Agricultural landscape change and stability in northeast Thailand: historical patch-level analysis
Agricultural landscape change and stability in northeast Thailand: historical patch-level analysis
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DOI：
10.1016/j.agee.2003.09.024
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发表时间：
2004-02-01
影响因子：
6.6
通讯作者：
Crews-Meyer, KA
中科院分区：
文献类型：
--
作者：
Crews-Meyer, KA
农业景观变化的时间性质，其中年内和年间的过程和变化往往是起作用的，使得传统的景观变化评估方法不完全有效。此外，季节性和长期的耕作模式有时可能看起来像是永久性的景观变化，而实际上它们只是局部空间安排的变化。为了解决这些复杂性，这项工作测试了一种纵向的方法，该方法基于对景观变化的结构以及土地利用/土地覆盖(LULC)变化的评估。以泰国东北部农村为背景，通过使用由图像时间序列构建的LULC变化轨迹和由模式度量构建的时间模式来检查斑块的动态。给定的观测单位是像素，它的“生命史”由卫星时间序列图像的值构成，然后在斑块级别进行重构，以便更好地进行生态解释。支持这一方法的假设是，弹道的性质与该地块和周围地块附近土地的功能有关。因此，土地利用/土地利用/土地利用的空间布局的不同轨迹可能表明土地利用/土地利用/土地利用的稳定性或动态在时间和空间上的差异，这进一步暗示土地的可持续性或复原力，或者相反，土地转换或动态。这项研究的研究领域是泰国东北部被边缘化的农业环境，该地区经历了为种植商业大田作物而砍伐旱地森林、为谋生而强化低地水稻以及当地和区域销售和全球出口，以及作为背景矩阵的改变稀树大草原景观的土地利用/土地利用/土地利用变化方案。本文的分析在斑块水平上表征了LULC的相对稳定性和时间动力学。在斑块水平上计算的格局度量被评估为景观单元的空间组织，这些景观单元代表：(1)作为外围扩展发生的土地利用/土地利用变化动态的过渡区；(2)通过砍伐森林从森林向农业转变的土地利用/土地利用变化；或(3)通过次生植物演替从农业向森林转变，以稀树草原为过渡基质。总之，本文提出并测试了一种基于模式度量的LULC时间持久性评估方法。该方法提供了一种技术，用于在尺度明确的背景下分析场地作为其稳定性/动态的函数的景观生态，并有助于相关尺度、模式和过程的工作的不断增长。(C)2003爱思唯尔B.V.保留所有权利。
The temporal nature of agricultural landscape change, where both intra- and inter-annual processes and changes are often at work, renders traditional methods of landscape change assessment not completely effective. Additionally, seasonal and longer-term shifting patterns of cultivation can sometimes appear as permanent landscape change when in fact they actually are simply a local change in spatial arrangement. To address these complexities, this work tests an approach that is longitudinal in character and based upon assessing the structure of landscape change as well as the landuse/landcover (LULC) change. Set in rural northeast Thailand, patch dynamics are examined through use of LULC change trajectories built from an image time series and temporal patterns built from pattern metrics. The given unit of observation is the pixel, and its "life history" is constituted by the values derived from the images of a satellite time series, which are then reconstituted at the patch level for better ecological interpretation. The hypothesis that underpins this approach is that the nature of the trajectory is associated with the function of the land in that patch and in the neighborhood of surrounding patches. Hence, different trajectories of LULC spatial arrangement may suggest, for example, differences in the stability or dynamics of LULC over time and space, which are further suggestive of land sustainability or resilience, or conversely land conversion or dynamism. The study area for this research is a marginalized, agrarian environment in northeast Thailand, a region that has undergone deforestation of upland forests for the cultivation of commercial field crops, intensification of lowland rice for subsistence as well as local and regional sales and global export, and LULC scenarios altering the savanna landscape that serves as the background matrix. The analysis here characterizes the relative stability and temporal dynamics of LULC at the patch level. Pattern metrics calculated at the patch level are assessed as the spatial organization of landscape units that represent: (1) transitional areas of LULC dynamics occurring as peripheral expansion, (2) LULC change from forest to agriculture through deforestation, or (3) agriculture to forest through secondary plant succession, with savanna serving as a transitional matrix. In short, this paper proposes and tests a method for assessing the temporal persistence of LULC through pattern metrics. The method contributes a technique for analyzing the landscape ecology of sites as a function of their stability/dynamics within a scale-explicit context, and contributes to the growing body of work on relating scale, pattern, and process. (C) 2003 Elsevier B.V. All rights reserved.