Collaborative Research: Evaluating Species Redundancy in Stream Detrital Processing

9707500 Covich Detritivores在森林集水区的源头流获得他们的能量和营养物质主要来自河岸落叶输入。在切碎和刮除落叶的过程中，它们将微生物调节的叶子转化为下游悬浮饲养者使用的有机颗粒。本提案将探讨以下问题。在这个过程中，某些食虫动物是否扮演着重要的角色？在决定叶加工速度和向下游消费者输出悬浮颗粒物的速度时，其他物种是否多余？一个或多个食草动物物种的损失可能会改变叶加工河流生态系统，但流生态学家缺乏经验，流为基础的方法来确定是否有独特的作用，在落叶处理或如果他们的相互作用是重要的其他食草动物。一个或多个物种的损失将不会影响整体处理率，如果食草物种是多余的，并没有互动或独特的物种特定的作用，在叶凋落物处理。或者，如果某些底栖食草物种发挥关键作用，则随着这些物种的丧失或取代，即时落叶处理率将下降。这项研究将确定不同的食草动物物种是否相互独立地发挥作用，作为彼此的替代品或替代品，以消极的抑制方式，或以积极的促进方式。 这项研究在孤立的流的结果将提供跨站点之间的比较不同种类的食草动物正在进行的研究，叶凋落物处理在卢基略LTER网站的数据。此外，这项研究将提供深入了解引进物种对生态系统功能的影响相比，明显相似，本地物种的功能作用。

9707500 Covich Detritivores in headwater streams of forested catchments obtain their energy and nutrients primarily from riparian leaf litter input. In the process of shredding and scraping leaf litter they transform microbially conditioned leaves into organic particulates used by downstream suspension feeders. This proposal will investigate the following questions. Do some detritivore species play essential roles in this processing? Are other species redundant in determining the rate of leaf processing and export of suspended particulates to downstream consumers? The loss of one or more detritivore species may alter leaf processing in fluvial ecosystems, yet stream ecologists lack an empirical, stream-based approach for determining if species have unique roles in leaf litter processing or if their interactions are important to other detritivores. The loss of one or more species will not influence overall rates of processing if detritivore species are redundant and have no interactive or unique species-specific role in leaf-litter processing. Alternatively, rates of instream leaf-litter processing will decrease with the loss or replacement of certain benthic detritivore species if these species perform key functions. This research will determine if different detritivore species function either independently of each other, as substitutes or replacements for one another, in a negative, inhibitory manner, or in a positive, facilitative manner. Results of this research in isolated streams will provide data for cross-site comparisons among different species of detritivores from on-going studies of leaf-litter processing at the Luquillo LTER site. In addition, this research will provide insight into the effects of introduced species on ecosystem function in comparison to the functional role on apparently similar, native species.