【作者】 李首成；

【导师】 程序； Erle C. Ellis；

【作者基本信息】 中国农业大学 ， 作物栽培与耕作， 2005， 博士

【摘要】 本文利用获得的川中丘陵地区LANDSAT 7、IKONOS高分辨率(1m)卫星影像和GIS、GPS技术,通过乡村景观抽样,景观分类,景观制图,获得了较为精确的和完整的1945年和2002年两个不同历史时期的乡村景观类型构成信息。基于此,研究了四川盆地丘陵中部典型乡村景观构成和异质性特征及其长期变化,乡村景观生产力水平的长期变化以及碳、氮源汇功能的长期变化。主要研究结果如下。 一、随着人口的增加和人为活动影响的加剧,川中丘陵区乡村景观2002年比1945年发生了很大变化,改变强度为-91.60～231.23%。生态立地类型减少的有16个,新增的类型有22个。 二、川中丘陵地区乡村景观的异质性在不同景观分层上有较大变化,尤其是多样性指数、优势度指数和破碎度变化较大,均匀度、分形维数变化较小。多样性指数1.4667～2.4225;破碎度2.2286～4.9937。2002年与1945年比较,景观多样性指数增加了15.75～46.61%,破碎度指数提高了80.55～153.85%。 三、2002年乡村景观生物量平均每公顷32.41吨,较1945年提高了57.71%;景观生产力为27.46吨/ha,较1945年提高了138%。乡村景观生态系统有较弱的碳汇能力表现。3平方公里的样本区内,碳的固定量为291.33吨,即,每平方公里97.11吨。这一研究发现,对于国内外学术界长期争论的东南亚地区农田温室气体功能、全球“遗失”碳库等问题,提供了有价值的一手资料。景观内总N的平衡状况是输入大于输出。1945年,系统内净输入氮每公顷约0.08吨,2002年约0.56吨。2002年N素施用水平为484.48～1307.92kg/ha,其中化肥N施用量249.92～838.83kg/ha,超过了化肥N施用的安全线。氮素使用存在明显不合理部分,无效N投入比例达到了41.09%,成为乡村面源污染的重要源。 由于本项研究综合运用高分辨率(1m)卫星影像、地理信息系统和GPS技术,以及应用权威性的土地利用历史资料,乡村景观的分辨力较高,因此,研究结果的可信度高。同时,结合进行了典型村农产景观管理调查和老人历史访谈,实地研究乡村景观结构、分类和功能的长期变化和人为活动的影响,为研究村级以下小尺度农业景观生态系统提供了可资借鉴的方法,具有独创性。更多还原

【Abstract】 A village area, which located in the towns Yunhe, Youxin, Jintang county, and the town Tashui, Jiangyang county, about 100 km~2, was selected as the typical area of interest (AOI) for the research project of long-term biogeochemical change of anthropogenic village landscapes in the middle of Sichuan hilly basin region, using GIS and GPS technology with the base imagery of Landsat 7 and IKONOS. 12 village landscape cells, including 91% information of this region, were sampled in the AOI. In this project, we based on the high resolution (1m) IKONOS imagery in 2002 and the aerophotos of WW2 taken in 1945, have carried out household landscape survey, elder historical interview and groudtruth, established the multi-stratification village landscape classifying system: landform → landuse (land management) → landcover → ecotope (group+type),finished more precisely the ecotope mapping work. Following this, the landscape components and patterning, village landscape productivity, carbon and nitrogen source/sink, and their long-term changes between 1945 and 2002 have been studied. The main results as following:1. Great changes has taken place in village landscapes since 1945 with increasing of population and more strong effects of human activities. The anthropogenic units in landforms, such as house buildings, roads and reservoirs etc, in 2002, increased by 231.23% over 1945, but bench plateau , stream reduced 11.99% and 91.60% respectively. Some steep slopes and summit changed to bench plateau. For landuse, rainfed cropland reduced, but built-up and disturbed area increased by 480.17%. Perennial plant landcover increased by 186.57% over 1945 and sealed landcover by 386.09%. There were 16 kinds of ecotopes reduced, mainly cropland on bench plateau (BPRAac04), mixed open woody land on steep slope (SSTMow02), rice paddy submerged and fallow in winter (FSPAri03) and annual crop land on summit, significantly. The number of increased ecotope types is 27. Perennial evergreen needle leaf tree on steep slope (SSTPen03) increased by 335.52%, multi-story houses with shared wall or courtyard (ANCSho03) by 769.57%. Increased brand-new ecotope types are mainly rice paddy with double cropping season (FSPAriOl, BPPAri01), orange orchard (BPRPoe33,SLRAoe33), mixed crop land (BPRMmc01), bamboo on bench plateau (BPTPtg24) and planted evergreen needle leaf tree on steep slope (SSTPenOl).2. The heterogeneity of village landscapes in different stratifications has significant difference, and especially Shannon-Weiner indexes, dominance and fragmentation have changed greatly. The Shannon-Weiner indexes and the fragmentations of landform, landuse, landcover and ecotope are 1.4667, 2.2286; 1.3282, 2.4621; 1.1824, 2.8291; and 2.4225, 4.9937 respectively. Comparing the landscape indexes in 2002 with those in 1945, the Shannon-Weiner indexes increased by 15.75~46.61%, the evenness by 13.63~46.61%; the dominance reduced by 3.84~29.53; the relative richness changed from -6.67 to 78.95% and the fragmentation increased by 80.55~153.58%.3. In 2002, the biomass of village landscape is 32.41 t/ha, increased by 57.71% over 1945; thelandscape productivity 27.46 t/ha, increased by 138% over 1945. The village landscape system is performing as the carbon sink with the carbon fixation ability of 97.11 t/km~2, while in 1945, the village landscape did as carbon source with carbon release 49.76 t/ha. That carbon source in 1945 transformed to carbon sink today resulted largely from the carbon sink enhance of paddy, orchard, forestry and woody bushes, which compensated the carbon release of rainfed cropland as carbon source. This discovery offered the first-hand data for the long-term dispute about questions such as warming gas release in crop field in the Southeast Asia and "missing carbon sink". As far as nitrogen flux in the village landscape, the input has always been bigger than the output. In 1945, the net N input was 0.08 t/ha, and that in 2002 0.56 t/ha. Nitrogen applying amount in 2002 reached to 484.48~1307.92 kg/ha, the chemical fertilizer N,更多还原