Germination response of grassland species to plant-derived smoke

In fire-prone ecosystems, many species require signals such as heat or smoke to cue seedling establishment to the relatively favorable post fire environment. Grassland ecosystems are often maintained by recurring fire and many grassland species are considered well adapted to fire. Despite this, smoke-induced germination has been studied much less in grasslands than in shrublands subject to crown fire. We tested 15 species native to the southern Great Plains and Edwards Plateau of Texas for smoked-stimulated or heat stimulated germination. Smoke and heat treatments were followed by either a true wet stratification or a dry cold period. Four species exhibited smoke-stimulated germination while the others exhibited no response or were inhibited by smoke. In two of the species that showed a positive response, smoke acted as a substitute for wet cold stratification. Heat treatments proved lethal to all species tested. (C) 2011 Elsevier Ltd. All rights reserved.