Department of Geography and Environmental Systems, University of Maryland, Baltimore County, Baltimore, Maryland, United States of America.
PLoS One. 2013 Sep 5;8(9):e73241. doi: 10.1371/journal.pone.0073241. eCollection 2013.
Rural populations are undergoing rapid changes in both their livelihoods and land uses, with associated impacts on ecosystems, global biogeochemistry, and climate change. A primary challenge is, thus, to explain these shifts in terms of the actors and processes operating within a variety of land systems in order to understand how land users might respond locally to future changes in broader-scale environmental and economic conditions. Using 'induced intensification' theory as a benchmark, we develop a generalized agent-based model to investigate mechanistic explanations of relationships between agricultural intensity and population density, environmental suitability, and market influence. Land-use and livelihood decisions modeled from basic micro-economic theories generated spatial and temporal patterns of agricultural intensification consistent with predictions of induced intensification theory. Further, agent actions in response to conditions beyond those described by induced intensification theory were explored, revealing that interactions among environmental constraints, population pressure, and market influence may produce transitions to multiple livelihood regimes of varying market integration. The result is new hypotheses that could modify and enrich understanding of the classic relationship between agricultural intensity and population density. The strength of this agent-based model and the experimental results is the generalized form of the decision-making processes underlying land-use and livelihood transitions, creating the prospect of a virtual laboratory for systematically generating hypotheses of how agent decisions and interactions relate to observed land-use and livelihood patterns across diverse land systems.
农村人口的生计和土地利用正在迅速变化，这对生态系统、全球生物地球化学和气候变化产生了相关影响。因此，主要的挑战是根据各种土地系统中运作的行为者和过程来解释这些变化，以了解土地使用者如何在更广泛的环境和经济条件下对未来的变化做出局部反应。我们使用“诱导强化”理论作为基准，开发了一个广义的基于主体的模型，以研究农业强度与人口密度、环境适宜性和市场影响之间关系的机制解释。从基本微观经济理论中建模的土地利用和生计决策产生了与诱导强化理论预测一致的农业强化的时空模式。此外，还探讨了对诱导强化理论所描述条件之外的主体行为的反应，揭示了环境约束、人口压力和市场影响之间的相互作用可能导致不同市场一体化程度的多种生计制度的转变。结果是新的假设，可以修改和丰富对农业强度和人口密度之间经典关系的理解。该基于主体的模型和实验结果的优势在于土地利用和生计转型背后的决策过程的广义形式，为如何通过主体决策和相互作用与观察到的土地利用和生计模式相关的假设的系统生成创造了前景，跨越不同的土地系统。
