A Life History Analysis of Invasive Behavior in Native and Naturalized Species: Rubus odoratus and Rubus allegheniensis

Abstract

Invasive species are defined broadly as “non-indigenous species or strains that become established in natural plant communities and wild areas and replace native vegetation” (Czarapata, 2005). Based on my own recent research as well as the data reviewed in this paper, I argue that this definition is limiting in the context of climate change and globalization. Human disturbances have already changed ecosystem composition to such an extent that the original location of plant origin, although still extremely important, plays less of a deciding factor in the invasive capacity of the species. The native and naturalized species in this study (Rubus odoratus and Rubus allegheniensis) display many of the same life history characteristics often attributed to non-native species. Research was carried out through two field studies in the University of Michigan’s Nichols Arboretum in Ann Arbor. The study used life history theory as a framework to assess the role environmental factors can play in shaping an organism’s traits. Tradeoffs between seed quantity and seed size, as well as cane growth and fruit production were carefully examined. Lastly, a test was done to replicate the effect of increased atmospheric nitrogen, removing the limiting effect of nitrogen on plant growth. Results from the study reveal that the two species use two different life history strategies that nonetheless provide them with a similar potential for invasive behavior. Understanding the tradeoffs present in these species informs management decisions on how to keep population numbers in check most effectively.