Megan Killian - Plant Ecology Lab
Towson University, MD
A Comparative Study of Fruit Predation and Demography Between Two Rubus Species: Rubus phoenicolasius (Invasive Wineberry) and Rubus argutus (Native Blackberry)
Invasive species are known to completely replace existing native vegetation and have a strong impact on the economy, the health of the environment, and human health. A comparative study of an invasive and native species is necessary in order to determine why the invasive flourishes in a habitat and this information is then used to prevent future invasions. I focused on the reproduction of two Rubus species: Rubus phoenicolasius (invasive wineberry) and Rubus argutus (native blackberry); both species reproduce sexually (seeds) and asexually (cloning). Fruit predation is beneficial because seeds that pass through the gut have an increased germination potential. Greater fruit predation on invasive wineberry may be a reason why it is more successful because multiple seeds would be dispersed throughout an area. To compare rates of fruit removal by "predators" (seed dispersers) between wineberry and blackberry I monitored the development of fruit on plants. Wineberry had a higher rate of fruit predation and blackberry had a higher fruit death rate, these data suggest increased seed dispersal for invasive wineberry, which may support increased fitness. An increased frequency of clonal reproduction for invasive wineberry may be an additional factor that allows it to succeed in a habitat because the plant is not as dependent on seed dispersal if reproduction is clonal. To compare frequency of clonal rhizomes vs. perennial rootstocks between wineberry and blackberry I sampled individuals along a transect that cut through the entire patch. Although clonality does exist in both species, I had low observance of clonal propagation. However, an increased number of canes per rootstock for the invasive wineberry may be beneficial. Even though an invasive and native species may seem very similar the invasive does posses certain characteristics that allow it to succeed in a habitat.
After completion of my undergraduate at Towson University I plan on freaking out. Just kidding, I plan on going to graduate school.
Funding provided by National Science Foundation-REU