Understanding how biological invasions alter community assemblages would improve our ability to restore biodiversity and ecosystem services lost in impacted landscapes. A recent hypothesis, “the evolutionary experience concept”, may provide a theoretical framework at predicting invasion success. The framework proposes that invasion success of an invader can be predicted based on its familiarity to its introduced range as well as how familiar native species are to the traits possessed by the invader (“high” for familiar, “low” for naïve). We seek to provide an empirical test for the evolutionary experience concept, using interactions between non-native plants and native arthropods as models for three invasion scenarios. In a “high-low” scenario, we expect arthropods to decrease in both richness and abundance due to a lack of coevolution between the herbivore and the novel host. In a “low-high” scenario, we expect herbivores to increase in both richness and abundance due to an abundant and susceptible food source. Finally, in a “high-high” scenario, we expect not significant change to richness or abundance compared to native plant-arthropod interactions. We selected a suite of non-native, aggressive plant species in the Mid-Atlantic to test our scenarios, and compared arthropod communities between native and non-native vegetation.
Results/Conclusions
We collected 87,000 individual arthropods, representing over 1,200 unique taxa from 9 non-native plant-native arthropod interactions. Although the difference varied significantly among interactions, in general, we observed fewer species of plant-feeding arthropod and decreased densities of arthropods in invaded landscapes compared to native landscapes, under the “high-low” scenario. In contrast, we observed fewer species, but comparative densities of herbivores in invaded landscapes under the “low-high scenario”. A large proportion (<30%) of herbivores collected in these communities were non-native, and their native distribution may overlap with the distributions of non-native host plants. Differences in abundance for arthropods in the “high-high” scenario were variable, but in general, we observed fewer species of herbivores, and fewer specialist herbivores than expected. Using the evolutionary experience concept, we believe there is evidence to support its merits where invasive plants are novel to native species, but additional studies are necessary to provide support for other invasion scenarios. In addition, nonnative arthropods may mask the efficacy of the predictive model, requiring studies to focus on finer taxonomic resolutions to obtain a stronger signal of change in community structure. We are testing the evolutionary experience concept on other arthropod functional groups (detritivores, predators) in a concurrent study.