The influence of fire regime on legume reproduction and establishment in the longleaf pine-wiregrass ecosystem

Legume species (Fabaceae) are important functional and compositional components of the fire-maintained and species-rich longleaf pine (Pinus palustris)-wiregrass (Aristida stricta) ecosystem of the southeastern United States.  Legumes replenish nitrogen lost from soil due to frequent fire, provide valuable forage for wildlife, and contribute significantly to floristic diversity. The purpose of the study is to determine the influence of managed fire regimes on reproduction and abundance of legumes. Specifically, we examine the effects of season of burn on legume recruitment and survival as well as the effects of season of burn, fuel loading, and fire duration on legume reproduction and seedling recruitment. For this study, the effects of season of burn on annual recruitment and survival of nine legume species in a young longleaf pine plantation have been recorded since 2005. Additionally, garden plot experiments are being used to investigate the effects of fuel loading, fire duration, and season of burn on seed production of Tephrosia virginiana and seedling recruitment of three species of legumes with varying levels of hardseededness. Preliminary results indicate that season of burn may explain patterns of legume establishment and abundance. In addition, data are presented which analyze the fine scale patterns of fire behavior on hardseeded legume germination and reproduction of T. virginiana.