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基于多源遥感数据的厦门城市森林景观格局研究

Study on Urban Forest Landscape Pattern Based on Multiple Date Sources in Xiamen

【作者】 高美蓉

【导师】 王成;

【作者基本信息】 中国林业科学研究院 , 生态学, 2013, 博士

【摘要】 城市是人类在改造和适应自然过程中,伴随着人类文明与进步发展起来的自然----经济----社会复合系统。在城市化的过程中,城市的土地利用发生着显著变化,它所带来的城市景观格局变化对城市生态系统产生着深刻的影响,也对城市生态系统中维护生态平衡的主体——城市森林产生着深刻影响。科学合理的评价及建设城市森林,对有效改善城市生态环境、促进可持续发展具有重要的理论和实践意义。厦门市是我国城市化发展最快的地区之一,在城市快速扩张的过程中,产生的景观生态问题在我国的城市化发展过程中也极具典型性和代表性。本论文选取厦门市作为研究区域,采用厦门市1995年、2000年和2008年1:10万土地利用图、厦门本岛2009年Quickbird卫星影像以及2008年厦门市1:1万基础地理信息等数据,在市域和厦门本岛两个尺度上对厦门市景观格局及城市森林景观格局进行了分析研究。市域尺度上研究了厦门市土地利用/土地覆盖及林地变化对厦门市景观格局、城市热岛效应以及可持续发展状态产生的生态影响,从可持续发展的角度分析了厦门市在城市化推进的过程中开展生态建设、扩大绿色空间的必要性。针对热点地区—厦门本岛,根据高分辨率卫星影像的目视解译,构建了基于树冠覆盖的城市森林基础数据,在对树冠覆盖进行功能和面积分类的基础上,进一步创新性地研究了厦门本岛城市森林树冠覆盖景观格局特征、梯度变化、树冠覆盖潜力、树冠覆盖与热岛效应的空间分布关系,研究在不能显著增加生态用地面积的条件下,如何通过潜在树冠覆盖来拓展生态空间。最后,针对厦门市城市森林优化建设提出了对策建议。研究结果显示:(1)厦门市景观格局的形成、空间分布和类型分异与自然环境地域分异密切相关,地形差异决定了厦门市景观空间格局大尺度的基本框架,而快速城市化导致厦门市景观结构发生了显著变化。1995—2008年间,建设用地面积的快速上升和农业用地的大幅减少使得厦门市由原来以农业用地为主的景观逐渐转变成以建设用地为主的城市景观,破碎化程度加大,多样性指数增加。景观格局变化主要表现为大量的农地转化成建设用地。厦门市城市化建设已经达到了一定水平,呈现以厦门本岛为核心的多中心景观格局。(2)厦门市林地资源较丰富,但在地域空间上分布很不均衡,89.9%的林地资源集中分布在北部和西北部山区,城市区域和平原区的林地仅占厦门市林地总面积的10.01%,城市区域森林资源明显不足。受快速城市化和土地利用变化影响,厦门市林地面积减少,林地覆盖总体呈缓慢下降趋势,景观破碎化程度增加,抗干扰能力减弱。林地面积减少的原因主要是城市扩张使林地转化成建设用地,林地生态系统出现了一定程度的功能退化。城市化进度的进一步加快,征占用林地面积的持续增加,使将来的厦门市林地资源存在较大的不确定性。(3)厦门市人均生态足迹和人均生态承载力均呈下降趋势,但厦门市生态需求仍是其自身生态系统可供应能力的7倍多,厦门市经济快速发展、人口快速增长,以及土地利用结构调整导致的生态承载力下降使厦门市处于生态不可持续状态。从可持续发展的角度出发,厦门市必须在城市化推进的过程中通过大力开展生态建设,扩大绿色空间,提高生态承载力,促进可持续发展。(4)厦门市全市以热场增强为主要特征,热场强度普遍提高,厦门市本岛和海湾区域热岛效应最严重。主要的热场类型以中等热岛和强热岛为主。植被盖度的降低和高植被覆盖度生态用地面积的减少是导致厦门市热岛效应增强的重要因素。加大城市绿化力度,增加植被盖度,提高绿地质量,才是缓解热岛效应的有效措施。(5)厦门本岛城市森林树冠覆盖率为25.71%,处于较高水平。树冠覆盖面积以大于1hm2的特大型斑块为主,数量以树冠覆盖面积0.01~0.05hm2的中小型斑块为主,道路和居住树冠覆盖破碎化程度高,公园树冠覆盖斑块数量最少但覆盖面积大,对维护厦门岛城市生态环境质量起着主导作用。厦门本岛有一定的树冠覆盖增长潜力,技术层面的潜在树冠覆盖率可达27.99%。潜在树冠覆盖以小型斑块为主,其中,以道路覆盖斑块潜在可增加数量最大。说明厦门岛道路现状覆盖虽然相对破碎,但未来形成连续覆盖的潜力最大。(6)厦门本岛城市森林树冠覆盖景观格局的形成、分布以及类型分异与自然环境的地域分异及城市森林建设理念密切相关,致使城市森林树冠覆盖空间分布的区域差异极为突出。厦门本岛公园树冠覆盖主要由城市化过程中保留下来的山地森林改造而成,是厦门岛城市森林景观中生物多样性维护以及生态服务功能的主要贡献类型。树冠覆盖景观的多样性和分维数指数偏低,城市森林的自然性和复杂性不够,在城市的南北轴向上,城市森林分布具有明显的梯度变化,呈现出斑块平均面积逐渐减小破碎化程度逐渐增高的梯度特征。梯度变化规律一方面反映了厦门市对位于厦门岛南侧的自然山地森林采取了较好的保护和利用措施。另一方面也反映了厦门市在城市用地紧张的现状下,人工建设的城市森林采取的是“见缝插针”的建设方式,建成的城市森林斑块面积小而分散,缺少一定量的较大规模的城市森林,严重制约了城市中心区域生态环境的改善和生态服务功能的发挥。厦门本岛地表覆盖类型与城市热岛效应分布区域呈现显著的相关性。公园树冠覆盖形成了较好的以公园绿地为中心的低温谷底,道路、居住区树冠覆盖及草地在降温作用显著的绿岛区域较少分布。尽管所有的植物都具有降温增湿、减缓热岛效应的生态效能,但规模小、破碎化程度高、植被盖度低的绿地缓解城市热岛效应的作用有限,只有绿化斑块体达到一定的规模才能有效减缓热岛效应。在未来的城市森林建设中,应坚持找地建绿和向树冠要绿并举的思路,在城市中心和北部区域结合城市改造适当规划建设较大面积的城市森林斑块,并努力提高城市森林植被盖度,提高绿量。城市化进程的推进对厦门市景观格局及城市森林景观格局产生了一定影响,随着海湾型城市建设的不断拓展,城市化将更深刻地影响着厦门市的生态环境。开展城市森林景观格局研究,对于今后厦门市进行科学的城市森林建设具有重要的理论和实践意义。

【Abstract】 City is a natural, economic,social complex systems with the transformation of humanbeings and the natural process of adaptation,along with the development of human civilizationand progress up. In the process of urbanization,urban land use is undergoing significantchange,it brings the urban landscape pattern change on urban ecosystems profound impact,but also exerting a profound impact on the urban forest which maintaining the ecologicalbalance in urban ecosystems subject. Scientific and reasonable evaluation and construction ofurban forests,to the effective improvement of urban ecological environment and promotesustainable development has important theoretical and practical significance.Xiamen is one of the fastest growing regions in the process of rapid expansion in China’surbanization,the landscape ecological problems in the development of China’s urbanizationprocess is also very typical and representative. Xiamen city was selected as the research area ofthe paper. Quickbird satellite images in2009and the TM images in1995,2000and2008,combined with fundamental geographic information(1:10000)in2008,were used to explorethe landscape pattern of urban forest in Xiamen city on two research scales,including Xiamenarea and Xiamen Island. On Xiamen area scale,the ecological impact that the changing of landuse/land cover and forest land on xiamen city to landscape pattern,urban heat island effect andsustainable development state were analyzed,the necessity in ecological construction andexpanding green space from the perspective of sustainable development of xiamen city in theprocess of urbanization as well. For hotspots----Xiamen Island,the fundamental data of urbanforest was built based on tree-canopy cover derived from the Quickbird satellite images. Basedon the classification on canopy cover functional and area which according to the urban forestcanopy cover basic data,the canopy covered landscape pattern, gradient,potential canopycover and the spatial distribution of the heat island effect relationship were studied,as well ashow to expand ecological space through the potential. Finally,optimization construction countermeasures and Suggestions to the urban forest construction in Xiamen were put forward.The results showed:Xiamen city landscape pattern formation,spatial distribution and type of differentiationand the natural environment of regional differentiation was closely related to topographicaldifferences determine the Xiamen city landscape spatial pattern of large-scale basic framework,and rapid urbanization had led to Xiamen city landscape structure undergone significantchanges. From1995to2008,the rapid increase in the area of construction land and agriculturalland made a significant reduction from the original Xiamen city landscape dominated byagricultural land to construction land gradually transformed into a mainly urban landscape.Landscape pattern changed mainly as a large number of agricultural land into construction land.Xiamen urbanization had reached a certain level,urban construction presents to the core of theisland landscape,multi-center,was a typical urban landscape. Urbanization with the rapidincrease of construction land resulted the increasing of landscape fragmentation degree anddiversity index in Xiamen city.Xiamen woodland resources were abundant,but in the geographical space unevenlydistributed,89.9%of the forest resources were concentrated in the north and northwesternmountains. Urban areas and the plains area of woodland woodland Xiamen only10.01%of thetotal area of the city regional forest resources was clearly insufficient. Affected by rapidurbanization, Xiamen city,woodland area decreased,overall forest cover decreased slowly,forest fragmentation increases,reducing the landscape immunity. Woodland area reduction wasmainly due to urban sprawl into the forest land for construction,forest ecosystems,there was acertain degree of functional degradation. Accelerate the progress of urbanization,reclaimedforestland area continued to increase,forest resources in Xiamen city there is a big uncertaintyin the future.Xiamen city, the per capita ecological footprint and ecological capacity per capitadeclining,but still Xiamen ecological needed its own supply capacity of ecosystems to seventimes, Xiamen city, the rapid economic development, rapid population growth and land use structure adjustment resulted in the decline in the ecological carrying capacity of Xiamen cityin ecological unsustainable state. From the perspective of sustainable development,Xiamencity must urbanization process of ecological construction through the great efforts to expandgreen space, improve ecological capacity, promote sustainable development.Enhanced thermal field was the main characteristics in Xiamen city,Xiamen Island andthe Gulf region were the most serious heat island effect region. The main types of thermal fieldwere medium heat island and strong UHI based. Vegetation coverage reduction and highvegetation coverage ecological land area decreased was the main factor which led to the heatisland effect enhancing. Increase urban greening efforts to increase vegetation cover andimprove the quality of green spaces,was an effective measure to mitigate the heat island effect.Xiamen Island urban forest canopy coverage was25.71%, at a high level. Extra-sized patchwhich larger than1hm2was mostly composed of tree canopy cover area,and mainly number tothe tree canopy cover wrer small and medium sized patch which sized0.01~0.05hm2,canopy covered roads and residential with high degree of fragmentation,parks crown coverwhich being the least number of patches but the largest coverage area,was the dominant role inmaintenance on quality of urban ecological environment in Xiamen Island. Xiamen Island hadsome growth potential crown cover,the technical level of the potential crown cover was up to27.99%. Potential canopy covered with small patches dominated by which to increase the roadcovering the largest number of potential patch. Roadside tree canopy covere which withrelatively high fragmentation degree, will be the greatest potential for the formation ofcontinuous coverage in the future.Xiamen Island urban forest canopy covered landscape pattern formation, distribution,andtype of differentiation and the natural environment and the regional differentiation was closelyrelated to the concept of urban forest construction, resulting in urban forest canopy coverregional differences in the spatial distribution of extremely prominent. Xiamen Island Parkcanopy covered primarily by the process of urbanization preserved transformation frommountain forests was the mainly contribution type for maintenance of biodiversity and ecosystem services in Xiamen Island landscape. Canopy covered landscape diversity andfractal dimension index was lower,the naturalness and the complexity of the urban forest wasnot enough. Urban forest distribution had obvious gradient in the city’s north-south axis,showing a mean patch area decreases degree of fragmentation trend of gradually increasing.Gradient variation on the one hand reflected that good natural protection and utilizationmeasures was taked to the mountain forest which located on the south side of Xiamen Island. Italso reflected that the construction model of urban forest was a“must attack”constructionmethod under the shortage of land in the city of Xiamen,so the size of urban forest patch wassmaller and fragmented,be short of large-scale urban forest. It severely restricted ecologicalenvironment improvement and ecological service function in the urban centers. Park canopycover to form a good park green space as the center,with low-temperature trough, roadresidential canopy cover and grass in green island areas of the cooling effect was significantlyless distribution. Although all plants had cooling and humidification,slowing eco-efficiencyheat island effect, but the smaller sized and higher fragmented patch,with low vegetation covergreen alleviate the urban heat island effect was limited,only the larger green patch couldeffectively reduce the heat island effect. Urban forest construction in the future,we Shouldstick to find land to build green and creat more green from tree canopy crown,to built largerarea of urban forest patches in the city center and the northern regions combined with properplanning and construction of urban renewal,and efforts to improve the urban forest vegetationcover, increase the amount of green.With the advancement of urbanization of xiamen city landscape pattern and urban forestlandscape pattern has a certain influence,along with gulf-type city constant expansion of urbanconstruction,urbanization will be more profoundly affects the ecological environment ofxiamen city. Research on urban forest landscape pattern will be important theoretical andpractical significance to the scientific construction of urban forest in Xiamen city in the future.

  • 【分类号】S731.2;S771.8
  • 【被引频次】5
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