Post-burn recovery in the flooding Pampa: Impact of an invasive legume

Abstract

Winter burning of Paspalum quadrifarium Lam. stands ("pajonales") promotes colonization of denuded spaces by several alien species. Lotus tenuis Waldst et Kit. ("lotus"), a recent invader of the region, is able to reach very high densities between the resprouting bunches of the dominant species. Results of a removal experiment performed to evaluate the impact of natural establishment of lotus on post-born colonization of pajonal stands are reported. Seedlings of lotus were removed shortly after their emergence between burned bunches of P. quadrifarium. Eighty days after burning, approximately 30% of the soil surface remained uncovered within removal plots, whereas canopy cover was complete within controls. Furthermore, final (137 days post-burn) total aboveground biomass was 2.7 times higher in control than in removal plots. Removal of lotus significantly (p