Contemporary fire regimes in a fragmented and an unfragmented landscape: implications for vegetation structure and persistence of the fire-sensitive malleefowl

Abstract

Habitat fragmentation alters fire regimes by changing the spatial and temporal context in which fire operates, potentially altering ecosystem state and threatening taxa. In the fragmented wheatbelt of Western Australia, spatial patterns of contemporary fire and their effects on biodiversity conservation are poorly understood. We addressed this by: (1) determining if fire regimes differed between vegetation remnants of differing sizes and uncleared vegetation, using analysis of satellite imagery; (2) determining vegetation structural responses to time since fire in three habitats: mallee-shrub, Acacia shrublands and mallee-heath; and (3) exploring the consequences of these differences, using the fire-sensitive malleefowl (Leipoa ocellata) as a case study. Fire was infrequent in small remnants, more frequent in large remnants, and most frequent in uncleared areas. Key vegetation structural attributes for malleefowl, such as canopy and litter cover, increased beyond 45 years post-fire in mallee-shrub, reached a plateau in mallee-heath after 30–40 years, and declined in Acacia shrublands after 25–40 years. Senescence in long-unburnt vegetation, combined with rare contemporary fires, suggest progressive decline in habitat quality of Acacia shrublands for malleefowl in the wheatbelt. In the adjacent, continuously vegetated landscapes, more frequent (and extensive) fires in structurally developing mallee-shrub communities are of concern for malleefowl conservation.