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Agricultural land use change in relation to agroecosystem health.

机译：与农业生态系统健康有关的农业土地利用变化。

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摘要

This thesis develops and tests a conceptual framework for assessing the changes in agroecosystem health from the perspective of agricultural land use.;To understand the dynamic relationships in agroecosystems, a general conceptual model is developed with reference to patterns, processes, and forces of change in agricultural land use at different spatial scales. The definition of agroecosystem health adopted for this research is defined as the system's ability to realize its functions desired by society and to maintain its structure needed both by its functions and by society over a long time period. General criteria for characterizing the structural, functional, organizational, and dynamic health of agroecosystems are identified, and their potential utility assessed. The identified general criteria are further developed as five agroecosystem health indicators relating to different aspects of changes in agricultural land use. They are changes in agricultural land resource availability, land use diversity, productivity, self-dependence, and land use stability. A conceptual framework is then developed to further an understanding of the stress-response relationships involved in these aspects of changes in agricultural land use. The framework also facilitates the identification of driving factors/attributes related to macro-level environments.;The proposed framework for assessing agroecosystem health is tested in two case studies. The first case study investigates the changes in agricultural land use to southern Ontario over a twenty year period from 1971 to 1991, and the second in Wellington County over the period 1986-91. Using four measurable indicators of land use change and secondary census data, the macro-scale study identifies that both structural and organizational health of the southern Ontario agroecosystem have deteriorated noticeably while the functional health has improved greatly. The macro-scale case study also concludes that the changes in agroecosystem health are significantly associated with the various forces related to biophysical conditions, changes in technology, changes in economic conditions, and modifications in institutional and social settings. According to two indicators of land resource availability and diversity, the county level study identifies that the structural health of the agroecosystem has also undergone a decline. The study reveals that the level of decline in the structural health is higher in northeastern Wellington than in the southwestern part of the county. Also, the changes are associated with different processes of land use conversion among agricultural land, forest, scrubland, and urban related uses.;The analytical approach in the first case study demonstrates the utility of censuses and other secondary information for assessing the dynamics of agroecosystem health at a macro scale. It shows how the specific health indicators can be measured, and how GIS and statistical methods can be used to analyze the relationships in the changes of agroecosystem health. The second case study illustrates the utility and limitation of the remote sensing approach for studying the short term change in agroecosystem health at a meso-scale. (Abstract shortened by UMI.)
机译：本文从农业土地利用的角度出发，开发并测试了评估农业生态系统健康变化的概念框架。为了理解农业生态系统中的动态关系，提出了一个通用的概念模型，该模型参考了农业生态系统中的变化模式，过程和变化力。不同空间尺度上的农业土地利用。本研究采用的农业生态系统健康定义是指该系统在很长一段时间内实现社会所需的功能并维持其功能和社会所需的结构的能力。确定了表征农业生态系统结构，功能，组织和动态健康的一般标准，并评估了其潜在效用。所确定的一般标准将进一步发展为与农业土地利用变化的不同方面有关的五种农业生态系统健康指标。它们是农业土地资源可用性，土地利用多样性，生产力，自立性和土地利用稳定性的变化。然后，开发了一个概念框架，以进一步理解与农业土地利用变化的这些方面有关的压力-反应关系。该框架还有助于识别与宏观环境有关的驱动因素/属性。在两个案例研究中测试了拟议的评估农业生态系统健康的框架。第一个案例研究调查了1971年至1991年的20年间安大略省南部农业用地的变化，第二个案例研究了1986-91年期间的惠灵顿县。宏观研究使用四个可衡量的土地利用变化指标和二次人口普查数据，确定了安大略省南部农业生态系统的结构和组织健康状况均已显着恶化，而功能健康状况则得到了很大改善。宏观案例研究还得出结论，农业生态系统健康的变化与与生物物理条件，技术的变化，经济条件的变化以及制度和社会环境的变化有关的各种力量显着相关。根据土地资源的可获得性和多样性的两个指标，县级研究确定农业生态系统的结构健康状况也在下降。研究表明，惠灵顿东北部的结构健康下降水平高于该县西南部。此外，这些变化还与农业用地，森林，灌丛和城市相关用途之间土地使用转换的不同过程相关。在第一个案例研究中的分析方法证明了普查和其他辅助信息在评估农业生态系统动态方面的效用。宏观健康。它显示了如何测量特定的健康指标，以及如何使用GIS和统计方法来分析农业生态系统健康变化中的关系。第二个案例研究说明了遥感方法在中尺度上研究农业生态系统健康的短期变化的实用性和局限性。 （摘要由UMI缩短。）

著录项

  • 作者

    Xu, Wei.;

  • 作者单位

    University of Guelph (Canada).;

  • 授予单位 University of Guelph (Canada).;
  • 学科 Biology Ecology.;Geography.;Agriculture General.;Environmental Sciences.;Urban and Regional Planning.
  • 学位 Ph.D.
  • 年度 1997
  • 页码 287 p.
  • 总页数 287
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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