【作者】 王国新；

【导师】 魏美才；

【作者基本信息】 中南林业科技大学 ， 生态学， 2010， 博士

【摘要】 城市湿地是位于城市或城市边缘,被纳入城市景观和绿化系统的,能够为城市和城市居民提供多种生态服务功能的湿地区域,包括自然的河流、湖泊、池塘、沼泽、河漫滩、海滨以及各类人工水利和水景区域。城市湿地是一个“自然-社会-经济”复合生态系统,能够为城市居民提供多种重要的生态服务功能。但在我国近30年来城市化和工业化的高速发展中,城市湿地正在受到前所未有人类胁迫。城市不停地在侵入湿地,导致城市湿地消失,或遭到严重污染。前保留下来的城市湿地都是因为其能为城市提供独特的功能,其中以文化和风景名胜而被保留下来的居多。杭州的西湖和西溪就是两个典型的以历史文化和风景名胜而著名的城市湿地。它们也同样受到人类长期干扰和胁迫,其自然、社会、经济各方面都烙下了人类干扰的印记。今天,人类对城市湿地的干扰有增无减,城市湿地的未来完全取决于人类的科学保护和合理利用。由于城市湿地复合生态系统的复杂性,至今研究者甚少。但城市湿地和城市居民生活休戚相关,如果没有理论去指导城市科学保护和管理湿地,这些重要的城市生态资产可能就会很快消失,成为后人的遗憾。本研究以杭州市的西湖和西溪作为研究对象,通过查阅历史文献、制图对比分析、实地调研和访谈等手段,对这两个城市湿地的历史变迁进行了辨析,对近30年复合生态系统结构的变化进行测度。测度的要素包括：湿地形态、水文特征、水环境、植被类型、文明斑块(包括：建筑、道路、城镇、农田和园林等),以及社会、经济和文化要素。分析和辨识了造成西湖和西溪城市湿地变迁的驱动力及其驱动机制。在此基础上,对这两个城市湿地的生态服务功能的价值进行了评估和比较。本研究在方法上是一个多学科的尝试。试图将社会学和自然科学研究方法结合起来。通过历史解读、现状调查、数据和图形对比等方法来测度城市湿地自然、社会和经济等要素变化的速度、幅度和趋势。同时,还探讨了城市湿地生态服务功能评价的方法,提出了采用“房地产溢价法”来评估其改善人居环境功能的价值,采用“旅行费用法”和“条件价值法”评价了两个湿地的文化服务功能的价值,并对两者的价值构成进行了比较。研究结果得出如下结论：1.城市湿地是·个复合生态系统,由于长期受到人类的干扰,其生态系统结构与自然湿地有明显的差异。城市湿地的生态系统结构、生态过程和生态服务功能都主要由人类控制；2.杭州西湖自古以来因为其为杭州城市在不同时期提供了不可替代的生态服务功能,而得到杭州人民不断地疏浚和治理,才得以保留至今。改革开放以来,杭州进一步强化了对西湖的保护和治理,与1978年相比,西湖平均水深增加了0.5m,水域面积增加了0.66km2。通过钱塘江引水冲灌,西湖水质也基本控制在Ⅳ类水的标准。但城市扩展和旅游业发展对西湖水质和生态环境的负面影响也非常明显。虽然城市污水已经全部截流不再排入湖区,但城市径流和旅游活动导致西湖水质不断恶化,已经无法依靠自净能力维持,而需要依靠人工引水冲灌。水量平衡计算结果显示,每年引水12000万m3,是流域径流量的14倍多。由于西湖早在1982年就被国务院批准为国家级风景名胜区,西湖植被得到了很好的保护。但随着城市化和工业化的过程,西湖湿地流域范围内道路等基础设施和服务设施增加,旅游和休闲经济活动增强,导致景观破碎化、森林受损、生态系统健康状况下降。林地总面积几乎没有减少,但破碎度提高36%；由于道路拓宽,硬质路面占地面积增加了84%；虽然西湖湿地内居民不断迁出,但旅游设施建设导致建筑斑块总面积增加了3%,斑块数量增加了一倍,说明建筑占地总面积得到严格控制,并趋向分散布局。园林斑块也增加了26%,表明自然林地不断被改造成游憩园林。30年来,西湖湿地社会经济形态表现为居住功能弱化,旅游服务功能强化；经济表现为农业稳定、工业减少、服务业不断增加；西湖文化的建设和修复也得到前所未有的重视。3.西溪湿地由于长期没有得到有效保护,最终沦落为以水产和生猪养殖为产业的农耕湿地,城镇化和农业生产导致水质严重污染。原有的芦苇等优势水生植物群落基本丧失,鹭、鸥等大型水鸟不见踪影。城市扩张是导致西溪湿地面积缩小的主要原因。30年间,湿地斑块数量从43个减少到24个；湿地水域面积从50多平方公里减少到18.06平方公里；而湿地公园的保护范围只有10.06平方公里,仅为30年前湿地范围的五分之西溪湿地流域内的建筑斑块、道路面积明显增多,景观破碎化严重。西溪湿地周边城市化和道路建设,已经使得西溪湿地成为一个生态孤岛。虽然保护区内生态修复良好,但周边水环境的恶化依然是威胁西溪湿地的主要因素。数据显示,西溪湿地面积减少了23.5%,目前受保护的湿地公园面积只有原湿地面积的1/5；由于西溪湿地流域没有得到保护而城市化加剧,流域径流量减少且污染严重,西溪主要依靠西湖排水获取水源,后者流量是前者的7倍。西溪湿地流域内城市化明显,30年来,建筑占地面积增加32.4%,道路面积增加了530%。西溪湿地社会、经济和文化的发展趋势变化与西湖类似,但其旅游服务业的规模还比较小。西溪湿地正在从一个农耕湿地向生态保育、休闲旅游和科普教育型湿地转变。4.城市居民对城市湿地的生态服务功能认知具有明显的时代性特征。人类对城市湿地生态服务功能的需要是决定他们如何干扰湿地的直接驱动力。对杭州西湖和西溪生态服务功能辨识结果表明,城市湿地的“产品功能”已经基本丧失,“调节功能”逐渐在下降,“文化功能(旅游和文化)”最受重视,“支持功能”中的“人居环境”功能最为重要,而“动植物栖息地”功能的受重视程度相对较低。5.在分析城市湿地生态服务功能的基础上,对西湖和西溪两个城市湿地的核心生态服务功能进行了选取,并对其价值进行了评估。结果表明：西湖每年为城市提供的生态服务价值为1778676.5万元；西溪为150521.1万元。从总值来看,西湖的生态系统服务价值要远大于西溪,前者是后者的11.8倍。但西湖的面积接近西溪的6倍。西湖的单位面积价值就只有西溪的两倍多。西湖和西溪的价值构成中,“改善人居功能”和“文化功能(旅游、文化)”两项之和占各自总价值的98.6%和94.8%。这说明城市湿地的生态服务价值是人类长期保护、建设和文化积淀的结果。更多还原

【Abstract】 Urban wetlands are those wetland areas within a city or suburban area which have been integrated into the urban landscape and green system and, are capable of providing various ecosystem service functions for the city, including natural Rivers, lakes, ponds, swamps, floodplains, coastlines and a variety of artificial irrigation and water-based landscape areas. An urban wetland is a "nature-society-economy" complex ecosystem and provides a variety of important ecological service functions for the city.But within the last 30 years of high-speed urbanization and industrialization, urban wetlands in China are found under unprecedented stress from mankind. The city keeps expanding into urban wetlands, causing their rapid loss and heavy pollution. Most of those wetlands preserved within cities are providing irreplaceable service functions for urban residents, of which culture and tourism are the two most common of all.The West Lake and Xixi Wetland are two typical urban wetlands famous for their historic heritage and tourist attractions. Same as others, they are also subject to long-term human interference and coercion, and trace of human impacts can be found in all their natural, social, and economic aspects. Today, human interference of urban wetlands is more increasing than not, making the destiny of urban wetlands entirely dependent on the scientific protection and wise use of human-beings.Studies of urban wetlands are rarely found for the complexity of their ecosystems. But urban wetlands are closely related with urban residents’everyday life. We will lose those precious heritages if we failed to well protect and manage them, leaving a great pity for our future generations.In this study, Hangzhou’s West Lake and Xixi Wetland are taken as cases for historical analysis of wetland changes by means of comparative study through historic data review, map overlapping, site inspection and deep conversation. Changes were measured in respect to geomorphology, hydrology, water environment, vegetation and such human input patches as buildings, roads, towns, fields and gardens, as well as social, cultural and economic elements. Drivers causing these changes were identified and their driving mechanism is analyzed. Based on the above results, values of West Lake and Xixi Wetland ecosystem services were assessed and compared.Multi-disciplined approach is taken to combine sociological and natural science methodologies in this study. Speed, scope and trend of changes are all measured for major natural, social and economic indicators with figures collected through historic data review, on-site investigation, data and image comparing. Methods of ecosystem function evaluation were explored as well. Methods of Travel Cost and Contingent Value were employed to assess the social and cultural ecosystem-service values of the two wetlands, and their value compositions were compared.Key findings of this study are summarized as bellow:1. An urban wetland is a complex ecosystem, and its ecosystem structure is distinctively different from natural wetlands for its long-term interference received from human-beings. Its ecosystem components, ecological process and ecosystem functions are all dominantly controlled by human-being.2. It is the irreplaceable ecological service functions West Lake provided at different ages that explain the existence of West Lake and the cares Hangzhou people gave it by constantly dredging and maintaining.In the last 30 years of Open-door and Reform policy, West Lake protection and maintenance were further strengthened. Its lake basin is 0.5 meter deeper, water area 0.66 km2 larger, and water quality is kept better than Class 4 until now.But the negative impacts are obvious from urban expansion and tourism development. Heavy pollutants from urban running water and tourism have destroyed the West Lake’s self-cleaning ability and it’s dependent on pumped water to dilute the polluted water, although the interception system enables no sewage water into the lake.Hydro-balance sheet shows 120 million cubic meters of water is pumped into West Lake every year,14 times of its precipitation supply.As one of the earliest State-level Scenic Areas, vegetation is well protected and reserved in West Lake. But with rapid urbanization and industrialization, construction of roads and service facilities with huge inflow of tourists have led to such problems as landscape fragmentation, forest damage and ecosystem deterioration.Total area of forest changed little, but fragmentation rate reached 36%; Construction of wide roads made hard-surface increased by 84%; although more and more residents have been moved out and buildings increased only 3% as a result of strict control, but number of building patches doubled, showing a trend of diversion. Garden patches increased by 26%, a fact that more forests have been transformed into leisure gardens. During the past 30 years, residential function is decreasing while tourism service is strengthened in West Lake. Economically, agriculture keeps steady, industry has decreased while service increased. Historic heritage and culture restoration and construction are never more emphasized.3. Xixi Wetland once was turned into an agricultural farmland for short of protection, and its water was heavily polluted with urbanization and agricultural production. Reed community and big water birds such as seagull and pelican were nowhere to be found any more.City expansion is the major cause of XiXi wetland loss. Wetland patches have decreased from 43 to 24 in 30 years. Wetland area decreased from over 50 km2 to 18.06 km2. The designated area reserved for Xixi Wetland Park is only 10.06 km2.Study shows building and road patches have greatly increased in Xixi watershed area. City expansion and road construction have made Xixi wetland into an isolated ecological island. Deterioration of surrounding water environment is the greatest threat to the ecological health of Xixi Wetland。Study shows Xixi Wetland has decreased by 23% in area and the protected area for Wetland Park is only one fifth of its original size. As a result of rapid urbanization in its watershed area, running water is now the major source of pollution and short in supply, Xixi Wetland is dependent on West Lake output as major source of water supply which is now 7 times of its watershed supply.Urbanization during the 30 years has caused a 32.4% increase of building area and 530% of road area. Social, economic and cultural changes resemble that of West Lake, but its tourism size is still a small part of its economy. Xixi Wetland is under the transformation from a farming wetland to one maintained for ecosystem service, leisure and tourism, and scientific education.4. Recognition of wetland ecosystem service function by urban residents is featured as closely time-related. Their needs of wetland ecosystem service are the direct drivers of their interference to wetland. The identification of ecosystem service functions of West Lake and Xixi proved that production function of the two urban wetlands has almost completely lost; regulating function is decreasing, too; cultural function is the most recognized, and residential environment improvement as a supporting function for human-being is the most important and wild-life habitation function is the least recognized.5. Based on the analysis of wetland ecosystem service functions, core functions for West Lake and Xixi wetlands have been identified, and then used for the assessment of their ecosystem services. Results show that West Lake has a total of 17.8 billion RMB as ecosystem service value every year, while Xixi has only 1.5 billion RMB. Considered in total value, West Lake is 11.8 times of Xixi’s, far more valuable, but if divided by area, the former is only twice of the later.Among the four ecosystem functions, for West Lake, supporting function value is 98.6% of the total, while for Xixi, Cultural function 94.8% of the total. That explains that the ecosystem value of urban wetland is the long-term result of protection and cultural accumulation.更多还原