When one thinks of ecological communities and stability, tiny soil fungus is usually not the first thing that comes to mind. However, recently, more and more studies show that mycorrhiza is integral to many ecosystems. This particular type of fungus colonizes plant roots and helps increase the host plant's uptake of key resources such as phosphorous. In exchange for this service, the mycorrhiza plays an almost parasitic role take photosynthates such as sugars away from the plants. Many native plants in North America depend on these key symbionts, and on an ecological scale these tiny fungi play a huge factor in things such as plant community assemblage, succession and also plant abundance in a host of environments. However, this particular interaction between mycorrhiza and native plants can be interrupted by the invasion of invasive allelopathic plants.

All plants produce and release secondary chemicals to the surrounding environment. Studies show that by producing allelopathic chemicals, plants can suppress the growth of neighboring plants and gain a competitive advantage. Plants can also create a set of complex secondary chemicals to defend themselves from harmful fungal and viral infections in their native habitats. Although these plants normally produce these chemicals to keep threats and competition at bay, these same chemical compounds can interfere and change biological interactions within communities outside their native system. The secondary chemicals released from these invasives can damage soil organisms such as the mycorrhiza that native plants need. Inadvertently, the invasive plant uses these released allelopathic chemicals as "novel weapons" against mycorrhiza and have been shown to prevent germination, colonization of mycorrhiza on native plants or even destroy the soil communities themselves. Despite this important interaction, there is very little understanding on how such allelopathic invasive plants affect the mycorrhiza community over an extended period of time.

My study focuses on the long term effect of the allelopathic invasive plant, Garlic Mustard (Alliaria petiolata) on the mycorrhizal community. In this project, four different sites with varying ages of Garlic Mustard were chosen, ranging from uninvaded to presence of garlic mustard for over 20 years. I quantified each site's mycorrhiza abundance by growing corn in the soil from each site. I found that significantly higher densities of mycorrhiza in corn grown in soil from the uninvaded site. Further, when I experimentally added garlic mustard plants to the soil, this resulted in a decrease in mycorrhiza abundance in corn grown in soil from the uninvaded and recently invaded sites, but not in the sites with a longer history of garlic mustard presence. Thus, this particular type of below ground fungus community may be either evolving in response to Garlic Mustard, or Garlic Mustard is destroying certain species of mycorrhiza in the fungal community.