Top-Down and Bottom-Up Effects on Herbivores: Nutrient Availabilty and the Trophic Interactions of Insects on Oak

对草食动物的自上而下和自下而上的影响：橡树上的养分利用率和昆虫的营养相互作用

• 批准号: 9906366
• 负责人: Mark Hunter
• 金额: $ 7万
• 依托单位: University of Georgia Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-15 至 2002-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9906366&HistoricalAwards=false
• 关键词: Top; Down; Bottom; Up; Effects

Hunter9906366That top-down and bottom-up forces interact in various ways to the control basic features of ecosystems is widely appreciated but the factors that control the balance of these forces is far from completely understood. This project will continue an earlier three-year experimental study of oak herbivore populations in which nutrients and bird-predation pressure had been manipulated in a factorial design. Initial results had differed from previous terrestrial experimental studies and the present project will seek to explain those differences among studies by considering different size classes of trees. It will specifically test whether top-down effects occur on large but not small saplings, the relative strength of top-down forces with increasing nutrient availability, and the existence of a time lag in the generation of top-down forces on herbivores from the arthropod predator community. This study will contribute to the understanding of the trophic dynamics of terrestrial ecosystems. It will also provide an opportunity for numerous undergraduate students to gain a substantial research experience.

人们普遍认识到，自上而下和自下而上的力量以各种方式相互作用，以控制生态系统的基本特征，但控制这些力量平衡的因素还远未完全了解。该项目将继续之前为期三年的橡树草食动物种群实验研究，其中营养和鸟类捕食压力在因子设计中被操纵。初步结果与以前的陆地实验研究不同，本项目将设法通过考虑不同大小的树木类别来解释这些研究之间的差异。它将专门测试自上而下的影响是否发生在大而不是小的树苗上，随着养分可用性的增加，自上而下的力量的相对强度，以及在节肢动物捕食者群落中自上而下的力量对食草动物的产生是否存在时间滞后。这项研究将有助于理解陆地生态系统的营养动力学。它也将为众多本科生提供获得大量研究经验的机会。