BE/CNH: Biocomplexity of Integrated Perennial-Annual Agroecosystems

农业生态系统是地球上最复杂、最错综复杂的人类和自然系统组合之一。在全球范围内，集约化粮食生产的后果与生物物理系统和人类系统的健康和稳定密切相关。在美国中西部，一年生作物几乎完全取代了多年生植被，严重影响了维持人类和生物物理系统功能和稳定性的环境服务。通过在农业景观中重新引入多年生植被来扭转这些趋势的可能性，可以通过两个平行的过程来强调：(1)农业政策越来越重视促进包括多年生植物的保护措施；(2)越来越多的实地和模型研究证据表明，增加多年生植被覆盖可以显著提高生态和社会经济效益。然而，关于人类和生物物理系统内部复杂的原因和反馈，将最终决定多年生系统中这些变化的程度和方向，目前严重缺乏基本的科学知识。该项目将把流域尺度的田间试验与建模模拟结合起来，以评估与中西部地区以一年生作物为主的农业生态系统中多年生植被整合相关的生态和社会经济动态以及权衡。该项目将在爱荷华州中部核桃溪流域的尼尔史密斯国家野生动物保护区进行，那里大约三分之一的流域已经转变为原生草原植被，产生了农业用地和原生草原植被的马赛克景观，为本研究提供了理想的环境。本研究的核心假设是，在以农业为主的景观中，多年生植物覆盖的战略位置、数量和类型将对生物物理（即水质和流量、生物多样性）和社会经济（即生活质量、经济和社会稳定）系统的功能产生不成比例的影响。该项目的主要目标是开发一个基于基线经济和生物物理数据的环境效率指数，该指数将能够评估具有不同一年生植物配置的不同景观设计在多大程度上优化了生态系统功能和社会经济效益。该项目将包括参数化、验证和明确联系生物物理和经济模型，这些模型将用于评估各种多年生流域情景的环境效益和经济成本。该项目将通过开发评估农业景观生物复杂性的新方法，并通过提供有助于实现积极的环境和社会经济变化的政策的知识，对科学和社会产生重大影响。该项目将产生一个决策工具的原型，可由一系列政府机构和民间社会组织用于指导管理和政策决策，从而为评估各种集约管理景观的权衡提供科学依据。它将建立对将多年生植被纳入以年为主导的农业系统的全部社会成本和效益的科学理解，以及目前影响更有效地制定政策所需的保护措施的采用和支付的复杂动态。该项目将通过为本科生和研究生提供教育机会，以及通过保护区的学习中心开展的公共教育和推广活动，提高对集约化管理系统的生物复杂性的认识，并在整个社会中提供可供选择的分水岭设计方案，该中心将针对广泛的利益相关者（如政策制定者、学童、农民等）。通过该项目开发的结果和方法将广泛应用于评估替代性集约管理景观的权衡，并指导美国和国外其他地区的管理和政策决策。该项目得到了2005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。

Agroecosystems are among the most complex and intricately coupled sets of human and natural systems on Earth. On a global scale, the consequence of intensive food production is closely linked to the health and stability of both biophysical and human systems. In the Midwestern U.S., the almost-complete replacement of perennial-dominated vegetation by annual crops has significantly impacted environmental services that maintain function and stability of both the human and biophysical systems. The possibility that these trends can be reversed through the re-introduction of perennial vegetation into agricultural landscapes is underscored by two parallel processes: (1) the increasing emphasis of agricultural policies on promoting conservation practices that incorporate perennial plants, and (2) increasing evidence from field and modeling studies suggesting that increasing perennial cover may significantly enhance both ecological and socioeconomic benefits. Fundamental scientific knowledge is sorely lacking, however, with respect to the complex causes and feedbacks within the human and biophysical systems that will ultimately determine the degree and direction of these changes in perennial-annual systems. This project will integrate a watershed-scale field experiment with modeling simulations to assess coupled ecological and socioeconomic dynamics and trade-offs associated with integrating perennial vegetation in agroecosystems dominated by annual crops in the Midwest. The project will be conducted at the Neal Smith National Wildlife Refuge in the Walnut Creek watershed in central Iowa, where approximately one-third of the watershed has been converted to native prairie vegetation, producing a mosaic landscape of agricultural lands and native prairie vegetation that provides an ideal context for this research. The core hypothesis for this research is that strategic locations, amounts, and types of perennial plant cover within agriculturally-dominated landscapes will have a disproportionate effect on the functioning of the biophysical (i.e., water quality and flow, biodiversity) and socioeconomic (i.e., quality of life, economic and social stability) systems. The main objective of this project is to develop an environmental-efficiency index derived from baseline economic and biophysical data that will enable assessment of the extent to which different landscape designs having contrasting annual-perennial plant configurations optimize ecosystem functioning and socioeconomic benefits. This project will include parameterizing, validating, and explicitly linking biophysical and economic models that will be used to assess the environmental benefits and economic costs of various perennial-annual watershed scenarios.This project will have significant impacts on science and society by developing novel approaches to assessing biocomplexity in agricultural landscapes and by providing knowledge that will contribute to policies aimed at effecting positive environmental and socioeconomic change. The project will result in a prototypic decision-making tool that can be applied by a range of governmental agencies and civil society organizations to guide management and policy decisions, thereby offering a scientific basis for assessing trade-offs of alternative intensively managed landscapes. It will establish a scientific understanding of the full societal costs and benefits of integrating perennial vegetation into annually dominated agricultural systems and of the complex dynamics currently influencing adoption and payments of conservation practices that is needed for more effective policy formulation. The project will enhance knowledge of biocomplexity of intensively managed systems and alternative watershed design options within society as a whole by providing educational opportunities for undergraduate and graduate students as well as through public education and outreach activities conducted through the refuge's learning center that will target a wide range of stakeholders (e.g., policy makers, school children, farmers, etc.). The results and approach developed through this project will have broad applications to assessing trade-offs of alternative intensively managed landscapes and guiding management and policy decisions in other regions in the U.S. and abroad. This project is supported by an award resulting from the FY 2005 special competition in Biocomplexity in the Environment focusing on the Dynamics of Coupled Natural and Human Systems.