DISSERTATION RESEARCH: The role of seedling pathogens in temperate forest recuitment

长期以来，人们一直怀疑植物病原体通过控制幼苗的生长和存活来维持树木的多样性，但对未管理的温带森林中的病原体知之甚少。为了更好地了解森林病原体如何影响树种的共存，在两个北卡罗来纳州森林中种植树苗的混合种地块。经常监测幼苗死亡率，并使用培养和基于DNA的方法从死亡幼苗中鉴定病原体。同时收集有关树木人口（幼苗死亡率，成年密度）和环境条件（光照，土壤湿度）的其他相关数据。这些数据相结合，以确定这些森林中的主要真菌和卵菌病原体，其分布的环境因素，以及它们在塑造森林群落中发挥的作用。 该项目提供了深入了解植物病原体的时空动态，这可能有助于减少其在自然和管理的森林生态系统中的负面影响。这些信息具有经济意义，可用于改善森林或恢复区种植和收获的密度、位置和时间的决策，从而制定新的疾病管理策略，促进提高植物生产力和可持续性。这项研究有可能加强目前的管理实践，并告知模型，预测未来的树木分布与全球变化。该项目还通过让本科生和高中生担任勤工俭学助理和暑期研究技术员，促进外联、教学和培训。

Plant pathogens have long been suspected to play a role in maintaining tree diversity by controlling seedling growth and survival, yet relatively little is known about pathogens in unmanaged temperate forests. To better understand how forest pathogens influence coexistence of tree species, mixed-species plots of tree seedlings were planted in two North Carolina forests. Seedling mortality is monitored frequently, and pathogens are identified from dead seedlings using cultural and DNA-based methods. Other relevant data about tree demography (seedling mortality, adult density) and environmental conditions (light, soil moisture) are collected simultaneously. These data are combined to identify the major fungal and oomycete pathogens in these forests, the environmental factors underlying their distributions, and the role they play in shaping forest communities. This project provides insight into understanding the spatial and temporal dynamics of plant pathogens, which may help to reduce their negative impact in natural and managed forest ecosystems. This information is of economic significance and can be used to improve decisions about the density, location, and timing of planting and harvesting in forests or restoration areas such that new disease management strategies can be developed that promote increased plant productivity and sustainability. This study has the potential to enhance current management practices and to inform models that predict future tree distributions associated with global change. This project also promotes outreach, teaching and training by involving undergraduate and high school students as work-study assistants and summer research technicians.