BE/CNH: Interactions Among Human, Biological, and Physical Processes Within Large Lake Ecosystems

以湖泊为基础的人类活动的繁荣一直伴随着大型湖泊生态系统服务质量的提高，包括丰富的斗鱼、清澈的水和用于饮用和游泳的未受污染的水。例如，伊利湖的水质和清晰度在1970年代和1980年代通过减少来自点源的外部磷负荷而大幅改善，随后一直延续到现在的湖边娱乐和住宅开发时期。最近，湖泊中磷浓度的增加和有害藻类水华的频繁出现，与其他生物物理条件相结合，产生了“令人惊讶的事件”，例如夏季“死亡区”的扩大和成年猎鱼的死亡。虽然人类和生物物理系统之间的联系显然是造成这些变化的关键因素，但它们的基本结构动态以及这种联系在多大程度上导致了生物和人类过程的根本性变化，或许是不可逆转的变化，目前尚不得而知。这一跨学科研究项目将研究湖泊功能和与湖泊相关的人类活动之间的耦合关系，并探索这些耦合如何在生态结果(如水质和鱼类种群)以及人类行为(包括土地利用和基于湖泊的娱乐活动)方面产生非线性变化。特别令人感兴趣的是耦合连接导致分叉或其他在没有耦合时可能不会发生的“意外”结果的条件，以及可能嵌入耦合中的细尺度变化、时滞反馈和随机过程的影响。本研究的目的是：(1)建立一个简单的、具有人-生物物理耦合作用的大型湖泊生态系统的大尺度模型，可用于考察系统动力学和人-生物物理耦合的作用；(2)通过提高模型的时空分辨率和利用伊利湖数据对模型进行参数化，建立一个更详细、更精细的模型，并使用该模型检验有关人类活动对湖泊富营养化的影响以及这些生态变化对伊利湖地区土地和经济发展的影响的假设；(3)利用这套模型研究历史政策和新的管理策略对人类和生物物理过程的影响。将使用分析、统计和计算机模拟方法的组合，包括基于代理的建模，来建立这些模型。动力系统技术，包括数值模拟和分叉分析，将被用来分析模型。关于湖泊动态、水质、鱼类种群、土地利用和娱乐活动的许多历史数据已经可用。将利用地理信息系统、遥感和对居民和湖泊娱乐用户的家庭调查产生更多数据。该项目将提供科学和社会效益。通过测试关于人类和生物物理大型湖泊过程之间耦合联系的假设，并研究这些相互作用如何影响生物和人类系统的自组织和弹性，该项目将为科学理解大型湖泊生物复杂性做出原创性贡献。这项研究将为研究复杂、耦合系统的稳定性和多尺度性质提供方法论上的贡献。通过更好地了解湖泊功能和人类行为反应之间的反馈是如何发生的，结果将产生社会效益，为寻求保护湖泊资源的政策制定者提供信息，同时也为人们提供高质量的便利设施。该项目将通过开发新的生物复杂性课程，通过培训新一代跨学科的生物复杂性研究人员，以及通过将研究想法和成果纳入K-12教育材料和方案，以政策制定者和更广泛的公众为目标，将生物复杂性研究与教育相结合。该项目得到了2004财年环境中生物复杂性特别竞赛的一个奖项的支持，该竞赛的重点是自然和人类耦合系统的动态变化。

Booms in lake-based human activities have consistently followed increases in the quality of large lake ecosystem services, including abundant gamefish, clear water, and uncontaminated water for drinking and swimming. For example, substantial improvements in water quality and clarity in Lake Erie achieved in the 1970s and 1980s through the reduction in external phosphorus loadings from point sources have been followed by a period of lakeside recreational and residential development that extends to the present. More recently, increases in phosphorus concentrations and the frequency of harmful algal blooms in the lake have combined with other biophysical conditions to generate "surprise events," such as the, expansion of the summertime "Dead Zone" and adult gamefish kills. While linkages between the human and biophysical systems clearly are key factors producing these changes, their underlying structural dynamics and the extent to which the linkages have led to fundamental and perhaps irreversible changes in biological and human processes is unknown. This interdisciplinary research project will examine the coupled linkages between lake functioning and lake-related human activities and explore how these couplings generate nonlinear changes in ecological outcomes, such as water quality and fish stocks, and human behavior, including land use and lake-based recreational activities. Of particular interest are the conditions under which coupled linkages lead to bifurcations or other "surprise" outcomes that may not occur in their absence and the influence of fine-scale variations, time-delayed feedbacks, and stochastic processes that may be embedded in the couplings. The objectives of this research are (1) to construct a simple, coarse-scale model of a generic large lake ecosystem with coupled human-biophysical interactions that can be used to examine system dynamics and the role of human-biophysical couplings; (2) to develop a more detailed, fine-scale model by increasing the model's spatial and temporal resolution and, parameterizing the model using Lake Erie data and use this model to test hypotheses regarding the impact of human activities on lake eutrophication and the impact of these ecological changes on land and economic development in the Lake Erie region; and (3) to use this set of models to study the impacts of historical policies and new management strategies of large lakes on both human and biophysical processes. A combination of analytical, statistical, and computer simulation methods, including agent-based modeling, will be used to build these models. Dynamical systems techniques, including numerical simulations and bifurcation analysis, will be used to analyze the models. Much of the historical data on lake dynamics, water quality, fish stocks, land use, and recreational activities are already available. Additional data will be generated using geographical information systems, remote sensing, and household surveys of residents and lake recreational users.The project will provide both scientific and societal benefits. By testing hypotheses regarding the coupled linkages between human and biophysical large lake processes and examining the way in which these interactions influence the self-organization and resiliency of biological and human systems, the project will make an original contribution to the scientific understanding of large lake biocomplexity. The research will make methodological contributions by advancing methods used to study the stability and multiscale properties of complex, coupled systems. By providing a better understanding of how feedbacks occur between lake functioning and human behavioral responses, the results will generate social benefits by providing information to policy makers who seek to protect lake resources while also providing high-quality amenities to people. The project will integrate biocomplexity research and education through the development of a new biocomplexity course; through training a new generation of interdisciplinary biocomplexity researchers; and through incorporation of research ideas and results into K-12 educational materials and programs aimed at policy makers and the broader public. 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.