Smoke and Ash Effects on Seedling Emergence from Germinable Soil Seed Bank in Fescue Prairie

Seedling recruitment plays a crucial role in recovering plant communities after disturbance. As a natural disturbance, fire can mediate species composition in fescue prairie. However, little was known about the effects of important fire cues on seedling recruitment in fescue prairie. Soil seed bank samples were taken from the top 5 cm of the soil profile and separated into litter, 0- to 1-cm, and 1- to 5-cm layers. Seedlings emerging from soil seed banks incubated in the greenhouse were examined after applying smoke, ash, and smoke plus ash in 2013 and 2014, to assess their effects on the density, richness, and composition of seedlings emerging from the soil seed bank in fescue prairie. Smoke plus ash significantly increased the number of Artemisia ludoviciana Nutt. seedlings emerging from 0- to 1-cm soil layer and Conyza canadensis (L.) Cronquist seedlings emerging from the litter layer (P < 0.05), while ash significantly increased the number of Artemisia frigida Willd. seedlings emerging from 0- to 1-cm soil layer (P < 0.05). Densities of total seedlings emerging from the 0- to 1-cm soil layer were increased by smoke plus ash in 2013 and by ash in 2014 (P < 0.05). Smoke plus ash and ash alone had more prominent effects on seedling density and richness of native forbs. Species composition was altered by ash in the 0- to 1-cm, 0- to 5-cm, and all layers combined in 2013 (P < 0.05). Direct fire cues appear to stimulate recruitment of some species, especially native forbs, contributing to potential changes in species composition of fescue prairie.