Dissertation Research: Invasion of Non-Indigenous Grasses into a Hawaiian Dry Woodland and the Ecosystem Consequences of Changes in Community Structure

9700737 D'Antonio该提案研究了生物入侵、群落组成变化和生态系统过程改变之间的联系，这些变化有助于全球氮（N）循环的变化。拟议的研究的目标是确定夏威夷季节性山地林地中的非土著草改变生态系统N循环的机制，以及这些变化如何影响植物生长和生态系统N积累的N可用性。插入草的N循环速率增加，损失率降低的假设将进行测试，通过比较N动态之间的未燃烧的林地与草删除，未燃烧的林地与草，和燃烧的网站，草为主。矿物硝化作用，土壤微量气体排放，植物生产和生态系统N分配使用15 N示踪剂的测量将。这项研究提供了一个独特的社区和生态系统过程之间的联系，解决的作用，一个新的增长形式在生态系统N动态。这项研究将区分机制，通过草的影响N动态，它将同时比较物理，化学和竞争的生长形式对养分动态的影响。本研究还讨论了入侵物种的生长形式和当地资源供应率之间的反馈，这可能会影响竞争性相互作用，并最终影响入侵者的成功。

9700737 D'Antonio This proposal examines the links between biological invasions, changes in community composition, and alteration of ecosystem processes that contribute to changes in the global nitrogen (N) cycle. The objectives of the proposed research are to define mechanisms by which non-indigenous grasses in Hawaiian seasonal submontane woodlands have altered ecosystem N cycling and how these changes affect N availability to plant growth and ecosystem N accumulation. The hypothesis that insertion of grasses increases rates of N cycling and decreases rates of loss will be tested by comparing N dynamics among unburned woodland with grasses removed, unburned woodland with grasses, and burned sites that are grass dominated. Measurements of mineral nitrification, soil trace gas emissions, plant production, and ecosystem N partitioning using an 15N tracer will be made. This research provides a unique link between community and ecosystem processes by addressing the role that a new growth form plays in ecosystem N dynamics. This research will differentiate mechanisms through which grasses effect N dynamics, and it will simultaneously compare the physical, chemical, and competitive effects of a growth form on nutrient dynamics. This research also addresses feedbacks between growth form of invading species and local rates of resource supply that may influence competitive interactions and ultimately, the success of the invaders.