El fuego favorece la invasión de Teline monspessulana (Fabaceae) al aumentar su germinación

Abstract

Worldwide, it has been reported that invasive species and fire can interact positively changing landscape dynamics and ecosystem cycles. This work aims to study the effect of forest fires on the seed bank of Teline monspessulana (L.) K. Koch (French Broom) and its implications for the invasion of the species in the mediterranean area of south- central Chile. For this aim, soil seedbank samples were subjected to different treatments that simulate fire conditions through controlled burns. In addition, for seeds taken from mature plants the optimal range of temperatures at which germination occurs was determined. The results show that after a wildfire germination of T. monspessulana increases significantly. Heating of the seeds was the factor that triggers this increase in germination. Furthermore, it was determined that the seeds reach their maximum germination rate when preheated between 80 and 120 oC for 10 minutes. At 140 oC, 100 % of the seeds die. During a fire, optimal temperatures for germination are reached about 2 cm in depth within the soil or at the surface in areas where the accumulation of fuel (biomass) does not exceed 5 tons ha -1 . The small portion of the seed bank that manages to be stimulated is offset by the large seedbank that can exceed 8000 seeds m -2 . This study shows that the fire, a common phenomenon in mediterranean areas and increasingly frequent in central Chile, would be promoting the persistence of T. monspessulana in areas with high human disturbance.