Effects of Consumers on Spatial Heterogeneity in Their Resources in Streams

尽管最近的理论和实证研究表明，空间异质性对人口和社区的动态产生了深远的影响，但对消费者对其资源的空间异质性的影响的研究却很少。在这项研究中，PI将应用空间统计来分析操纵食草动物、捕食者和营养物的大型实验，以量化消费者和营养物对河流中低营养水平空间异质性的影响。该指数还将量化消费者对其资源不完整性的不同方面的分配反应。该设计结合了预算方法，这样我们就可以确定直接捕食者效应（猎物迁移与捕食者消耗）的机制，以及多营养水平的相互作用，这样PI就可以检查不同捕食者（鳟鱼，石蝇）对猎物（无脊椎动物）和猎物资源（藻类）的直接和相互作用影响。辅助调查将确定自然溪流中消费者及其资源的斑块和重叠程度。本研究将以包含空间异质性的开放系统的营养链模型为指导。该研究首次明确使用空间统计来解决消费者对其资源空间异质性的影响。这种方法将极大地扩展我们对自上而下的力量如何在空间明确的背景下影响社区结构和动态的理解。

9407591 Cooper Although recent theoretical and empirical investigations have indicated the profound influence of spatial heterogeneity on the dynamics of populations and communities, there have been few examinations of the effects of consumers on spatial heterogeneity of their resources. In this research, the PI will apply spatial statistics to the analysis of large experiments manipulating grazers, predators, and nutrients to quantify the effects of consumers and nutrients on spatial heterogeneity in lower trophic levels in streams. The PI will also quantify the distributional responses of consumers to different aspects of patchiness in their resources. The design incorporates both a budget approach, so that we can determine the mechanisms responsible for direct predator effects (prey emigration vs predator consumption), and multi-trophic level interactions, so that the PI's can examine the direct and interactive effects of different predators (trout, stoneflies) on their prey (invertebrates) and their prey's resources (algae). Subsidiary investigations will determine scales of patchiness and overlap in consumers and their resources in natural streams. This research will be guided by trophic chain models for open systems that incorporate spatial heterogeneity. %%% The proposed research is the first to explicitly use spatial statistics to address the effects of consumers on the spatial heterogeneity of their resources. This approach will greatly expand our understanding of how top-down forces effect community structure and dynamics within a spatially-explicit context.