonghu lake wetland higher plant communities, identified the Liangzihu(1998-2002), Donghu(1992-1993) and Yandonghu lakewetland plant as the reference target of Wuhan lake wetland vegetation restoration, guide Wuhan lake wetlands’restoration and reconstruction. Based on the evaluation of the Wuhan area typical wetland plants’ different application, combined with the wetland function characteristics, environmental conditions, investigated lakes were classified into four models:ecological protection model, landscaping model, economic productive model and comprehensive efficiency model and probed its recovery mode respectively, choose a typical lake from each mode as the basis site of Wuhan area, based on the existing communities, submit their basic mode of restoration of wetland plants. It gives a theory and data support of Wuhan wetland protection and rehabilitation.更多还原