Rare-species advantage: consequences of phylogenetic and numerical rarity of hosts for disease pressure and pathogen communities

该奖项是根据2009年美国复苏和再投资法案(公法111-5)资助的。当地稀有物种预计将具有生存优势，因为稀有物种降低了它们受到病原体破坏的风险。这种“稀有物种优势”可能有助于维持自然系统中的植物多样性，并解释引进的植物物种是如何成为入侵杂草的。如果只有很少的个体存在，植物物种被认为是稀有的；这假设病原体专门针对单个物种。事实上，大多数病原体都能感染各种不同的宿主，密切相关的物种更有可能共享同一病原体。因此，稀有性不是简单的物种密度(数量稀有性)的函数，而是与病原体相同的物种的综合密度的函数。PI将评估系统发育和丰度在加州中部海岸七个植物群落稀有物种优势中的相对重要性。他们将测量疾病流行率、病原体的宿主范围以及病原体在不同宿主上繁殖的能力。结果将与当地寄主丰度和寄主物种之间的关联度进行比较，这是首次尝试评估植物群落的整体结构如何影响群落中每个物种遭受的疾病数量。该项目将为具有分子生物学背景的博士后提供生态学培训，并培训分子和生态学研究方面的研究生和本科生。对加州大学洛杉矶分校森林生态研究小区的持续支持将有助于扩大教育和研究的协同效应。这项研究将为管理植物和植物产品国际贸易的政策提供参考。最后，这一结果将为引进物种是否系统地逃避天敌提供新的线索，这一观点在杂草的生物防治和引进物种政策的其他方面具有很大影响。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Locally rare species are expected to have a survival advantage because rarity reduces their risk of damage from pathogens. This "rare-species advantage" may help maintain plant diversity in natural systems and explain how introduced plant species become invasive weeds. Plant species are considered rare if few individuals are present; this assumes pathogens are specialized on individual species. In fact, most pathogens are able to infect a variety of different hosts and closely related species are more likely to share a pathogen. Thus rarity is not simply a function of species density (numerical rarity), but of the combined density of species with which it shares a pathogen. The PIs will evaluate the relative importance of phylogeny and abundance in the rare-species advantage in seven plant communities along the Central Coast of California. They will measure disease prevalence, host ranges of pathogens, and the ability of the pathogens to reproduce on different hosts. Results will be compared to local host abundance and relatedness between host species, in the first attempt to evaluate how the overall structure of a plant community affects the amount of disease suffered by each species in the community. The project will provide ecological training for a postdoctoral fellow with a background in molecular biology, as well as train graduate and undergraduate students in both molecular and ecological research. Continued support for the UCSC Forest Ecology Research Plot will help extend substantial educational and research synergies. This research will inform policies that regulate international trade of plants and plant products. Finally, the results will shed new light on whether introduced species systematically escape natural enemies, an idea that is highly influential in the biological control of weeds and other aspects of introduced species policy.