土地利用变化的解释

Explanation of Land Use Changes

用途转移和集约度变化构成土地利用变化的两种基本类型。土地特性自身的变化、土地使用者个体经济行为分析及社会群体土地管理行为分析 ,构成土地利用变化解释的理论框架。从土地特性考察 ,多宜性和限制性是土地利用发生变化的基本条件。人类对土地利用的结果 ,总是趋向于使土地的多宜性降低和功能类型减少。竞租曲线、转移边际点以及打破土地利用空间均衡的条件分析 ,是土地利用变化经济分析的理论基础 ;“土地利用 -环境效应 -体制响应”反馈环的作用机制 ,构成社会群体土地管理行为分析的理论框架。土地利用变化的机理模型 ,目前主要以新古典经济学和地租理论为基础。多视角的探索可能是土地利用变化机理综合分析的有效途径。

The most fundamental obstacle to progress in the understanding and prediction of human impacts on environmental changes lies in the lack of a comprehensive and integrative theory of human land relationships. The recent growth of research into land use and land cover change has revealed the inadequacy of current theories. On the other hand, specific land use issues have been effectively addressed by different disciplines, such as economic geography, regional and urban economics, and law. This paper reviews the land use theories and system models that indirectly or exclusively touch the dynamics of land use in time and space. A comprehensive framework for the explanation of land use changes is proposed. The author argues that a multi disciplinary approach into land use change studies, as an alternative to a new integrative theory of human land relationships, help the establishment of a holistic understanding of the process. Analyses of land user's economic behavior and land manager's institutional behavior constitute the major components of the framework. Thunen and Alonso's bid rent curve approach provides a foundation for the former analysis, while Platt's interaction loop among land use system, environment system and institution system provides theoretical base for the latter. With the bid rent curve approach, understanding of land use change lies in an analysis of conditions for change of transference margins in the micro perspective and an analysis of conditions for change of the slope of bid rent curve in the macro perspective. All these changes will break the spatial equilibrium of land use and then constitute the driving forces of land use change. With Platt's interaction loop approach, attention should be paid to strength of the signals from both the nature side and the society side. The author claims that changes on land use policies in China after the 'who will feed China' debate in the mid 1990s, the large flooding on the lower reaches of the Yangtze River and the strong dust storms in North China in early 2000, reflect the impact of strong signals. The paper also discusses the intrinsic properties of land that make unique of the dynamic mechanism of land use. Of these properties, multiple suitability, constraint in area and quality, and immovability are imperative to land use changes. Trend in land use specialization and the implicative shrinking of land's natural functions is a cue for the understanding of land use changes, and that of the overall human environment relationships as well.