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

拟议的研究将调查一个鲜为人知但至关重要的陆地食物网的自上而下和自下而上的控制过程：以碎屑为基础的森林地面网。Schizocosa oreata狼蛛是一种丰富的多面手捕食者，在北美东部落叶群落的食物网中处于中间位置。本项目通过实验室实验和一系列短期和长期的野外操作实验来研究这一食物网的控制过程，这些实验旨在揭示oreata是如何与上面和下面的营养水平相互作用的。了解食物网如何运作对谨慎管理和保护生态群落至关重要。目前的食物网理论主要关注资源限制和捕食者-猎物相互作用如何影响不同营养水平的物种。中等营养水平的物种密度可能对上层捕食者的级联效应或自上而下的控制敏感，也可能对食物网底部资源水平的变化或底部控制作出反应。这项研究结果具有广泛的适用性，因为蜘蛛是所有陆地栖息地的主要捕食者，而且森林地面食物网的过程对森林生态系统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.