The work is still in its infancy but is raising the awareness of pathogens and their important roles in wetland ecosystems. Little work has been done in this area, making our research quite significant.
impact statement issue
Over the past few decades, European common reed, Phragmites australis, has emerged as one of the most important invasive wetland plant species in the U.S. and Great Lakes Region. Populations are found not only in inland freshwater wetlands, but coastal freshwater, brackish, and saltwater wetlands. Although up to 14 native haplotypes are found in wetland plant communities, the invasive haplotype M, believed to be introduced from Europe in the early 1800s, is considerably more competitive than native haplotypes and capable of excluding native Phragmites populations as well as other native and desirable wetland plant species, transforming wetland ecosystems into near monocultures of Phragmites.
impact statement response
We have determined that there are diverse communities of fungal and oomycete communities associated with Phragmites populations in wetlands. Those associated with invasive populations are distinct from pathogen communities associated with native Phragmites populations. This is a first step in understanding the role that pathogens play in plant invasions. This work has been presented to land managers affiliated with the Fish and Wildlife Service, the National Park Service, and others charged with managing wetlands and wetland waterways.
impact statement summary
Our research is designed to explain what makes invasive plants invasive. Our studies utilize Phragmites australis invasions in wetlands as a system to study the nature of plant-soil feedbacks between Phragmites populations and microbial communities associated with seedlings and rhizomes. We hypothesize that invasive populations of Phragmites may stimulate plant pathogenic microbes in the soil during invasions, making native plants more susceptible and less competitive with invaders such as Phragmites. This would subsequently allow invasive plants such as P. sutralis to dominate landscapes.