Control Processes in a Terrestrial Food Web: Trophic Interactions of a Generalist Predator

这项拟议的研究将在一个知之甚少但至关重要的陆地食物网中调查自上而下和自下而上的控制过程：基于碎屑的森林地面网。狼蛛是一种丰富的多面手捕食者，在整个北美东部落叶森林的落叶群落的食物网中占有中间地位。这个项目通过实验室实验和一系列短期和长期的现场操作实验来研究这个食物链中的控制过程，这些实验旨在揭示水母如何与其上方和下方的营养水平相互作用。%了解食物网的功能对于谨慎管理和保护生态群落至关重要。当前的食物网理论关注的是资源限制和捕食者-猎物相互作用如何影响不同营养水平的物种。中间营养水平的物种密度可能对顶部捕食者或自上而下控制的级联效应敏感，也可能对食物网底部资源水平的变化或底部控制做出反应。这一结果将广泛适用，因为蜘蛛是所有陆地生境中的主要捕食者，而且森林地面食物网内的过程对森林生态系统中的能量流动和养分循环至关重要。

The proposed research will investigate top-down and bottom-up control processes in a poorly understood but critical terrestrial food web: the detritus-based web of the forest floor. The wolf spider Schizocosa oreata, an abundant generalist predator, occupies an intermediate position in food webs of the leaf-litter community of deciduous forests throughout eastern North America. This project investigates control processes in this food web using laboratory experiments and a series of short-term and long term manipulative field experiments designed to reveal how S. oreata interacts with trophic levels above and below it. %%% Understanding how food webs function is critical to prudent management and conservation of ecological communities. Current food-web theory focuses on how resource limitation and predator- prey interactions affect species on different trophic levels. Densities of species at intermediate trophic levels may be sensitive to cascading effects of top predators, or top-down control, and also may respond to changes in resource levels at the bottom of the food web, or bottom control. The results will be broadly applicable because spiders are major predators in all terrestrial habitats, and because processes within the forest-floor food web are critical to energy flow and nutrient cycling in forest ecosystems.