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，主要的栖息地斑块经常随着其整体质量或资源水平而变化。周期性地，栖息地可能会在物理上破坏或破坏。在这种高度动态的系统中，通常认为移动动物动物对栖息地斑块或其他景观属性的布置无反应。潜在的逻辑是，这种系统的空间和时间变化将掩盖对景观属性的动物响应。在此提案中，我们认为，高度动态系统中的移动动物群实际上对景观属性（尤其是补丁安排）响应。斑块中断或资源变化后的种群持久性和物种相互作用可能会受到斑块的质量和布置的很大影响。在先前由NSF资助的研究中，我们发现溪流居住的chironomids和copepods对实验室和现场实验中栖息地（LEAF）斑块的质量和分布做出了反应，但我们没有考虑贴片稳定性，斑块资源（叶子物种）组成或捕食者 - 捕食者相互作用如何影响动物动力学。在这里，我们假设流床中的无脊椎动物丰度在多个斑块（“景观”）的规模上更好地解释了，而不是在单个斑块的规模上。直接与贴片布置，贴片稳定性和贴片质量的互动效果联系在一起；而且，对这三个因素的无脊椎动物反应通过鱼类捕食者的存在来改变。我们提出了三个现场实验来检验以下特定假设：（1）在稳定的景观（无斑块运动）中，溪流无脊椎动物的丰度取决于斑块布置和斑块质量质量（叶子种类）； （2）当斑块不稳定时，无脊椎动物的丰度取决于斑块布置的互动效应和斑块稳定性的水平； （3）无脊椎动物对斑块排列，质量和稳定性的反应受掠食性鱼的存在影响。为了检验前两个假设，我们将使用重复测量的阶乘设计来操纵斑块布置和斑块稳定性或叶片质量。对于第三个假设，我们将一次操纵捕食者丰度和一个景观属性（贴片布置，斑块稳定性或叶片质量）。尽管我们还将能够评估构成每个景观的单个贴片内部和之间的可变性，但我们将随着时间的流逝而随着时间的流逝而随着时间的流逝而进行变化。这项工作具有重要的含义，因为我们询问景观的变化是否以及如何变化 - 贴片类型及其资源及其资源水平及其资源水平 - 影响生物组件 - 影响生物组件。当前对生物对空间景观特征的生物反应的理解主要基于理论和经验工作，这些系统对景观特征相当稳定。由于许多系统是高度动态的 - 贴剂移动和贴片质量在时间上有所不同 - 非常需要此处提出的研究类型。与我们过去的赠款一样，这项研究将是作为本科机构Penn State Erie的P. Silver和Maryland College Park的M.A. Palmer（一家大型研究机构）进行的合作努力。 PI的本科生，研究生和博士后副学士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，让学生参加高质量的研究，以在团队合作和与工人合作的氛围中与大型研究校园和小型研究校园合作。