DISSERTATION RESEARCH: Climate-mediated effects of pathogens on plant communities

虽然疾病对农作物和牲畜的有害影响是众所周知的，但科学家们才刚刚开始认识到疾病对野生动植物的重要性。除了杀死受感染的个体和减少动植物种群外，疾病还可以影响生态群落的物种组成。例如，当物种竞争资源，如食物和水，也共享一种疾病时，疾病可以阻止更好的竞争对手占主导地位，并允许物种共存。或者，这种疾病可以更快地消灭竞争力较弱的物种。这项研究将调查一种杀死草籽的真菌疾病是否有助于美国西部山间有害的外来草种cheatgrass的入侵和统治。这种入侵的草会破坏牧场，引发火灾，但也会传播一种真菌疾病，杀死本地草和欺骗草的种子。该实验将测量犹他州田间种群的疾病，并使用数学模型计算其对千草入侵和本土植物持久性的影响。这项研究还将控制秋季降雨量，以确定该疾病的影响是否取决于气候条件。这项研究将提高对疾病对有害草入侵影响的科学认识。研究结果将为管理决策提供信息，这些管理决策基于使用疾病来对抗入侵草。扩大对野生动物疾病影响的科学认识也将有助于保护其他利益群体，如热带森林和珊瑚礁鱼类。除了其科学影响，该项目将促进本科生的研究经验。这项研究还将纳入本科课程的教材。该项目已经为五名本科生（四名女性）提供了研究经验，并将导致一名女性数学生物学家完成博士论文，这是该领域代表性不足的少数群体。

Although the harmful effect of disease on agricultural crops and livestock is well-known, scientists are just beginning to recognize the importance of disease in wild plants and animals. In addition to killing infected individuals and reducing populations of plants and animals, diseases can affect the species composition of ecological communities. For example, when species compete for resources, such as food and water, and also share a disease, the disease can prevent the better competitor from dominating and allow the species to coexist. Alternatively, the disease could wipe out the less competitive species more quickly. This study will investigate whether a fungal disease that kills grass seeds is contributing to the invasion and dominance of a harmful exotic grass species, cheatgrass, in the U.S. Intermountain West. The invasive grass degrades rangeland and promotes fire, but also spreads a fungal disease that kills seeds of native grasses as well as cheatgrass. The experiment will measure the disease in field populations in Utah, and calculate its impact on cheatgrass invasion and native plant persistence using mathematical models. The study will also manipulate fall rainfall to determine whether the disease's impacts depend on climate conditions.This research will improve scientific understanding of the effect of disease on a harmful grass invasion. The results will inform management decisions based on using disease to combat the invasive grass. Expanding scientific understanding of the impacts of wildlife disease will also aid conservation of other communities of interest such as tropical forests and coral reef fishes. In addition to its scientific impacts, this project will promote research experience for undergraduates. The research will also be incorporated into teaching materials for undergraduate courses. This project has already provided research experience for five undergraduates (four female), and it will result in the completion of a doctoral dissertation by a female mathematical biologist, an underrepresented minority in this field.