LTREB RENEWAL: The population dynamics of forest understory invasion: mechanistic experiments with generalist herbivores, natives, and invaders

入侵物种威胁着当地生态系统的完整性，每年在美国造成数十亿美元的经济损失。这一长期项目将确定允许某些物种入侵，允许某些群落入侵，而允许其他物种不入侵的机制。这是公共科学家在研究和管理方面合作伙伴关系的一个令人兴奋的例子，因为调查人员与当地和地区官员合作保护他们的自然区域，向这些地区的公众游客推广，并开发和评估一次虚拟实地旅行，让无法直接访问研究现场的中学生参与。该项目将继续为本科生和研究生提供培训，特别强调从实地生态学代表性不足的群体中招收学生。该奖项支持一个十年项目的第二阶段，该项目旨在了解大蒜芥菜入侵的人口和社区层面的动态。调查员将收集七种重点物种的生命频率数据，包括三种鹿喜欢的本土多年生草本植物，两种鹿不喜欢的本土草本多年生植物，一种原生冬季一年生植物，以及高度入侵的大蒜芥末。生命表反应实验将包括两个完全交叉的处理：要么是开放的，要么是用栅栏隔开的，以排除鹿，以及在有大蒜芥末和移除大蒜芥末之间划分的地块。人口矩阵预测分析和积分预测模型分析将用于预测实验产生的鹿和入侵者情景下的种群增长率和重点物种的长期命运。人口统计学分析将通过探索入侵成功的假设机制的实验来补充。该项目第一阶段的结果表明，大蒜芥菜释放的化学物质通过破坏本地植物-菌根互惠关系来抑制局部本地植物的生理功能和碳贮量。在第二阶段，将比较有关四种处理植物生理状态的更多数据。对局部植物的瞬时光合作用和蒸腾速率、气孔导度和荧光测量将有助于深入了解碳胁迫作为一种本地衰退和入侵控制的机制。

Invasive species threaten the integrity of native ecosystems and cause billions of dollars in economic losses in the US annually. This long-term project will identify the mechanisms that allow some species to be invasive, and some communities to be invaded, while others are not. It is an exciting example of a public-scientist partnership in research and management, as the investigator works collaboratively with local and regional officials on the conservation of their natural areas, outreach to public visitors of these areas, and developing and assessing a virtual field trip that engages middle school students who are unable to visit the research site directly. The project will continue to provide training for undergraduate and graduate students, with a particular emphasis on recruiting students from groups under-represented in field ecology. This award supports Phase II of a decadal project to understand the population- and community-level dynamics of invasion by garlic mustard. The investigator will collect vital rate data on seven focal species, including three native herbaceous perennials that are highly palatable to deer, two native herbaceous perennials unpalatable to deer, a native winter annual, and the highly invasive garlic mustard. A Life Table Response Experiment will include two fully crossed treatments: plots are either open or fenced to exclude deer, and plots divided between garlic mustard presence and its removal. Demographic matrix projection analyses and Integral Projection Models analyses will be used to project population growth rates and the long-term fates of focal species under the deer and invader scenarios generated by the experiment. Demographic analyses will be complemented by experiments exploring the hypothesized mechanisms of invasion success. Results from Phase I of this project indicated that chemicals released by garlic mustard suppress physiological function and carbon storage of the focal natives by disrupting the native plant-mycorrhizal mutualism. In Phase II, additional data on the physiological status of plants the four treatments will be compared. Instantaneous photosynthetic and transpiration rates, stomatal conductance and fluorometric measurements of focal plants will provide insights into carbon stress as a mechanism of native decline and invader domination.