Collaborative Research & RUI: Spatial Patch Structure: Can Ephemeral and Heterogeneous Resource Patches Influence Biotic Assemblages in Streams

合作研究

• 批准号: 9981376
• 负责人: Margaret Palmer
• 金额: $ 14.75万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-02-15 至 2005-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9981376&HistoricalAwards=false
• 关键词: Collaborative; Research; & RUI; Spatial

In many ecosystems, the dominant habitat patches frequently change in terms of their overall quality or their resource levels. Periodically, habitat patches may be physically disrupted or destroyed. In such highly dynamic systems it often is assumed that mobile fauna will be unresponsive to the arrangement of habitat patches or to other landscape attributes. The underlying logic is that faunal responses to landscape attributes will be masked by the spatial and temporal variability of such systems. In this proposal, we argue that mobile fauna in highly dynamic systems are, in fact, responsive to landscape attributes - especially patch arrangement. Population persistence and species interactions following the disruption of patches or changes in resources may be influenced greatly by the quality and arrangement of patches. In prior NSF-funded research, we found that stream-dwelling chironomids and copepods respond to the quality and distribution of habitat (leaf) patches in laboratory and field experiments, but we did not consider how patch stability, patch resource (leaf species) composition, or predator-prey interactions influence faunal dynamics. Here, we hypothesize that invertebrate abundance in streambeds is better explained at the scale of multiple patches (the "landscape") than at the scale of individual patches; is directly linked to the interactive effects of patch arrangement, patch stability, and patch quality; and, that invertebrate response to these three factors is modified by the presence of fish predators.We propose three field experiments to test the following specific hypotheses: (1) in stable landscapes (no patch movement), the abundance of stream invertebrates depends on patch arrangement and patch quality (leaf species composition); (2) when patches are not stable, the abundance of invertebrates depends on the interactive effects of patch arrangement and the level of patch stability; and (3) the response of stream invertebrates to patch arrangement, quality, & stability is influenced by the presence of predatory fish. To test the first two hypotheses, we will manipulate patch arrangement and patch stability or leaf quality using repeated measures factorial designs. For the third hypothesis, we will manipulate predator abundance and one landscape attribute at a time (patch arrangement, patch stability, or leaf quality). We will follow changes over time in the abundance of invertebrates at the level of landscapes, although we also will be able to assess variability within and among the individual patches that constitute each landscape.This work has important implications because we are asking if and how changes in landscapes --in terms of patch types and their arrangement and their resource levels -- influence biotic assemblages. Much of the current understanding of biotic responses to spatial landscape features is based primarily on theoretical and empirical work on systems in which the landscape features are fairly stable. Since many systems are highly dynamic -- patches move and patch quality varies temporally -- the type of research proposed here is greatly needed. As in our past grant, this research will be conducted as a collaborative effort between P. Silver at Penn State Erie, an undergraduate institution, and M.A. Palmer at University of Maryland College Park, a large research institution. The PI's, undergraduates, graduate students and a post doctoral associate will collaborate in all phases of the work, thereby providing maximum opportunity for students to participate in high quality research in an atmosphere of intense teamwork and collaboration with workers at a large research campus and a small primarily teaching campus.

在许多生态系统中，占主导地位的生境斑块在其总体质量或资源水平方面经常发生变化。周期性地，栖息地斑块可能被物理破坏或破坏。在这种高度动态的系统中，人们往往认为移动的动物群对生境斑块的排列或其他景观属性没有反应。其基本逻辑是，动物对景观属性的反应将被这种系统的空间和时间变异所掩盖。在这个建议中，我们认为，移动的动物在高度动态的系统，事实上，响应景观属性-特别是补丁的安排。斑块的质量和分布对斑块破坏或资源变化后的种群持续性和物种间的相互作用有很大的影响。在以前的NSF资助的研究中，我们发现，流居住摇蚊和桡足类响应的质量和分布的栖息地（叶）补丁在实验室和现场实验，但我们没有考虑补丁的稳定性，补丁资源（叶物种）组成，或捕食者-猎物的相互作用影响动物区系动态。在这里，我们假设河床中的无脊椎动物丰度在多个斑块的尺度上得到了更好的解释（“景观”）比在单个斑块的规模;直接联系到斑块的安排，斑块的稳定性和斑块质量的相互作用的影响;并且，在本发明中，无脊椎动物对这三个因素的反应会因鱼类捕食者的存在而改变。我们提出了三个野外实验来测试以下具体的假设：（1）在稳定的景观中（无斑块运动），溪流无脊椎动物的丰度取决于斑块的排列和斑块质量（叶种组成）;（2）当斑块不稳定时，溪流无脊椎动物的丰度取决于斑块排列和斑块稳定性水平的交互作用;（3）溪流无脊椎动物对斑块排列、质量和稳定性的响应&受捕食性鱼类的影响。为了检验前两个假设，我们将使用重复测量析因设计来操纵斑块排列和斑块稳定性或叶片质量。对于第三个假设，我们将操纵捕食者的丰度和一个景观属性的时间（补丁安排，补丁的稳定性，或叶质量）。我们将在景观一级跟踪无脊椎动物丰度随时间的变化，尽管我们也将能够评估构成每一景观的单个斑块内部和之间的变异性，这项工作具有重要意义，因为我们要问的是景观的变化-就斑块类型及其排列和资源水平而言-是否以及如何影响生物组合。目前对空间景观特征的生物反应的理解主要是基于景观特征相当稳定的系统的理论和经验工作。由于许多系统是高度动态的-补丁移动和补丁质量随时间变化-这里提出的研究类型是非常必要的。与我们过去的资助一样，这项研究将由宾夕法尼亚州立大学伊利分校的P.银和麻省理工学院的M. A.帕尔默在马里兰州大学帕克分校，一个大型的研究机构。PI的，本科生，研究生和博士后助理将在工作的各个阶段进行合作，从而为学生提供最大的机会，在一个大型研究校园和一个小型主要教学校园的紧张的团队合作和与工人合作的气氛中参与高质量的研究。