EAPSI: Nitrogen Cycle Responses to Increasing Presence of Parasitic Mistletoes in Australian Eucalypt Forests

随着土地管理的变化，澳大利亚的桉树林越来越多地被槲寄生淹没。槲寄生是一种寄生植物，它会减少宿主桉树的生长，但也会促进森林中鸟类多样性的增加，导致人们对槲寄生如何影响森林功能和生产力的看法相互矛盾。评估如何生物重要的营养物质，如氮，通过森林循环响应槲寄生寄生可以深入了解森林的健康和功能。 氮过程中的变化所造成的增加丰富的槲寄生可能会对森林健康和全球气候的影响，并可能告知未来的土地管理决策在澳大利亚林地和其他地方。该项目是与澳大利亚西悉尼大学霍克斯伯里环境研究所的Elise Pendall博士合作进行的，将探讨槲寄生在桉树林地氮循环中的作用。Pendall博士是一位著名的生态系统生态学家，她在生态系统扰动下的土壤地球化学循环方面的研究工作而闻名。产于澳大利亚坎伯兰平原的纤维瘤。 据推测，富含氮的槲寄生垃圾可以增加分解率，并作为一氧化二氮（N2O）排放量增加的基质，一种强大的温室气体。本研究将探讨氮循环的各种组分的速率如何响应于A比例的增加。桉树林中的miquelii凋落物。通过分析植物凋落物的质量和数量、处理植物凋落物及其含氮组分的土壤微生物活性以及森林土壤N_2O排放量，确定了森林土壤中A. miquelii的土壤过程和氮循环在以前的氮贫系统。这个奖项，根据东亚和太平洋夏季研究所计划，支持美国研究生的夏季研究，是由NSF和澳大利亚科学院共同资助。

Australian eucalypt forests are increasingly inundated with mistletoes, in large response to changes in land management. Mistletoes are parasitic plants that reduce the growth of their host eucalyptus trees but also promote increased bird diversity in forests, resulting in conflicting opinions about how mistletoes affect forest function and productivity. Assessing how biologically-important nutrients, such as nitrogen, cycle through forests in response to mistletoe parasitism may give insight into forest health and function. Changes in nitrogen processes resulting from increasing abundance of mistletoe will likely have ramifications for forest health and global climate, and may inform future land management decisions in Australian woodlands and elsewhere. This project, conducted in collaboration with Dr. Elise Pendall at the Hawkesbury Institute for the Environment at Western Sydney University in Australia, will explore the role of mistletoe for nitrogen cycling in eucalyptus woodlands. Dr. Pendall is a renowned ecosystem ecologist known for her work in biogeochemical cycling in response to ecological disturbances.Relatively little is known about the impacts of Amyema miquelii mistletoe litter on decomposition, nitrification, and denitrification processes in woodlands dominated by Eucalyptus moluccana and E. fibrosa found in Cumberland Plain, Australia. Presumably, nitrogen-rich mistletoe litter could increase decomposition rates and serve as a substrate for increased emissions of nitrous oxide (N2O), a potent greenhouse gas. This study will explore how rates of various components of nitrogen cycling respond to increasing proportions of A. miquelii litter in Eucalyptus forests. By analyzing the quality and quantity of litterfall from plants, the soil microbial activity responsible for processing plant litter and its nitrogenous components, and the emissions of N2O from forest soils, the researcher will determine the increasing contribution of A. miquelii to soil processes and nitrogen cycling in previously nitrogen-poor systems.This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by NSF and the Australian Academy of Science.