BE/CNH: Virtual Watershed: Agricultural Landscape Evolution in an Adaptive Management Framework

在美国和其他有人居住的地区，农业用地约占土地的50%。有关农业用地使用的决定具有重大的经济和环境后果。虽然这些决定主要集中在粮食和纤维的生产上，但农业景观和流域也有可能通过对湿地恢复、河岸过滤带等自然资本的投资，以及改变增加土壤有机碳的耕作方法，促进生态系统服务（如养分循环、大气气体调节、土壤形成和野生动物栖息地）的流动。不幸的是，在有限的社会经济环境下，资源管理者愿意在当前进行大量私人投资，以便通过加强未来的生态系统服务流动来获得更大的公共环境效益。这个跨学科的研究项目将通过构建一个名为“虚拟流域”的空间决策支持系统来研究解决这一社会环境困境的方法。虚拟流域将结合环境模拟模型、地理信息系统、进化算法和基于主体的建模，捕捉经济和生态条件、公共政策、土地和水资源管理者的行为以及产生农村景观格局的其他变量之间的动态非线性相互作用。这些模式反过来又决定了流域尺度上的生态和经济表现。特别感兴趣的问题是景观随时间变化的复杂性，以及适应性管理过程在不断发展的环境和社会系统中引导景观变化以满足用户定义的社会目标的能力。对两个流域（一个在伊利诺斯州，另一个在魁北克）的案例研究将检验景观变化是否表现出“panarchy”概念中捕获的自组织复杂性，panarchy这个概念与人类-环境系统具有特征循环动力学的概念有关，这些循环动力学在一个层次上与更快和更慢的循环联系在一起。一个主要假设是，通过改变激励结构，农业景观的环境绩效可以显著改善，同时不减少土地管理者的收入。这些激励结构包括农业补贴、土地退休计划和实践成本分担等形式。此外，改善可以通过土地管理者对其他刺激因素的反应来实现，例如邻近的土地使用和邻居采用新的做法。该项目将进一步验证一个假设，即适应性管理过程首先模拟接近理论上最优的景观表现，然后用于调整土地管理者的决策环境，引导他们朝着最优方向发展，随着时间的推移，这一过程可以改善生态经济表现。尽管干扰事件和不断变化的社会偏好有可能将这种适应性管理过程变成没有改进的变化跑步机，而不是通往生态经济改善的道路，但这种情况仍然发生。在检验这些假设时，该项目将更好地了解经济条件和激励措施、环境政策、资源管理者行为和现有景观模式对景观变化动态的独立和相互依存作用，以及农业流域经济和生态目标之间的权衡和互补。视觉上得到改进的虚拟流域模型在教育和决策环境中将是有价值的。该项目得到了2004年度环境生物复杂性特别竞赛的支持，该竞赛侧重于自然和人类系统耦合动力学。

Agricultural land constitutes about 50 percent of the land in the U.S. and other inhabited regions. Decisions regarding the use of agricultural land have significant economic and environmental consequences. While these decisions are focused mainly upon the production of food and fiber, agricultural landscapes and watersheds also have the potential to produce enhanced flows of ecosystem services (such as nutrient cycling, regulation of atmospheric gases, soil formation, and wildlife habitat) through investments in natural capital like wetland restoration, riparian filter strips, and changes in farming methods that increase soil organic carbon. Unfortunately, there is a narrow range of socioeconomic circumstances under which resource managers are willing to make substantial private investments in the present to achieve more substantial public environmental benefits through enhanced flows of ecosystem services in the future. This interdisciplinary research project will investigate solutions to this socio-environmental dilemma by constructing a spatial decision-support system called Virtual Watershed. Virtual Watershed will combine environmental simulation models, geographic information systems, evolutionary algorithms, and agent-based modeling to capture the dynamic nonlinear interactions among economic and ecological conditions, public policies, land and water managers' behavior, and other variables that generate rural landscape patterns. These patterns in turn determine ecological and economic performance at a watershed scale. Issues of particular interest are the complex nature of landscape change over time and the capability of adaptive management processes to guide landscape change to meet user-defined social goals in an evolving environmental and social system. Case studies in two watersheds (one in Illinois and the other in Quebec) will examine whether landscape change displays self-organized complexity as captured in the concept of "panarchy," a concept associated with the idea that human-environment systems have characteristic cyclic dynamics that are linked in a hierarchy to faster and slower cyclesThis project has clear and direct applications in environmental and agricultural policy. One primary hypothesis is that the environmental performance of agricultural landscapes can be markedly improved while not reducing income to land managers through changes in incentive structures. Such incentive structures include among others, forms of agricultural subsidization, land retirement programs, and cost sharing for practices adoption. Additionally, improvement can occur though the responses of land managers to other stimuli, such as neighboring land uses and neighbors' adoption of new practices. The project will further test the hypothesis that an adaptive management process that first simulates near theoretically optimal landscape performance and then is used to adjust the decision environments of land managers to guide them toward that optimum can result in improved ecological-economic performance over time. This occurs despite disturbance events and changing social preferences that have the potential to turn this adaptive management process into a treadmill of change without improvement rather than a path toward ecological-economic improvement. In testing these hypotheses, the project will achieve a better understanding of the independent and interdependent roles of economic conditions and incentives, environmental policies, resource manager behavior, and pre-existing landscape patterns on the dynamics of landscape change as well as trade-offs and complementarities among economic and ecological goals for agricultural watersheds. The visually improved Virtual Watershed model will be valuable in educational and policy-making settings. This project is supported by an award resulting from the FY 2004 special competition in Biocomplexity in the Environment focusing on the Dynamics of Coupled Natural and Human Systems.