EXOTICS VS. NATIVES: SOIL FEEDBACKS AND COMPETITION IN CALDÉN WOODLAND, CENTRAL ARGENTINA

MARIANA CHIUFFO; ANDREW MACDOUGALL; JOSÉ L. HIERRO

Conferencia; Biolief 2011; 2011

Soil biota has been proposed to have stronger positive effects on the abundance of exotic plant species than on natives in some ecosystems, potentially driving invasion success alone or by interacting with competitive ability. These individual or interactive effects of soil feedbacks, however, have rarely been described for invasion, with competition alone often serving as the de facto explanation for invader success. In this study, we performed a soil feedback experiment with nine exotic and nine native common plant species in the caldén woodland of central Argentina to investigate how the interaction among plants and soil microbes affects the performance of these groups including competitive abilities. We grew exotic and native species alone and in competition with a phytometer, in both conspecific and heterospecific soils. After three months, we determined plant biomass and quantified feedback strength and competition intensity in exotic and native species using several indices. We found soil feedbacks similarly affected exotic and native species. Likewise, competition intensity was similar between exotics and natives, although we found an effect of soil type on competition where heterospecific soil ameliorated the negative impacts of competition. These results suggest that soil feedbacks do not provide exotics an advantage over natives in our study system.