The effect of recent fire history on the abundance and viability of large seeds in the soil of sclerophyll forest in Tasmania, Australia

Abstract

There are few data on the effects of recent fire history on the composition of soil seed banks in sclerophyll forest communities. We predicted that the abundance and viability of soil-stored seeds would vary with fire history. Soils were sampled from areas with six different fire histories on Mt Nelson, Tasmania, Australia. Large seeds were extracted by hand separation and tested for viability. Responses to at least one of the two strongly-correlated components of fire history were detected in several taxa and for native and exotic seed. Native seeds, exotic seeds, Astroloma humifusum seed and Exocarpos cupressiformis seed were all more abundant in the soils of areas with one or less fires in the last 60 years than in the soils of areas burnt five times over the last 60 years. The viability of A. humifusum seeds decreased with fire frequency. These results support the hypothesis that frequent and recent fire can deplete the soil seed bank, and reduce soil seed viability, at least for some large-seeded species and species groups.