【作者】 杨俊平；

【导师】 孙保平；

【作者基本信息】 北京林业大学 ， 水土保持与荒漠化防治， 2006， 博士

【摘要】 库布齐沙漠在我国所有沙漠中的地理位置上处于最东端,该沙漠东西横跨干旱和半干旱两个自然地带,具有沙漠和沙地过渡的交错分布特性。特别是处于半干旱地带的部分沙漠具有典型性、特殊性和复杂性,深入研究其土地沙漠化形成过程、发生机理、景观动态、空间格局变化以及形成动因和综合防治技术等科学问题,不仅在理论上具有重要意义,而且在沙漠化治理实践中也具有指导性。本项研究采用野外调查、社会经济数据收集与室内分析相结合的路线。野外调查主要包括土壤与植被调查、土地利用现状调查和沙漠化治理模式调查,室内分析主要包括不同土壤、生物(藻菌类)样品的分析鉴定和遥感影像解译以及库布齐地区沙漠化动态、驱动机制、沙漠化治理优化模式等的综合分析。研究结果表明:(1)库布齐沙漠中东部地区土地沙漠化形成机制是自然和人为因素共同作用形成的。导致土地沙漠化形成的主要因素按重要次序依次为景观多样性>景观优势度>景观均匀度>景观分维数>农田开垦指数>牧压强度>人口密度。通过多因素建模综合分析发现在1995-2000年沙漠化扩展期,景观多样性、景观优势度、景观均匀度的贡献率分别为45.16%、33.28%和12.37%,三者累计贡献率达到90.81%。在2000-2003年沙漠化逆转期,景观多样性、景观优势度的贡献率分别为75.90%和14.52%,二者累计贡献率高达90.42%。(2)该区土地沙漠化从1987年到2003年之间呈下降趋势。从沙漠化土地形成的空间分布格局分析,沙漠化发生程度在空间上呈现出明显区域差异性和复杂性特点。空间分布格局虽具有变化性,但总体上呈缩小减轻态势。(3)在1995-2000年沙漠化扩展期,景观多样性指数、景观优势度指数、景观均匀度指数与沙漠化过程之间存在着较密切的函数关系,揭示了三者对沙漠化过程的作用机理和影响强度。景观分维数与沙漠化程度之间有较显著的幂函数关系。(4)在2000-2003年沙漠化逆转期,景观多样性指数、景观优势度指数、景观均匀度指数与沙漠化程度和过程关系都存有密切的函数关系。所不同的是景观优势度随沙漠化程度和过程的增加呈负相关下降的趋势。而景观均匀度指数随沙漠化程度和过程的增加呈正相关逐渐增加的趋势。(5)根据沙漠化形成动因,构建了包括微生物治沙在内的创新防治土地沙漠化系统对策框架体系。创建了三种典型治理模式,其中藻类治理模式、菌类治理模式及其更多还原

【Abstract】 Kubuqi Desert locates in the very east among all the deserts in our country. It spans arid and semiarid natural zones with the characteristic of the interlacing distribution of deserts and sandy land. In particular, some deserts located in the semiarid zone possess representative, particularity and complicacy. It is not only meaningful in theory but also instructive in the practices of desertification prevention to give deep researches on the formation process, mechanism, landscape dynamics, spatial pattern changes, driving factors of formation and integrated prevention technology of land desertification in this region.The study adopted the way of combining the field investigation, society economical data collection and indoor analysis. The field investigation mainly included: soil, vegetation, actuality of land use and patterns of desertification prevention. The indoor analysis mainly included: analysis and identification of the samples of different soils, microbe (homonemeae), interpretation of RS images and the integrated analysis of desertification dynamics, driving mechanism and optimum pattern of desertification prevention in Kubuqi desert area. The results indicated:(1) The driving mechanism of the formation of land desertification in the east part of Kubuqi Desert was resulted by the conjunct effects of natural and human factors. According to the importance, the orders of the main driving factors leading to the formation of desertification were: landscape diversity > landscape dominance > landscape evenness > landscape fractal dimension > cropland reclamation index > grazing capacity > population density. Depending on multi-factor modeling and integrated analysis, it was discovered that: during the expanding period (1995-2000) of desertification, the contributing ratio of landscape diversity, landscape dominance and landscape evenness were 45.16%、33.28% and 12.37% respectively,the cumulative contribution of the three were 90.81%; during the reversion period (2000-2003)of desertification, the contributing ratio of landscape diversity and landscape dominance were 75.90% and 14.52% respectively,the cumulative contribution of the two were 90.42%.(2) A downtrend of desertification was showed during 1978-2003 in study area. Taking the spatial distributing pattern of desertification formation for analysis, the occurrence degree of desertification showed obviously regional diversity and complicacy in spatial scale. Although the spatial distributing pattern was mutative, the desertification showed a reducing, alleviative trend as a whole.更多还原