Less fuel for the fire: malleefowl (Leipoa ocellata) nesting activity affects fuel loads and fire behaviour

Abstract

Context Fire is an important driver of species distributions globally. At the same time, biota also influence fire regimes. Animal activities that modify fuel characteristics may influence fire regimes and hence ecosystem function. However, apart from herbivory, animal effects on fuels and fire behaviour have rarely been studied. Aims We examined the effect of nest building by malleefowl (Leipoa ocellata) on litter fuel loads and fire behaviour in the fire-prone, semiarid mallee ecosystem of south-eastern Australia. Malleefowl nests consist of mounds constructed by raking large amounts of leaf litter from the surrounding area. Mound-building activity is likely to affect fuel loads and potentially affect fire behaviour in this environment. Methods Litter cover and mass were compared between paired mound and non-mound sites. Fire behaviour modelling was used to determine whether differences in fuel load were likely to translate into differences in fire behaviour. Additionally, in an area recently burnt by wildfire, the minimum diameter of burnt stems was compared between mound and non-mound sites to determine the effects of malleefowl activity on fire intensity. Key results Malleefowl nesting activity reduced litter fuel loads around mounds. Fire behaviour modelling and post-fire minimum stem diameter measurements showed this led to reduced fire intensity around mounds, even under extreme fire weather conditions. Conclusions The likelihood and intensity of fire is reduced around active malleefowl mounds. Malleefowl nesting contributes to more heterogeneous burn patterns in mallee vegetation. This in turn may contribute to the formation of fire refuges. Implications Few studies have examined the effects of animal activities on fire. This study demonstrates that non-trophic interactions of fauna with fuels may influence fire regimes. Species that reduce or disrupt the continuity or connectivity of fuels could have similar effects to malleefowl in fire-prone regions. Further examination of the interactions of animals and fire regimes will contribute to a better understanding and conservation management of fire-prone ecosystems.