BE/CNH: Biocomplexity of the Greater Serengeti: Humans in a Biologically Diverse Ecosystem

大塞伦盖蒂生态系统（以下简称“塞伦盖蒂”）是一个复杂的人类与自然耦合系统，由在异质景观上展开的多样化且强烈的营养相互作用网络组成。 牲畜和种类丰富的大型食草哺乳动物消耗了初级植物生产的很大一部分，其中数量最多的每年迁徙面积超过 12,000 平方公里。 这些食草动物维持着人类种群以及丰富的鸟类和哺乳动物食肉动物群。 此外，人类、野生动物和牲畜都容易感染多种传染病。 土地利用的大范围异质性叠加在这种动态景观上。 塞伦盖蒂国家公园是保护区和生态旅游目的地的典型例子，而邻近的恩戈罗恩戈罗保护区允许马赛人畜牧业、野生动物保护区（马斯瓦和伊科龙戈）允许战利品物种的控制捕捞，以及允许除农业以外的所有人类活动的野生动物控制区（格鲁梅蒂）。 塞伦盖蒂的人类和自然组成部分之间的联系如此普遍，以至于人类决策可能是决定整个生态系统命运的关键过程。 随着人类和动物种群聚集在塞伦盖蒂国家公园 (SNP) 和马拉保护区的西部边界，压力越来越大。 为了研究大塞伦盖蒂地区自然生态系统功能与人类决策的耦合，这个跨学科研究项目将使用四种建模方法：（1）将开发过程丰富、空间明确的生态系统模拟模型，以预测植物和动物群落的变化以及人类对不同尺度景观的利用。 (2) 基于代理的模型将在空间明确的环境中纳入个体决策规则。 (3)群落模块的分析模型将探索5至10个关键物种之间的相互作用。 (4) 宏观生态模型将系统模式和过程描述为主要资源投入（例如降雨和土壤养分）的函数。 这些模型将探索塞伦盖蒂在不同组织规模上的新兴动态。 将分析大量塞伦盖蒂实地数据，以参数化模型并评估其解释过去动态和当前生态系统趋势的能力。 此外，还将收集有关人类活动和选择的重要新数据，以了解自然成分和人类主导成分之间的系统动力学耦合。 不同建模方法和数据合成的结合将实现生态科学和社会科学的独特整合。 生态系统恢复力/抵抗力的概念将与人类社会的脆弱性直接相关。复杂系统理论提出，突现属性可以由在空间和时间上传播的相对简单的潜在机制产生。 塞伦盖蒂地区人类的脆弱性和生物多样性的可持续性可能是由一些独立于各个组成部分运作的关键限制因素驱动的。 这些限制源于心理学、生物学、化学和物理学的基本定律/原理，这些定律/原理限制了关键的生物过程和人类决策。 或者，复杂系统可能对初始条件的微小差异敏感，并表现出在替代状态之间切换的趋势。 这种敏感性表明，生物多样性和人类福祉可能高度取决于个体行为、参与物种的身份以及人类、植物、动物和疾病之间相互作用的精确空间安排等细节。 塞伦盖蒂提供了一个独特的机会来检验这一假设，因为它的组成部分非常引人注目，而且它的动态模式已经被测量了 40 年。 最后，新兴系统特性可能仅取决于几个关键组成部分，这意味着塞伦盖蒂可以通过几个关键植物/动物物种和人类之间的相互作用网络来理解。 除了提供基础的新知识外，该项目还将为研究地区和许多其他地区的管理者和决策者提供具有直接价值的见解和信息。 它还将为学生和博士后学者提供宝贵的研究和培训机会，并将促进美国和非洲科学家之间的国际合作。 该项目得到了 2003 财年环境生物复杂性特别竞赛的奖项的支持，该竞赛重点关注自然和人类系统耦合的动力学。

The Greater Serengeti Ecosystem (hereafter "the Serengeti") is a complex coupled human and natural system consisting of a network of diverse and intense trophic interactions played out over a heterogeneous landscape. Livestock and a species-rich assemblage of large mammalian herbivores, the most abundant of which migrate over a 12,000 square-km area each year, consume a high fraction of primary plant production. These herbivores sustain human populations and a rich assemblage of avian and mammalian carnivores. Moreover, humans, wild animals, and livestock are all vulnerable to a wide variety of infectious diseases. Broad-scale heterogeneity in land use is superimposed on this dynamic landscape. The Serengeti National Park is a classic example of a protected area and ecotourism destination, while the adjacent Ngorongoro Conservation Area permits Maasai pastoralism, game reserves, (Maswa and Ikorongo) permit-controlled off-take of trophy species, and game-controlled areas (Grumeti) that permit all human activity except agriculture. The linkages between human and natural components of the Serengeti are so pervasive that human decision making may be the critical process governing the fate of the entire ecosystem. Pressure is mounting as human and animal populations converge on the western border of Serengeti National Park (SNP) and Mara Reserve. To study the coupling of natural ecosystem functioning and human decision making in the greater Serengeti, this interdisciplinary research project will use four modeling approaches: (1) Process-rich, spatially explicit ecosystem simulation models will be developed to predict changes in plant and animal communities as well as human use of landscapes at different scales. (2) Agent-based models will incorporate individual decision-making rules in a spatially explicit environment. (3) Analytical models of community modules will explore interactions among five to ten key species. (4) Macro-ecological models will describe system patterns and processes as functions of major resource inputs, such as rainfall and soil nutrients. These models will explore emergent dynamics of the Serengeti at various organizational scales. A large amount of Serengeti field data will be analyzed to parameterize the models and to assess their ability to explain past dynamics and current ecosystem trends. In addition, crucial new data on human activities and choices will be collected to understand the coupling of system dynamics between natural and human-dominated components. This blend of different modeling approaches and data syntheses will permit a unique integration of ecological and social sciences. The concept of ecosystem resilience/resistance will be directly related to the vulnerability of human societies.The theory of complex systems proposes that emergent properties can arise from relatively simple underlying mechanisms propagated in space and time. The vulnerability of humans and sustainability of biodiversity in the Serengeti may be driven by a few critical constraints that operate independently of individual components. These constraints arise from fundamental laws/principles in psychology, biology, chemistry, and physics that constrain key biological processes and human decisions. Alternatively, complex systems may be sensitive to small differences in initial conditions and show a tendency to switch between alternative states. This sensitivity suggests that biodiversity and human welfare may be highly contingent on details such as individual behavior, the identity of the species participating, and the precise spatial arrangement of interactions among humans, plants, animals, and diseases. The Serengeti provides a unique opportunity to test this hypothesis, because its component parts are so conspicuous and its dynamical patterns have been measured for 40 years. Finally, emergent system properties may be contingent on just a few critical components, which would imply that the Serengeti can be understood from networks of interaction among a few key species of plants/animals and humans. In addition to providing fundamental new knowledge, the project will provide insights and information of immediate value of managers and decision makers in the study region and many other locales. It also will provide valuable research and training opportunities for students and post-doctoral scholars, and it will facilitate international collaborations between U.S. and African scientists. This project is supported by an award resulting from the FY 2003 special competition in Biocomplexity in the Environment focusing on the Dynamics of Coupled Natural and Human Systems.