Preburn History and Seasonal Burning Effects on the Soil Seed Bank in the Fescue Prairie

• Published in: The American midland naturalist 2011-01, Vol.165 (1), p.74-90
• Main Authors: Romo, J. T, Gross, D. V
• Format: Article
• Language: English
• Subjects: Banks; Development; Flowers & plants; Forbs; Grasses; Growing seasons; Plant communities; Plant succession; Plants; Prairies; Seed banks; Seedlings; Seeds; Soil seed banks; Soil water content; Soils
• ISSN: 0003-0031; 1938-4238
• DOI: 10.1674/0003-0031-165.1.74

Fescue Prairie is one of the most threatened ecosystems in Canada, and burning is essential for conserving remnants of this grassland. Burning is a key process in the natural disturbance regime, but its effect on the soil seed bank in Fescue Prairie is poorly understood. We tested the hypotheses that (1) preburn history influences the density and composition of seedlings emerging from the soil seed bank, and (2) burning in different seasons reduces densities and changes the composition of seedlings emerging from soil seed banks compared with non-burned controls in Fescue Prairie. Seedling emergence from seed banks was studied for 5 y in non-burned controls and following burning before, during or after the growing season on sites with different preburn histories (sites burned two times or sites burned >90 y before this study). Preburn history had no effect (P ≥ 0.14) on the density of native graminoids, native forbs, non-native species, total species richness (R) and diversity (H′) of species emerging. Burning during or after the growing season reduced H′ of emergent seedlings by 13% compared with burning before the growing season (P  =  0.02). Total seedling densities, densities of graminoids and forbs, R and H′ all varied significantly (P ≤ 0.01) among years. Non-metric multidimensional scaling indicated species composition for seedlings emerging from seed banks correlated with preburn history, years after applying seasonal burning treatments, and soil water content in plant communities but not with season of burning. After burning remnant Fescue Prairies, inter-annual variation in the densities, R and H′ of seedlings emerging from seed banks usually overshadows preburn history and seasonal burning effects on emergent seedlings; however, species composition changes with preburn history, soil water content and years after burning.