COLLABORATIVE RESEARCH: Pathogen accumulation and its consequences for invasive plants

非本地物种的入侵是常见和广泛的，但入侵的长期结果尚不清楚。从专门的捕食者和病原体中逃脱，最初可能使引进物种胜过本地物种，但如果新栖息地的捕食者或病原体转向它们，引入物种的优势可能会逆转。或者，攻击引入物种的本地病原体可能会溢出来，感染共生的本地物种，并加剧入侵的影响。该项目将评估病原体积累对入侵物种的生态影响，为宿主-病原体动力学的一般生态学理论提供信息，并提高我们对入侵长期后果的理解。一项实地调查将量化在美国东部森林林下的一种侵略性和广泛的入侵植物——细茎草（Microstegium vimineum）上积累的病原体的流行程度和丰富度。通过采用广泛的时间序列，该研究将显示在一种重要入侵植物上积累的病原体的时间变化、地理范围和物种多样性。在隔离温室环境下进行接种试验，以评估病原菌对微剑菌及其共生原生草生长性能的影响。总之，这些结果将有助于评估病原体在入侵物种上积累并减少种群增长或溢出到竞争的本地物种上并间接促进入侵的假设。引进物种的生物入侵是美国的一个主要环境问题。通过提供促进或抑制入侵因素的新信息，该项目将用于土地管理和恢复工作。研究物种本身在一些东部国家引起了重大关注。研究结果会透过网站和刊物，分发给土地管理者、公众、环境及保育组织。此外，该项目将为本科生和一名博士后研究员提供经验和培训，并为一名早期职业科学家提供研究支持。

Invasions by non-native species are common and widespread, but the long-term outcomes of invasions are unclear. Escape from specialized predators and pathogens may initially enable introduced species to outcompete native ones, but the dominance of introduced species may be reversed if the predators or pathogens in their new habitat switch onto them. Alternatively, native pathogens that attack introduced species might spill back, infect co-occurring native species, and exacerbate the impacts of invasions. This project will evaluate the ecological consequences of pathogen accumulation on invasive species to inform general ecological theory on host-pathogen dynamics and improve our understanding of the long-term outcomes of invasions. A field survey will quantify the prevalence and richness of pathogens that accumulate on stiltgrass, Microstegium vimineum, an aggressive and widespread invader of forest understories in the eastern U.S. By employing a broad chronosequence of sites, the study will show the temporal change, geographical extent, and species diversity of pathogens accumulating on an important invasive plant. Inoculation experiments in quarantined greenhouse environments will be used to evaluate the effects of pathogens on the performance of Microstegium and co-occurring native grasses. Together, these results will serve to evaluate the hypotheses that pathogens accumulate on and reduce population growth of invasive species or spill back onto competing native species and indirectly facilitate invasions.Biological invasions by introduced species are a major environmental problem in the U.S. By providing new information on the factors that promote or inhibit invasions, this project will be of use in land management and restoration efforts. The study species is itself of significant concern in a number of eastern States. Research findings will be disseminated to land managers, the public, and environmental and conservation organizations via a website and publications. In addition, this project will provide experience and training for undergraduate students and a post-doctoral researcher, and research support to an early-career scientist.