Collaborative Research: Evaluating Species Redundancy in Stream Detrital Processing

9707500在森林集水区的源头溪流中的科维奇有害动物主要从河岸落叶输入中获得能量和营养。在粉碎和刮除落叶的过程中，它们将经过微生物调节的叶子转化为有机颗粒，供下游的悬浮喂食器使用。该提案将调查以下问题。一些有害物种是否在这一过程中发挥了重要作用？其他物种在确定叶加工和向下游消费者出口悬浮颗粒物的速度时是否多余？一个或多个有害物种的丧失可能会改变河流生态系统中的树叶加工，但河流生态学家缺乏一种基于河流的经验方法来确定物种在落叶处理中是否具有独特的作用，或者它们的相互作用是否对其他有害动物很重要。一个或多个物种的丧失不会影响总的处理速度，如果更多的物种是多余的，并且在落叶处理中没有相互作用或独特的物种特有作用。或者，如果某些底栖有害生物物种发挥关键作用，则随着这些物种的丧失或替换，河流凋落物的处理率将会降低。这项研究将确定不同的有害物种是否以消极的、抑制的方式或积极的、促进的方式发挥作用，或者相互独立，作为彼此的替代品或替代物。这项在孤立溪流中的研究结果将为卢基洛LTER地点正在进行的树叶凋落物处理研究中不同种类的有害食肉动物之间的跨地点比较提供数据。此外，这项研究将深入了解引进物种对生态系统功能的影响，并与表面上相似的本地物种的功能作用进行比较。

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.