Invasive plant species are currently a threat to native species and communities,
and two major challenges facing scientists today are trying to figure out how to deal with the invasive plants and trying to pinpoint their effects on the native communities. While some methods of removal have been effective, it is still unclear how the invasive plants affect the natives. Two species of the shrub buckthorn are invasive in the United States and both are causing problems in the state of Maine. I studied the native plants in areas with and without buckthorn to determine the effects of buckthorn on native plants. The sites without buckthorn served as models of what the natural environment should look like and were compared to the sites influenced by buckthorn to determine if buckthorn affected the structure of the community. To establish the structure of the communities I measured the functional traits of the native plants. The distributions of plant height, chlorophyll, and SLA values all shifted in response to buckthorn, resulting in plants that were taller and had thinner leaves with less chlorophyll. I also assessed changed in species richness and evenness. This study showed that the presence of buckthorn resulted in a change in the community. Invasive plant species are changing the way natural communities look by altering the size and shape of the available trait space, which could lead to exclusion of non-adaptive species or lead to growth constraints.
Perry, Alexandra, "Effects of Buckthorn (Rhamnus Cathartica and Rhamnus Frangula) on Native Flora Functional Traits" (2015). Honors College. 215.