Testing the effects of a century of fires: Requirements for post-fire succession predict the distribution of threatened bird species

Abstract

Aim: Managing fire is critical for the conservation of biodiversity in many ecosystems globally. To manage fire effectively, it is necessary to identify the temporal and spatial scales at which it affects a diverse range of species. This information is challenging to obtain for rare and threatened species for which data often are sparse, and in systems with long fire-return intervals (e.g. >100 years). We tested the effects of a century of fires on the distribution of 12 threatened bird species across a 100,000 km2 region in which “long-unburnt” vegetation has been identified as important for the diversity of common species. Location: Semi-arid mallee woodlands of south-eastern Australia. Methods: We developed spatially explicit models to identify the effects of fire history and climatic factors on the distribution of 12 threatened bird species, including two globally endangered species, the Mallee Emu-wren (Stipiturus mallee) and Black-eared Miner (Manorina melanotis). Results: Fire was a driver of distribution for all species. Four species were common in younger vegetation (<20 years post-fire) and 11 were most common in mid (20–60 years post-fire) to older (>60 years post-fire) vegetation. Species’ distributions were further restricted to areas associated with particular vegetation types and climatic conditions. Main conclusions: Comprehensive investigation of the response to fire by a range of threatened species highlights the importance of what is now recognized as mid-successional mallee vegetation (20–60 years post-fire), and that species’ preferences for previously identified “long-unburnt” vegetation extend to ≥60 years post-fire. Fire management conducted with incomplete knowledge, or which is focussed on introducing prescribed burns or suppressing fires for early/late-successional species alone, is unlikely to maximize biodiversity. Effective fire management for biodiversity requires the promotion of ecological processes that result in key successional stages at particular locations in the landscape.