人口变动、土地利用和环境变化关系研究

【作者】 王晗；

【导师】 侯甬坚；

【作者基本信息】 陕西师范大学 ， 历史地理学， 2008， 博士

【摘要】 伴随全球生态-环境问题的日益严重,人类生存环境的自然变化与因人类活动而引起的环境变化问题已受到国际学术界的普遍关注。而“土地利用/土地覆盖变化”(LUCC)研究作为全球环境变化科学关注的核心内容之一,是构建人类活动和环境变化之间的中心环节,是人地关系的集中体现。中国的黄土高原既保留着历时最长(约2200万年)、最完整的古气候记录,同时也是人类过去和正在居住的地球的陆地表面。区域内的环境变化过程虽然是几百万年来的地质现象,但在近万年尺度内尤为剧烈,这表明在此阶段,人类活动是引起黄土高原环境变化的主要因素,即人类对全球变化的影响更为重要。那么,历史时期人类活动对该区域环境变化有着哪些贡献?这些贡献又通过什么样的方式予以表达?同时,又应当用什么方式才能减轻?上述问题的着眼点正是本项研究所致力的方向。我们的研究以“人口变动、土地利用和环境变化的关系”为最终科学目标,立足于历史地理学,运用地貌学和人口统计学等相关的科学方法,选取陕北黄土高原典型地貌条件下的典型区域,将个案研究和宏观研究相结合,通过对发生在清至民国时期陕北黄土高原的重大历史事件进行复原,认真分析历史事件背后的自然要素,从中提取近300年研究尺度内与人口变动和土地利用有关的历史信息,做出相应的人口数据和土地数据关系的定量表达,探求人为因素影响下的土地利用变化和环境变化之间的关系,并进而总体把握此类研究对历史时期黄土高原环境变化的贡献。本项研究剖析了典型地貌区域(黄土塬区、黄土残塬沟壑区、丘陵沟壑区、风沙草滩区和典型流域)人为影响下的土地利用变化,分析了侵蚀环境中的人文因素,对土地利用过程中的政策、人口聚落变迁、耕作方式、生活习惯等方面进行了细致的探讨。通过研究,我们认为,历史时期黄土塬区的土壤侵蚀过程是人为加速侵蚀和自然侵蚀综合作用的结果,人为加速侵蚀的作用并不因为战乱和自然灾害的影响而有所减弱,在局部地区还存有加重的趋势。对陕北黄土高原土地利用政策的研究,有助于探究人类行为对环境施加影响的具体途径和可能达到的程度。对黄土高原沟壑区和黄土丘陵沟壑区在人口压力下的土地利用变化的研究,认为人口压力的增强、土地利用方式的固化和延续推动民众的耕垦区域开始发生变化,在高原沟壑区,土地利用的部位呈现塬面→梁地→坡地(山地)的发展态势;在丘陵沟壑区,土地利用的部位呈现由坡地→梁顶和沟掌地→梁峁斜坡和沟缘缓坡→地形陡、土层薄并有基岩出露陡坡或裸岩薄土部位的发展态势。土壤侵蚀随耕作部位的垂直性变化而逐步加强。通过对研究区内人口规模、人口密度、土地利用规模和强度的分析,我们认为,研究区内人口规模呈现自南部塬区→北部丘陵沟壑区→长城沿线风沙草滩区逐渐递减的趋势,人口密度则呈现由葭州、绥德州向外延伸的半扇形递减趋势。土地利用的规模和人口规模呈正相关关系,土地利用强度和人口密度呈正相关关系,而土壤侵蚀量的变化在时间上与人口的变化是正比关系,在空间分布上主要是受地理环境中的自然侵蚀和人为加速侵蚀的双重影响。综上所述,清至民国时期陕北黄土高原由于区域气候的特殊性,降水、霜期等自然因素的季节变化和区域变化明显,在人为影响下的土地利用过程中,土壤侵蚀问题突出。陕北长城沿线风沙草滩区随着农牧业开发而逐步增强,沙漠化在整个清时代呈现出一个较为平缓的变化趋势,而这种变化趋势直到民国时期才出现较为显著的变化。更多还原

【Abstract】 With the demand of globe ecological environmental problems increasingly serious, the natural changes of human living environment and the evolutions of environment changes under human activities were more and more paid attention to. The research of Land Use/Land Change (LUCC) ,as one of the core topics about the study of global environmental changes, is also an multidisciplinary topic popularly. China loess plateau had the longest time and most complete paleo-climate record, simultaneous it’s the residential land surface in past and present. The regional environment changes became extremely strenuous since 10,000 years. The fact shows that human activities are the main cause of the environment changes of loess plateau. Which contributions human activities act on the environment changes in historical times? How to expressed these contributions? How to alleviate them? Focuses of these problems are our research directions.The research objective is the relationship between population change and land use, and environmental change. This thesis has made full use of the historical geography, the geomorphology, the demography, selected classical areas of the loess plateau and analyzed important humane and natural events from the Qing dynasty to the Minguo period. Simultaneous the paper extracted historical information to study the quantitative expression of population data and land data. Finally this thesis searched for the relationship between land use and environmental changes.This thesis analyzed land use changes of the typical landforms (loess plateau gully region, loess gulled-hilly area, loess hilly and gully region, wind sand grass shoal area and typical basin) and studied humanistic factors (policies, habitation transformation, tillage management, living habits) . The study considered that historic soil erosion in loess plateau gully region is the combined effects of natural erosion and man-made accelerated erosion. Man-made accelerated erosion is not decreased in war disasters and natural calamities. Simultaneous the paper thought that population pressure, production pattern and cultivation region are the main aspects of land use changes in loess plateau gully region, loess gulled-hilly area, loess hilly and gully region. Soil erosion became more and more serious with the steeper cultivation positions from slope land to beam top. In addition, by the analysis of population scale, population density and land utilizing scale, the study thought that the population scale showed decreasing tendency from loess plateau gully region, loess hilly and gully region to wind sand grass shoal area and population density showed semi-sector decreasing tendency Jiazhou and Suidezhou-centered. Land utilizing scale had positive correlation with population scale and land use intensity had positive correlation with population density. Soil erosion had positive correlation with population changes in time domain and natural erosion and man-made accelerated erosion had double effects on soil erosion in space.To sum up, the seasonal changes and regional changes of natural factors in northern of shaanxi loess plateau were significantly for regional climate. In the land utilization procedure, the problem of soil erosion was very outstanding. The degree of environmental destruction was not remarkable before The Republic of China period.更多还原