Changing fire regimes: The response of litter-dwelling invertebrates to altered seasonality and frequency of fire

Abstract

Mediterranean climate regions are experiencing changes that are projected to have significant impacts on patterns of temperature and rainfall, thereby affecting key ecosystem drivers such as fire regimes. In the sclerophyll-dominated vegetation communities of southern Australia, land managers are responding to increased wildfire probabilities through the use of more frequent low intensity (prescribed) fire. With burning occurring more often throughout the year, plant and animal communities are experiencing altered fire regimes; with changes to both frequency and season of burn. Here I report on the results of a long-term, replicated study, investigating the effects of fire frequency (high vs low) and seasonality (autumn vs spring) on a biodiverse and functionally important component of the fauna (litter-dwelling invertebrates). At the ordinal level, three broad patterns of response were detected: (i) no effect of fire treatment on abundance, (ii) a burning treatment effect, suggesting that fire in any season and at any frequency lowers abundance, and (iii) a significant negative effect of fire frequency on abundance. No season of fire effects were apparent for any group. The mechanisms underpinning these responses warrant further investigation, particularly in light of proposed increases in the amount of prescribed fire to be applied to these forest systems in coming years.