RUI: Bottom-Up and Top-Down Influences on Processing Chain Interactions in Detritus-Based Communities

项目摘要：- 我知道自下而上和自上而下的影响，处理链的相互作用，在碎屑为基础的社区碎屑是主要的食物来源，为许多社区的生物，和食腐动物提供了一个生态系统服务，分解和消耗死的有机物。 落叶是其中几个以碎屑为基础的社区的主要能源投入，并形成了一个加工链的基础，其中树叶随着时间的推移而腐烂，消费者专门针对不同州的资源。 一些食草动物，被称为加工者，可以通过分解有机物质并将其从整个叶子变成更小的颗粒来促进其他食草动物的进食。 这种加工链的相互作用可以通过增加可供消费的资源类型来增加物种的多样性。 本研究的目的之一是了解资源加工如何调节群落结构。 自下而上和自上而下的力量也可能影响资源和加工链。 自下而上的影响，如落叶量，可能会决定是否加工链的相互作用是促进或竞争，以及如何强烈地影响其他消费者。 自上而下的力量，如顶级捕食者，可能会影响个别消费者，或间接影响加工速度的不利影响处理器。 本研究将确定自下而上和自上而下的影响的相对强度在树洞，一个模型碎屑为基础的食物网。充满水的树洞是小分解者社区，易于操作，并包含加工链的相互作用。 现场围隔和自然栖息地实验将被用来确定对食蟹动物群落和加工链的影响时，资源，处理器密度，和存在的捕食者系统地变化。 要测量的变量包括凋落物颗粒大小分布的变化、昆虫种类的密度和多样性以及微生物的多样性。 待检验的假设为：1）加工链相互作用和加工者增加了树洞中资源的多样性和丰富度，这影响了其他食虫昆虫和微生物的多样性和丰富度，2）加工者在资源有限时比在资源丰富时对食虫昆虫的多样性和丰富度有更大的积极影响，（3）顶级多面手捕食者会减少食草动物之间的竞争，降低加工者的影响，影响物种丰富度。 了解自下而上和自上而下的因素对碎屑处理和处理链的相对优势，将有助于更全面地了解这些因素如何影响群落结构和功能。

Project Abstract: RUI: Bottom-Up and Top-Down Influences on Processing Chain Interactions in Detritus-Based CommunitiesDetritus is the major food source for many communities of organisms, and detritivores provide an ecosystem service by breaking down and consuming dead organic matter. Leaf litter is the primary energy input to several of these detritus-based communities and forms the basis of a processing chain, where leaves decay over time and consumers specialize on resources in different states. Some detritivores, called processors, may facilitate other detritivores by breaking down organic matter and changing it from whole leaves to smaller particles upon which other detritivores feed. This processing chain interaction may increase the diversity of species by increasing the types of resources available for consumption. One objective of this research is to understand how processing of resources regulates community structure. Bottom-up and top-down forces may also influence resources and processing chains. Bottom-up influences, such as the amount of leaf litter, may determine whether processing chain interactions are facilitative or competitive, and how strongly they affect other consumers. Top-down forces, such as top predators, may affect individual consumers, or indirectly affect the rate of processing by adversely affecting processors. This research will determine the relative strengths of bottom-up and top-down influences on processing chain interactions in treeholes, a model detritus-based food web.Water-filled treeholes are small decomposer communities that are easily manipulated and contain processing chain interactions. Field mesocosm and natural habitat experiments will be used to determine the effects on detritivore communities and processing chains when resources, processor density, and presence of predators are systematically varied. Variables to be measured include changes in particle size distribution of leaf litter, the density and diversity of species of insects, and the diversity of microbes. The hypotheses to be tested are: 1) processing chain interactions and processors increase the diversity and abundance of resources in treeholes, which influences diversity and abundance of other detritivorous insects and microbes, 2) processors have a greater positive impact on diversity and abundance of detritivores when resources are limiting than when resources are abundant, and 3) a top generalist predator will decrease competition amongst detritivores, decreasing the impact of the processors, and affecting species richness. Understanding the relative strengths of bottom-up and top-down factors on detrital processing and processing chains will lead to a more complete understanding of how those factors affect community structure and function.