Establishment of honey locust (Gleditsia triacanthos) in burned Pampean grasslands

The effect of a single fire event on the subsequent invasion dynamics of honey locust was studied in old-field and relict tussock grasslands of the Inland Pampa, Buenos Aires, Argentina. We added tree seeds to control (nonburned) and burned plots and monitored the recruitment and individual growth of three plant cohorts during 1999 to 2003. Burning increased seedling emergence during wet years, especially in tussock grassland. However, growth of establishing trees was significantly reduced in burned grassland plots. Without prior burning, tree growth was most strongly suppressed by the native tussock grass community. Thus, honey locust invasion into burned grasslands was a context-dependent process, which varied in response to interannual climate fluctuation and resident community structure.