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。当地稀有物种预计具有生存优势，因为稀缺性降低了它们受到病原体损害的风险。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，并解释引入的植物物种如何成为入侵杂草。如果存在很少的个体，则认为植物物种是稀有的；这假定病原体是专门针对个别物种的。事实上，大多数病原体能够感染各种不同的宿主，而密切相关的物种更有可能共享一种病原体。因此，稀有性不仅仅是物种密度的函数（数量稀有性），而且是与它共享病原体的物种的综合密度的函数。该项目将评估加利福尼亚中部海岸7个植物群落中系统发育和稀有物种优势丰度的相对重要性。它们将测量疾病的流行程度、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亲缘关系进行比较，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，并培养分子和生态学研究方面的研究生和本科生。继续支持加州大学圣迭戈分校森林生态研究地块将有助于扩大实质性的教育和研究协同效应。这项研究将为管理植物和植物产品国际贸易的政策提供信息。最后，研究结果将揭示引入物种是否系统性地逃避天敌，这一观点在杂草的生物控制和引入物种政策的其他方面具有重要影响。

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.