【作者】 徐霞；

【导师】 何丙辉；

【作者基本信息】 西南农业大学 ， 水土保持与荒漠化防治， 2004， 硕士

【摘要】 恢复生态学与生物多样性和全球气候变化并列为生物领域的三大研究热点，它主要研究生态系统退化的原因、退化生态系统恢复和重建的技术与方法、生态学过程与机理的科学，是现代生态学的年轻分支之一，其研究对象是一些在自然灾变和人类活动压力下受到破坏的生态系统。结合水土保持生态环境建设已取得的研究成果与推广效应，充分发挥生态的修复能力，大面积迅速恢复植被和改善生态系统，正是顺应时代要求，从根本上解决我国水土流失防治步伐缓慢这一重大问题的最为有效的途径。重庆市巫溪县、璧山县是水利部和长江水利委员会水土保持局选定的“水土保持生态修复试点工程”试点县。巫溪县地处典型生态脆弱带——长江三峡库区内，属于全国生态环境建设重点地区，也是国家级贫困县。本论文依托巫溪县水土保持生态修复项目，运用模糊层次分析方法，进行退化生态系统的景观健康评价体系设计与健康等级分析；通过对比研究巫溪县与另一个生态修复试点县——璧山县的土地景观空间格局分析，揭示巫溪县土地利用格局上的退化特征；提出与水土保持治理相结合起来的生态恢复模式；引用土壤肥力质量指数，对生态修复区不同生态恢复演替阶段群落及不同时期坡改梯、休耕地与封山育林三项生态修复措施的土壤肥力质量分析与对比。研究结果主要包括： (1)巫溪县生态退化特征表现：作为生物生长基质的部分土壤薄而贫瘠，保水保肥能力差，部分地区基岩裸露，土壤的不断退化导致植物种多样性减少，植物种群结构逐步由复杂趋向简单化；县内水土流失的类型主要包括面蚀和沟蚀两大类，据调查，面蚀面积占侵蚀总面积的80％左右，其中坡耕地面蚀占耕地侵蚀面积的70％左右。 (2)巫溪县破碎度最大的为灌木林地，除居民点、裸岩石砾地、平原区水田与其它林地外，其余的破碎指数均高于1.7，表明这部分景观受人类干扰强烈，是主要的生态退化景观类型。巫溪县土地利用景观中，灌木林地为主要景观，且面积比重达到全县幅员面积的45.7％，西南农业大学硕士学位论文摘要目目..口....巨目.目巴.口草地面积也较大，其退化生态系统主要包括坡度>25。早地、山区早地、疏林地以及低、中覆盖度草地，也是水土流失主要的策源地;其水土流失的强度也表现出微度侵蚀占项目区的55%，中度侵蚀占23%，强度侵蚀占12%。巫溪县复杂的山地地势及受干扰的退化系统，形成了其斑块面积变异性大、形状不规则、破碎化程度高的景观特点，中度侵蚀是侵蚀强度与面积均大的侵蚀类型，且主要分布在受人类不合理开垦、滥砍滥伐活动的退化景观上。 (3)进行景观健康评价的结果表明，植被覆盖度对退化生态的景观健康评价贡献最大，其次是水土流失与恢复能力。生态退化最严重的是大于25。的早地，其次是山区旱地、山区水田，这说明了自然生态系统自我调节和抗干扰的能力较人工生态系统强，在生态修复工程设计中应侧重于依托于自然界的自我修复功能。运用模糊层次分析方法能将景观评价的定性与定量指标相结合起来，较好地分析出各指标对评价目标层的贡献大小的不同，综合分析各评价指标对景观生态健康的影响，同时也可对各具体评价指标进行对比，揭示影响目标层的单个指标特征。 (4)提出以下生态修复模式:封禁治理、草地改良措施、退耕还林措施、农田工程、农村能源工程。对不同生态恢复演替阶段群落的土壤肥力分析表现为:天然落叶阔叶林>林灌过渡>灌丛>草本>针阔混交林>针叶纯林。说明人工种植纯乔木种群并非是最好的生态修复措施，而以当地乡土树种为主要群落组成的天然落叶阔叶林、灌从及林灌棍合群落则表现出较好的土壤肥力条件，说明乡土树种更适合当地条件，更有利于群落的正向演替与恢复。不同生态修复措施间的土壤肥力分析结果表明:休耕地与封山育林均是通过自然恢复的时效期长的生态修复措施，但它们在对生态环境改善上却是长期有效的，并随时间推移其修复作用将愈加显著，相反，坡改梯工程措施作为三峡库区水土流失生态退化地域快速恢复的人为措施，还有其自身的局限性。更多还原

【Abstract】 Restoration Ecology is ranked as one of three hotpots in biological realm as well as biological diversity and global climate change in recent years, which is one fresh branch of Modem Ecology. Its primary research includes: the cause of degradation in ecosystem, techniques and methods of degraded ecosystem restoration and reconstruction, process and mechanism of ecology, research objectives of which are the destroyed ecosystems under the stress of natural catastrophes and human activities. The combination of obtained research achievement and extension effect in the ecological construction of soil and water conservation, sufficient exertion of ecological restoration ability, vegetation rehabilitation and ecosystem improvement widely and rapidly are the most effective approach to resolve the great problems on the slow steps of the prevention and cure of soil and water loss in China radically, which conform to the times. The Wuxi and Bishan county in Chongqing city is chosen as two of experimental units for "soil and water conservation of ecological restoration experimental project" by Ministry of Water Resources of People’s Republic of China and Soil and Water Conservation Bureau of Changjiang Water Resources Commission. Wuxi county is located in typically fragile ecological strip--Three Gorges Reservoir Area and belongs to national ecological environment construction key region. Based on soil and water conservation project in Wuxi county this article designs the landscape health assessment system and analyses health classes of degraded ecosystem by applying fuzzy AHP method, discloses degraded characteristics in aspect of land use patterns in Wuxi county contrasted with Bishan county, puts forward ecological restoration models combined with soil and water conservation harnessing, analyses and compares soil fertility quality in biological communities of different ecological restoration succession phases and restoration measures. The research results mainly show:(1) The ecological degradation characteristics of Wuxi county include: some soil is thin and barren and its water and fertility conservation abilities are poor, gradual degradation of soil results in decrease of vegetation diversity and the vegetation community structure gradually inclines tc simplicity from complexity. The types of soil and water loss in Wuxi county mainly involve surface erosion and gully erosion. According to investigation, surface erosion area occupies 80% or so orerosion area, in which the slope farmlands surface erosion area accounts for about 70% of farmland erosion area.(2)In aspects of land use landscape, Woodland has the maximum fragmentation value in Wuxi County. The fragmentation values of others except habitation, barren land, paddy field are all higher than 1.7, which means those landscape are disturbed fiercely by humans and are the primary parts of ecological degradation landscape. The woodland is the primary ecological degradation landscape and its area occupies 45.7% of the whole county area. The degraded ecosystems include: >25° dry land, mountain dry land, low density forest, grassland of low cover rate or moderate cover rate, all of which are the sources of soil and water loss. The low intensity of soil and water loss accounts for 55% of the project area, the moderate for 23%, and fierce for 12%. The complicated mountain topography and disturbed degradation ecosystem cause the landscape characteristics of high patch size coefficient of variance, anomalistic patch shape and high fragmentation degree. The moderate erosive intensity and area are both the greatest, which mostly distributed in the degraded landscape affected by human unreasonable activities.(3)The results of landscape health assessment indicate: vegetation bestow rate contributes to landscape health assessment most, while soil and water loss and restoration ability in the second place. The land use affected by degradation most is >25° dry land, while dry land and paddy fields of mountain area in the second place, which show that self-adjustm更多还原