Effects of Plant Functional Identity on Ecosystem Nitrogen Retention Following Fire

植物功能特性对火灾后生态系统氮保持的影响最近的变暖趋势和人类活动的增加导致了北美北方森林火灾事件的增加。北方生物群的森林生产力通常受到氮(N)有效性的限制，而火灾频率的增加会增加N通过燃烧和火灾后损失到大气和水中的机会从生态系统中损失的机会。了解对火灾后这些氮素损失的控制，对于预测火灾频率增加对森林生产力和碳循环的长期后果非常重要。在这项提议中，研究人员假设，最初在被烧毁的生态系统中定居的植物物种的功能特征将控制生态系统积累碳的能力，从而在火灾后保留氮。研究人员将通过对1999年6月烧毁的北方黑云杉森林中氮素损失的研究来验证这一假设。这种研究方法将需要在生态系统范围内添加一种可追踪的稳定氮同位素，并结合植物定居的实验操作。

Abstract00-75669MackEffects of plant functional identity on ecosystem nitrogen retention following fireRecent warming trends and increased human activities have led to documented increases in fire occurrence in North American boreal forests. Forest productivity in the boreal biome is generally limited by the availability of nitrogen (N), and increased fire frequency causes increased opportunity for N to be lost from the ecosystem via combustion and post-fire losses to the atmosphere and water. Understanding controls over these N losses following fire is important for predicting the long-term consequences of increased fire frequency for forest productivity and carbon cycling. In this proposal, the investigators hypothesize that the functional traits of the plant species that initially colonize burned ecosystems will control the ability of the ecosystem to accumulate carbon and thus retain N following fire. The researchers will test this hypothesis with a study of N loss in a boreal black spruce forest that burned in June 1999. The research approach will entail an ecosystem-scale addition of a stable N isotope that can be tracked, combined with experimental manipulation of plant colonization.