Dissertation Research: Nutrient Use Efficiency in Simplified Tropical Ecosystems

9623969 Ewel简化热带生态系统中的养分利用效率。 植物利用养分的效率是一个主题，它将许多尺度上的生理过程结合在一起-从叶子到植物，再到整个生态系统。叶片和植物水平上养分利用效率的差异是否可以扩大，以预测生态系统水平上的养分利用效率？将在一系列简化的热带生态系统中以不同的尺度调查养分利用效率：树木单一栽培、树木和一种非常不同的生命形式-大型多年生单子叶植物的混合栽培。养分利用效率将在叶一级计算为每单位养分含量的最大潜在光合速率;在植物一级计算为相对于养分吸收的总生物量;在生态系统一级计算为相对于养分供应的生物量生产。这项研究将提供一个机会，比较不同规模和不同生命形式的营养利用效率。了解叶片和植物水平的养分利用效率与生态系统养分利用之间的反馈，将有助于深入了解生物多样性的功能作用。它还将提供一个强有力的工具，使退化的土地得以恢复，并设计出有效保护养分的土地使用制度。

9623969 Ewel Nutrient use efficiency in simplified tropical ecosystems. The efficiency with which plants use nutrients is a theme that unites physiological processes at many scales - from leaves, to plants, to whole ecosystems. Can differences in nutrient use efficiency at the leaf and plant level be scaled up to predict nutrient use efficiency at the ecosystem level? Nutrient use efficiency will be ilvestigated at different scales in a series of simplified tropical ecosystems: tree monocultures, and polycultures of trees and a very different life form - large, perennial monocots. Nutrient use efficiency will be calculated at the leaf level, as the maximum potential photosynthetic rate per unit nutrient content; at the plant level, as total biomass produced relative to nutrient uptake; and at the ecosystem level, as biomass production relative to nutrient supply. The study will provide an opportunity to compare nutrient use efficiency across scales, and across life forms. Understanding feedbacks between nutrient use efficiency at the leaf and plant level, and ecosystem nutrient use, will provide insight into the functional role of biodiversity. It will also provide a powerful tool in enabling restoration of degraded lands, and design of land use systems that are effective at nutrient conservation.