【作者】 张玉虎；

【导师】 齐家国；

【作者基本信息】 新疆大学 ， 自然地理学， 2008， 博士

【摘要】 土地利用/覆被变化是全球环境变化的重要起因,由土地利用/覆被变化引起生态环境效应以及生态安全更是当前国内外研究的热点。北京门头沟区位于永定河流域的官厅山峡段和北京西山的核心区域,由于近几十年的土地利用变化衍生出一系列生态环境问题,借助“门头沟区生态修复研究与技术示范项目”的支持,选择永定河流域典型的生态环境脆弱区—门头沟区为研究对象,在LUCC、景观生态学、生态安全等交叉学科的基础上,开展了该区域土地利用/覆被时空演变特征、土地利用/覆被的景观生态学评价以及生态安全格局构建分析等内容的研究。研究结果能够揭示该区土地利用/覆被变化特征及其景观生态效应,基于生物保护的生态安全格局构建能够从区域景观尺度反映研究区的生态安全等级状态,研究结果在应用层面上能够为了解该地区LUCC演变特征以及开展生态恢复与可持续发展提供必要的科学依据与实践参考。论文以1984年、1991年、2001年、2005年的TM卫星影像等为主要数据源,在RS、GIS、GPS集成技术的支持下,运用LUCC分析模型和景观格局等多种模型方法,从不同角度对该区土地利用/覆被变化及其景观生态效应进行了定性、定量分析评价,揭示了土地利用/覆被的演变过程及规律,探讨性地利用景观生态安全格局理论与方法,构建了不同时期生态安全格局,通过景观栅格单元阻力值的界定划分了生态安全等级,并分析比较了生态安全状况的时空差异。全文主要由三部分内容共七章组成,第一部分(包括第一、二章):第一章综述了选题背景意义、相关学科理论方法以及研究目的内容、技术方案等。第二章阐述分析了研究区自然生态环境特征。第二部分(包括第三、四、五章内容,三章内容主要是遥感数据的处理、提取→土地利用/覆被变化→土地利用/覆被变化的景观生态评价):第三章数据的收集、野外考察以及研究区土地覆被遥感信息提取,利用多步骤分区分类法提高了山区遥感影像解译精度。第四章是基于多期遥感影像的基础上开展研究区土地利用/覆被变化时空演变研究,对土地利用/覆被变化的幅度、速度、程度、类型转化及空间分布趋势等进行定性、定量、定位的逐层深入分析。第五章是从景观生态学的视角分析评价了研究区土地利用/覆被景观格局特征及景观生态效应。第三部分(第六章):第六章利用景观生态安全格局理论构建了研究区生态安全格局,分析比较了研究区生态安全等级状态,提出了优先生态恢复治理低安全区域的建议。第七章是全文总结与讨论。本文得到的研究结果与结论:1.在以遥感影像为主要数据源开展土地利用/覆被变化研究中,在遥感数据处理方面,通过多种方法的比较,提出多步骤分区分类法比较适合研究区的实际,实验数据总精度达到77.58%,利用此方法为后续LUCC研究提供了精度保障。2.对研究区土地利用/覆被格局与过程的分析表明:过去二十一年间,该区的土地利用/覆被发生了比较剧烈的变化,在1984-2005年期间不同时间断面呈现波动变化,但总的趋势是:工矿、城镇用地面积呈明显增加趋势,耕地、水体、农村居民点、草地和其它用地呈减少趋势,而林地中阔叶林、灌木林呈增加趋势,混交林地与针叶林地减少,林地总体上是呈增加态势。在不同时间断面各地类具有不同的时空分布变化特征,①从数量变化上来看,1984-1991年,变化幅度从大到小依次是阔叶林地>灌木林>混交林>草地>针叶林地>耕地>农村居民点地>工矿用地>城镇用地>其它用地>水域;1991-2001年为草地>灌木林地>农村居民点>混交林地>针叶林>城镇用地>耕地>工矿用地>其它用地>水域;2001-2005年为农村居民点>灌木林地>针叶林>阔叶林>混交林地>城镇用地>工矿用地>草地>其它用地>水域>耕地。②变化方向和强度存在较大差异,不同时间断面发生情况各不相同,各地类有增有减,主要有持续增加型,先增后减型,先减后增型;三个时间断面的土地覆被变化速度、类型转化、以及土地利用程度发生变化,表征指标为单一土地利用平均动态度、单一土地利用平均转出率和转入率、综合土地利用动态度以及土地利用程度综合指数。③各地类土地覆被的垂直空间分布出现变化,从研究期1984-2005年间的绝对量看,决大多数地类的分布平均高程是相对增加,向高海拔区域发生转移,降幅最大为混交林,下降了66.75m。水体、工矿用地、耕地的平均分布高程趋向于高海拔地区。平均坡度下降的有农村居民点与针叶林,下降了0.58,1.99度,其余地类呈增加趋势。3.从景观生态学的视角分析了不同时断土地覆被景观格局的特征,在1984-2005年期间研究区整体景观格局的破碎化趋势减弱,期间出现波段变化。林地景观的景观基质作用明显,各林地类型之间景观指标出现波动,人工干扰景观工矿用地、城镇用地面积、比例增幅较大,期间斑块数、斑块密度总体上呈上升趋势,不同时间断面出现波动,水体整体面积、比例下降,破碎化趋势减弱,各类型景观斑块质心水平空间上发生了偏移,研究区土地覆被景观变化的相对生态价值指数从1984年的3710.27增加为2005年的3733.59,说明生态环境开始向好的方向发展。4.通过利用最小费用距离模型,以生物保护的生态安全为目的,建立不同时期(1984、1991、2005年)生态安全格局,能够分析比较研究区生态安全相对等级状态,从数量上得到研究区的生态安全等级面积比例。三个时期低安全区占全部研究区面积比例为9.49%、10.44%、9.30%,空间上生态安全程度西部山区明显好于东部平原,对生态安全级别低的关键位置,应当优先考虑实施生态恢复治理。通过对永定河流域门头沟区土地利用/覆被变化过程、景观生态学评价以及生态安全格局构建分析等方面的系统研究,在下述理论方法与实践方面取得进展。1.选择永定河流域典型区—门头沟区作为研究区,从土地利用/覆被变化格局、格局变化过程角度系统研究了该区21年来的土地利用/覆被演变,从景观生态学视角分析评价了景观格局(结构)及浓缩在格局指数上的景观生态效应,探讨性地利用景观生态安全格局理论方法,把土地覆被景观结构与水平生态控制过程相联系,构建了研究区的生态安全格局,划分出了相对生态安全等级。研究手段为认识和理解门头沟区LUCC及潜在的生态安全问题提供了一种新的途径。2.在山区土地覆被遥感信息提取上,利用多步骤分区分类法减少了地形因素的影响,提高了信息精度,为后续研究的精确性提供了保障。3.在研究土地利用/覆被变化过程及景观生态评价时中考虑到地形(高度、坡度)因素,应用空间变化指数(平均分布高程、平均分布坡度)分析了各地类的的垂直方向空间变化;通过计算各地类景观斑块分布质心(经纬度),分析了各地类景观斑块的水平方向变化趋势;利用景观生态价值指数(LEVI)测算了区域土地覆被景观格局的相对生态服务价值,从宏观角度初步反映了研究区土地利用/覆被变化的规律及景观生态效应。更多还原

【Abstract】 It is we11 known that LUCC(Land Use/Cover Change) is the current front and hot field of current global change study. It is an important cause that global environment changes, It has become the focus in the field of environmental research from home to abroad. Eco-environmental effects on land use/cover change will become a focus in this research field in the future. And regional ecological security has been paid more and more attention in ecological fragile areas. Mentougou watershed is the important region of Yongding River watershed in North China bio-diversity and ecological landscape reservation. It is very significant to research the change of land use and cover and its landscape ecological effects. Over the past few decades, land use changes there have brought forth a series of severe ecological and environmental problems, which directly threaten the sustainable development of local society and the ecological security, Employing several satellite images of Landsat-TM and the integrated techniques of RS, GIS, and GPS, the authors, taking Mentougou Basin as a case, studied the process and ecological effect of land use /cover changes since the beginning of 1984, and then established and evaluated its ecological Ecological Security Pattern based on land use types of 1984,1991,2005.The study results can provide necessary and helpful reference for sustainble development and ecological conservation.Applying the satellite images of Land sat-TM and the integrating techniques of RS, GIS, and GPS, the paper analyzes the processes and landscape ecological effects of land use /cover changes and constructs landscape ecological security pattern in the typical area of the Youngling River Basin from 1984-2005. The result shows that:1. Result indicated that the effect of organization of classification process is one of the important contents in land cover remote monitoring in mountain area, the iterative multi-stage classification approach was significantly (overall accuracy is 77.58%, Kappa value is 0.7194) better than the single-stage classification approach. And this organizational methodology for classification is feasible and reliable in the image classification of mountain area.2. Over the past 21 years, land covers in Mentougou Basin have experienced dramatic change.①In quantitative terms, from the year of 1984 to 1991, the absolute change extent obey the following sequence: broadleaved woodland >scrubland>mixed woodland >grassland> conifer woodland>cultivated land> rural residential land >Industrial- mineral land >Urban land>others land>water area; from 1991 to 2001,grass land> shrub woodland > rural residential land > mixed woodland > conifer woodland > Urban land > cultivated land > Industrial- mineral land > broadleaved woodland >others land > water area;and from 2001 to 2005, rural residential land > shrub woodland > conifer woodland > broadleaved woodland > mixed woodland > urban land > industrial- mineral land > grass land > others land > water area > cultivated land。②There is difference in direction and intensity of land cover. The over forest woodland kept on expanding over the past 21 years , the cultivated land decreased in 1984,1991 and 2001 and then increased after 2001,the percentage of it in the study area is respectively 4.20%, 3.09%, 1.91% and 2.06%; The industrial- mineral land and urban land experienced an obvious increase, the percentage of which in the study area increased from (1.99%,0.8%) to( 2.74%,3.23&)in 1984 and 2005. Other lands experienced considerable decrease in 1984 and 1991, but increase after 2001. From the year of 1984 through 2005, The area of water area increased from 1984 (0.7% )to 1991(0.77% )and decreased in 2001,2005, respectively, the percentage of it in the whole study area is 0.24%, 0.45%.Meanwhile, land-use/cover change (LUCC) models have been playing process and quantitatively analyzing the status and the dynamic change of land use degree in research area. The land use/cover spatial pattern of each type was also very different. Index of average elevation and average gradient of land cover type were calculated, spatial distribution characters of each land cover type was analyzed in study area from 1984 to 2005.3. Based on the GIS and landscape indices model,ecological environment effect that the regional land cover change produced in study period was analyzed with landscape metrics on both class and landscape level from 1984 to 2005. On the whole landscape, there was a decrease in the patch number from 1988 to 2005,the patch number decreased from 35350 in 1984 to 25413 in 2005. The who1e shape turned regular and the fragment trend of the landscape degree became weaken from 1984 to 2005. Forest and shrub types are the main components of the present vegetation in the study area. The area of different landscape elements was very uneven. There were a decrease of the patch number and patch density to the total area. The patch number and patch density of industrial- mineral land and urban land increased obviously. The center of gravity of the each class landscape occurred distinct spatial movement in different study periods; the landscape ecological Value Index (LEVI) of the whole study area grown upon from 3710.27 to 3733.59,and the general eco-environmental quality tended to be better.4. Applying landscape ecological theory and effective cost distance model (EDM) constructed landscape ecological security pattern, which can realize the actual conditions of ecological security during different periods for case study. The temporal and spatial change of the ecological security caused the change of landscape structure during the period from 1984 to 2005. The distribution of ecological security rank is the obviously highest in the western mountain area and the lowest in east plain. The percentage of low security area in the study area is respectively 9.49%、10.44% and 9.30% in 1984,1991 and 2005; Finally, according to the present ecological security state, low security region should firstly be restored.By making a systematic study on the pattern and processed, ecological assessment of land use/cover change, also establishing and evaluating its ecological Ecological Security Pattern in Mentougou Basin, the author have made the following progresses:1.Taking Mentougou Basin in typical area of Yongding River watershed as example, the author systematically studied he processes and landscape ecological effects of land use /cover changes and constructed landscape ecological security pattern over the past 21 years, which fills up the gap of LUCC regional cases in Mentougou areas, and provided a kind of new approach for understanding and solving such challenging ecological and environmental problems.2. New methods have been proposed in this paper to improve the classification accuracy in addition to unsupevised and supervised classification procedures. the iterative multi-stage classification decreased influence of terrain. The gross classification accuracy of these new methods is 77.58 %, which is higher than the common unsupevised and supervised classification method. And this organizational methodology for classification is feasible and reliable in mountain area image classification.3. Landform factors influence land cover and its spatial distribution obviously. Index of average elevation and index of average gradient of land cover type were calculated and analysised. The center of gravity of the each class landscape occurred distinct spatial movement in different study periods. Study demonstrates that the LEVI put forward in the paper can well describe the ecological effect of land cover change on regional scale,which makes the index systems more perfect.更多还原