Effects of high temperatures in the germination and seed survival of the invasive species Pinus contorta and two native species of South Chile

Abstract

Studies in South America have reported increments of invasivity of Pinus spp. after fire events. These increments are due to morphological and physiological adaptations to wildfires that some species of this specific genus presents. Pinus contorta is an invasive species in temperate ecosystems, affecting Araucaria araucana and Nothofagus antarctica forests in Malalcahuello National Reserve, Chile. In order to comprehend the regeneration response to post-fire, it is necessary to know the response and tolerance of the seeds to high temperatures. Seeds of P. contorta, A. araucana and N. antarctica were sown in pots with sand and subsequently heated at 80, 100 and 120 °C for five minutes. Germination and seedling survival tests were carried out in a greenhouse. Germination in N. antarctica was null. Heat treatments did not have a negative effect on the germination of P. contorta, but they did on A. araucana inhibiting the germination at temperatures over 100 °C. These results suggest that when undergoing a fire of high intensity, P. contorta has a competitive advantage over A. araucana and N. antarctica; the seed bank would have more possibilities to survive the effects of a wildfire.