Collaborative: Biodiversity, Trophic Structure, and Productivity -- An Experimental Test in Pond Ecosystems

9509004雷博德提出了各种各样的机制来解释能量流调节生态群落生物多样性的方式。然而，旨在区分这些相互竞争的假说的实验工作相对较少。这些研究人员将对与富营养化和水生生物多样性有关的最可信的假设进行直接的实验测试。这些实验将在一系列中微生态系统中进行，它们提供了三个重要的优点：(1)营养负荷和营养结构都可以独立控制，(2)其他潜在的混杂因素可以控制，(3)预期的生物反应可以很容易地测量和评估。此外，还将在池塘中建立实验围栏，在更自然的条件下测试这些假设。最后，还将对天然池塘生物多样性的控制进行广泛的分析。这项研究的结果将证实或否定四个相互竞争的假说，这些假说被认为解释了自然系统中生物多样性的模式。此外，这项研究还将评估“自下而上”与“自上而下”因素在调节浮游生物多样性方面的相对重要性。如果未来旨在保护生物多样性的环境政策要以有效的科学前提为基础，这种知识尤其重要。最后，这项工作将加深对富营养化对自然湿地群落生物多样性的潜在有害影响的理解。

9509004 Leibold A wide variety of mechanisms have been proposed to explain the ways by which energy flow regulates the biodiversity of ecological communities. However, there has been relatively little experimental work aimed at discriminating among these competing hypotheses. These investigators will conduct direct experimental tests of the most plausible hypotheses relating eutrophication to biodiversity in aquatic communities. These experiments will be conducted in a series of mesocosms which provide three important advantages: (1) both nutrient loading and trophic structure can be independently manipulated, (2) other potentially confounding factors can be controlled, and (3) the expected biological responses can be easily measured and evaluated. Additional, experimental enclosures will be established in ponds to test these hypotheses under more natural conditions. Finally, extensive analyses of controls on biodiversity in natural ponds will be conducted, as well. The results of this study will confirm or reject four competing hypotheses that are believed to explain patterns of biodiversity in natural systems. Moreover, the research will assess the relative importance of "bottom-up" versus "top-down" factors in the regulation of plankton diversity. This knowledge is particularly important if future environmental policies directed at the protection of biodiversity are to be based on valid scientific premises. Finally, this work will provide an increased understanding of the potentially detrimental effects of eutrophication on biodiversity in natural wetland communities.