Dissertation Research: Periwinkle Grazing On and Control of Spartina Alterniflora.

许多水生群落已被证明是由上而下的控制，而大多数系统占主导地位的维管植物被认为是由下而上的力量控制。近50年来，盐沼生态学的主流范式一直是自下而上的力量，如养分的有效性，是沼泽草产量的主要决定因素。在这个建议中，我们表明，在西部南极洲盐沼的优势植物的现存量减少批发和基板完全裸露时，捕食者不抑制密度的最常见的放牧无脊椎动物在东南沼泽，长春滨藜。然而，在这些结果可以被普遍接受之前，我们的观察，滨藜广泛地吃草对生活米草和目前的范式，认为滨藜是最重要的食草动物在沼泽系统之间的明显矛盾必须得到解决。为此，我们提出了一个详细的研究计划，以获得一个机制的理解，滨藜-活米草相互作用。这项研究的结果可能会迫使我们重新评估我们目前对沼泽系统的理解，并为正在进行的关于维管植物群落是否容易受到消费者影响的争论提供关键信息。

Project SummaryMany aquatic communities have been shown to be under top-down control, while most systemsdominated by vascular plants are assumed to be controlled by bottom-up forces. For nearly50 years, the prevailing paradigm in salt marsh ecology has been that bottom-up forces,such as nutrient availability, are the primary determinants of marshgrass production. Inthis proposal, we show that the standing crop of the dominant plant in western Atlanticsalt marshes is reduced wholesale and the substrate completely denuded when predators donot suppress densities of the most common grazing invertebrate in southeast marshes, theperiwinkle Littoraria irrorata. Before these results can be generally accepted, however,the apparent contradiction between our observations that Littoraria graze extensively onlive Spartina and the current paradigm which holds that Littoraria is the most importantdetritivore in the marsh system must be resolved. To do this, we present a detailedresearch plan to obtain a mechanistic understanding of the Littoraria - live Spartinainteraction. Results from this study will likely force us to reevaluate our currentunderstanding of marsh systems and add critical information to the ongoing debate as towhether or not vascular plant communities are susceptible to run-away consumer effects.