CAREER: Climate and connectivity as drivers of pathogen dynamics within and between urban plant populations

Urban life presents many challenges for animals and plants. Roads and buildings divide the landscape into small patches of vegetation in parks, yards, and gardens. Species in those habitats are in close contact with humans and vehicles. Cities also produce and trap more heat than surrounding areas. Habitat fragmentation, human activity, and warming can each impact the risk of disease for organisms. However, it is unknown how these factors alter the spread of disease in urban systems. This knowledge gap hinders prediction and management of disease for urban wildlife and plants. To fill this gap, the project will use mathematical models, field studies, and experiments. In models, disease spread will be simulated under urbanization and climate scenarios. Modeling will also be part of projects in an undergraduate Disease Ecology course. Field studies and experiments will focus on common plants and their fungal pathogens. Diverse undergraduate and high school students will participate in data collection on climate and plant health across St. Louis, Missouri. In addition, K-12 students in an urban public school district will engage with an experiment in school gardens. Data collection and analysis activities will be aligned to school STEM curriculum. Urbanization involves habitat fragmentation and warming that can impact the frequency and outcome of host-pathogen encounters. Yet we currently lack a framework for predicting change in disease prevalence with variation in climate and population connectivity across urbanization gradients. The proposed research will resolve how macroclimate, microclimate, and habitat connectivity shape urbanization-disease relationships. Flexible metapopulation models will be used to study the influence of population connectivity and multiple scales of climate variation on disease prevalence across theoretical cities and their surroundings. The modeling will be incorporated into a new course-based undergraduate research experience. In laboratory and field studies, microclimate effects on plant host susceptibility and foliar pathogen infectivity will be quantified across an urbanization gradient. Pathogen genotypes will be analyzed to determine if more urban plant populations have greater pathogen survival overwinter or greater rates of between-population dispersal during the growing season. The empirical work will be integrated with K-12 STEM outreach and field research experiences for high school and undergraduate students. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.