Career: Environmental Heterogeneity and the Relative Roles of Top-Down and Bottom-Up Forces in Oak Herbivore Communities

职业：环境异质性以及橡树食草动物群落中自上而下和自下而上的力量的相对作用

• 批准号: 9527522
• 负责人: Mark Hunter
• 金额: $ 12万
• 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: 1996
• 资助国家: 美国
• 起止时间: 1996-02-01 至 2000-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9527522&HistoricalAwards=false
• 关键词: Career; Environmental; Heterogeneity; Relative; Roles

9527522 Hunter Most ecologists agree that populations of herbivores are influenced by both the availability of suitable plant food and by the actions of their natural enemies. There is no consensus, however, on how the relative power of these two processes varies in different environments. This project combines experimental approaches and field sampling to assess changes in the relative importance in food quality and natural enemies on populations of insect herbivores that feed on oak trees. The quality of oak leaves will be manipulated by fertilization of trees in a plantation, and natural enemies will be excluded from a subset of the trees. Sampling will determine whether insect populations respond more to changes in food quality than to changes in predation pressure. The results from the oak plantation will be compared with a natural field site, the Coweeta Long-Term Ecological Research Site, where oak trees grow along a gradient in elevation. The results will add to our understanding of the environmental conditions under which predators or food quality dominate populations of herbivores. Humans are interested in managing populations of many kinds of herbivores. Insect pest of fields and forests, and mammals such as deer and caribou, are among the herbivores that we seek to control because of their effects on food production and recreation. Judicious management of herbivore populations requires understanding of the factors that influence their population ecology. The results of this project will help determine the circumstances under which biological control or hunting will aid or hinder management goals.

9527522猎人大多数生态学家都同意，草食动物的种群既受到适当植物食物的可获得性的影响，也受到它们的天敌的行动的影响。然而，对于这两个进程在不同环境中的相对权力如何变化，还没有达成共识。该项目结合了实验方法和实地采样，以评估食物质量和天敌对以橡树为食的食草昆虫种群的相对重要性的变化。橡树叶的质量将通过在种植园中对树木进行施肥来控制，天敌将被排除在树木的子集之外。抽样将决定昆虫种群是否更多地对食物质量的变化做出反应，而不是对捕食压力的变化做出反应。来自橡树种植园的结果将与自然野外地点Coweeta长期生态研究地点进行比较，在那里橡树沿着海拔梯度生长。这一结果将增加我们对捕食者或食物质量主导草食动物种群的环境条件的理解。人类对管理多种食草动物的种群很感兴趣。田野和森林的害虫，以及哺乳动物，如鹿和驯鹿，是我们寻求控制的食草动物之一，因为它们对食物生产和娱乐有影响。对食草动物种群的明智管理需要了解影响其种群生态的因素。该项目的结果将有助于确定在何种情况下生物防治或狩猎将有助于或阻碍管理目标。