COLLABORATIVE RESEARCH: Pathogen accumulation and its consequences for invasive plants

University Of Florida, Gainesville FL

Investigators

Abstract

Invasions by non-native species are common and widespread, but the long-term outcomes of invasions are unclear. Escape from specialized predators and pathogens may initially enable introduced species to outcompete native ones, but the dominance of introduced species may be reversed if the predators or pathogens in their new habitat switch onto them. Alternatively, native pathogens that attack introduced species might spill back, infect co-occurring native species, and exacerbate the impacts of invasions. This project will evaluate the ecological consequences of pathogen accumulation on invasive species to inform general ecological theory on host-pathogen dynamics and improve our understanding of the long-term outcomes of invasions. A field survey will quantify the prevalence and richness of pathogens that accumulate on stiltgrass, Microstegium vimineum, an aggressive and widespread invader of forest understories in the eastern U.S. By employing a broad chronosequence of sites, the study will show the temporal change, geographical extent, and species diversity of pathogens accumulating on an important invasive plant. Inoculation experiments in quarantined greenhouse environments will be used to evaluate the effects of pathogens on the performance of Microstegium and co-occurring native grasses. Together, these results will serve to evaluate the hypotheses that pathogens accumulate on and reduce population growth of invasive species or spill back onto competing native species and indirectly facilitate invasions. Biological invasions by introduced species are a major environmental problem in the U.S. By providing new information on the factors that promote or inhibit invasions, this project will be of use in land management and restoration efforts. The study species is itself of significant concern in a number of eastern States. Research findings will be disseminated to land managers, the public, and environmental and conservation organizations via a website and publications. In addition, this project will provide experience and training for undergraduate students and a post-doctoral researcher, and research support to an early-career scientist.