Do Pathogens and Herbivores Regulate Plant Populations in Their Native and Introduced Ranges? A Test of the Enemy Release Hypothesis

入侵植物（侵略性的，非本地杂草）每年仅在美国就给农业和牧场造成数十亿美元的损失。 入侵还威胁到许多本地物种的保护，并对生物多样性构成威胁。 这个项目将测试为什么一些植物是入侵的主要假设之一：敌人释放假设（ERH）。 ERH指出，当一种植物被引入一个新的栖息地时，它比本地植物生长得更好，因为它的敌人（食草动物和病原体）不存在于新的栖息地。 ERH的一个关键的未经检验的假设是，食草动物和病原体减少人口规模在本地范围，但不是在入侵范围。 敌人清除实验和实地调查将被用来测试敌人是否真的调节植物种群的六个草种，他们是本地的（瑞士）和他们是入侵的（俄勒冈州）。 该项目将为学生提供财政支持，并将纳入PI教授的两门课程。 将通过培训志愿人员和举办公开讲座，进一步向公众宣传。 对入侵物种的研究引起了联邦机构和保护团体的极大兴趣。我们一直在与来自以下机构的工作人员合作：芬利国家野生动物保护区、自然保护区、莱恩县公园、陆军工程兵团、BLM和西尤金湿地合作伙伴。 结果将分发给这些机构，并在同行审查的出版物中公布。

Invasive plants (aggressive, non-native weeds) cause several billion dollars per year in losses to agriculture and rangelands in the United States alone. Invasions also threaten the conservation of many native species and are a threat to biodiversity. This project will test one of the major hypotheses for why some plants are invasive: The enemy release hypothesis (ERH). The ERH states that when a plant is introduced to a new habitat, it grows better than native plants do because its enemies (herbivores and pathogens) are not present in the new habitat. A key untested assumption of the ERH is that herbivores and pathogens decrease population size in the native range but not in the invasive range. Enemy removal experiments and field surveys will be used to test whether enemies actually regulate plant populations for six grass species where they are native (Switzerland) and where they are invasive (Oregon). This project will provide financial support for students and will be integrated into two courses taught by the PI. Public outreach will be furthered through the training of volunteers and through public lectures. Work on invasive species is of great interest to federal agencies and conservation groups. We have been working with staff from the following: Finley National Wildlife Refuge, the Nature Conservancy, Lane County Parks, Army Corps of Engineers, BLM and the West Eugene Wetland Partners. Results will be disseminated to these agencies as well as in peer reviewed publications.