Collaborative Research: Compensatory VS Amplifying Effects of Community Structure on Ecological Systems in Response to Environmental Fluctuations

智力价值：生态系统属性的动态是由生态系统内相互作用的物种的动态调节的，但人们对这是如何发生的知之甚少。理论工作表明，生态系统属性的动态将在很大程度上取决于对这些属性具有相似影响的物种的动态如何相关。一些研究表明，这些物种之间的补偿动力学涉及其波动的负相关，对稳定生态系统波动很重要。然而，有几个理由认为，这种补偿动力学只发生在有限的条件下，同步动力学（物种波动中的正相关）也可能发生。这种同步动态往往会放大生态系统属性的波动。补偿动力学和同步动力学发生的条件很少被理解，也没有很好的文献记录。一种假设认为，补偿动力学取决于三个因素：首先，对生态系统属性有相似影响的物种必须表现出足够大的权衡，以允许补偿的可能性。其次，环境必须随着这些权衡所涉及的因素而适当波动。第三，表现出这些权衡的物种只有在彼此不太相似的情况下才能共存。这一套想法和假设将通过实验操纵受到不同类型外部反复波动的池塘群落的多样性、组成和食物网结构来检验。这项工作将为了解群落结构的各个方面影响生态系统的方式提供重要的见解。这对基础科学和向社会通报人类改变生物群落和环境变化的潜在生态系统后果具有关键意义。更广泛的影响：本研究将通过以下方式对教育和社会做出贡献：1)融入俄勒冈州立大学（非博士学位授予机构）和德克萨斯大学的本科生教学。2)直接参与并指导从这些机构中选出的学生进行实地研究。3)直接支持研究生和博士后参与拟开展的研究或自己设计的密切相关的项目。4)所有这些参与者都将通过出版物和会议发言参与成果的传播。5)开发新的统计方法来分析生态数据，并将这些方法提供给其他人（通过网络）。6)通过环境统计中心（美国环境保护署资助的芝加哥大学环境问题统计研究中心）为研究目的提供数据。通过与NCEAS、弹性联盟、欧空局等适当组织建立联系，寻求传达可能引起社会环境关注的结果的方法。

Intellectual merit: The dynamics of ecosystem attributes are regulated by the dynamics of the interacting species within ecosystems, yet little is known about how this occurs. Theoretical work suggests that the dynamics of ecosystem attributes will depend strongly on how the dynamics of species with similar effects on these attributes are related. Some studies have suggested that compensatory dynamics among such species involving negative correlationsin their fluctuations are important in stabilizing ecosystem fluctuations. However there are several reasons to think that such compensatory dynamics only occur under limited conditions and that synchronous dynamics (positive correlations in species fluctuations) are also likely. Such synchronous dynamics would tend to amplify oscillations in ecosystem attributes. The conditions under which compensatory vs synchronous dynamics occur is poorly understood and not well documented. A hypothesis states that compensatory dynamics depend on three factors: First, species with similar effects on ecosystem attributes must show trade-offs that are sufficient in magnitude to allow the possibility of compensation. Second, the environment must fluctuate appropriately with respect to factors involved in these trade-offs. Third, species that show these trade-offs must coexist only if they are not too similar to each other. This set of ideas and hypotheses will be tested by experimentally manipulating the diversity,composition and food-web structure of pond communities subjected to different types of external recurrent fluctuations. This work will provide important insights into the ways that various aspects of community structure affect ecosystems. This is of key interest for both basic science and for informing society about the potential ecosystem consequences of human alteration of biological communities and environmental change.Broader impacts: This research will contribute to education and society by:1) Being integrated into the teaching of undergraduate students at OWU (a non-PhD granting institution) and UT. 2) Directly involving and mentoring selected students from these institutions into field research. 3) Directly supporting graduate students and post-docs involved the proposed research or in closely related projects of their own design. 4) All of these participants will be expected to be involved in the dissemination of results via publications and presentations at meetings. 5) Developing new statistical methods for analysis of ecological data and making these methods available to others (via the web). 6) Making data available for research purposes through the Environmental Statistics Center (an EPA-funded center for statistical research on environmental problems at the University of Chicago). Seeking ways to communicate results that might inform societal environmental concerns via networking with appropriate organizations such as NCEAS, Resilience Alliance, ESA etc.