Shifting fire season: who has it worse resprouters, or obligate seeders?

Abstract

Fire is a major factor shaping plant communities, and plant species have evolved to persist through a fire regime, broadly characterised by the frequency, intensity, and season of burns typical of their region. However, historical fire regimes are shifting with changing climate and other factors, including increased ignition sources, and implemented fires, producing more frequent burns of varying intensity. As such, seasonality of fire is shifting and despite the effects of fire on plant persistence being well studied, there is still little understanding on the effects of fire season. In this study, we set up two sites with five treatment areas, an early autumn burn, late autumn burn, early spring burn, late spring burn and a control. We surveyed multiple shrub species for impacts of seasonal burns on resprouting vigour and post-fire flowering in the mediterranean region of South Australia. Fire severity was also measured using soil temperatures, canopy cover consumption and minimum twig diameter. We found that fire response to fire season varied between trait type included seed storage type and seed dormancy type. This study highlights the impact of season of fire and that it should be considered when making species management decisions for plant species persistence.