Managing fire mosaics for mammal conservation

Fire management increasingly is focused on maintaining ‘fire mosaics’ comprising heterogeneous patches of differing fire history. However, almost any fire regime will create a ‘mosaic’. What’s lacking is empirical data that distinguishes the characteristics of mosaics that will enhance the conservation of biodiversity. So, how does the composition of fire histories in the landscape influence species distributions? What other ecological processes are important? And what mosaic characteristics are desirable for biodiversity conservation? In a new study, published in Journal of Applied Ecology, my colleagues and I set out to get some answers.

We conducted a broad-scale natural experiment in semi-arid Australia. Our focus was on a small mammal assemblage including dasyurids, burramyids and murids. We surveyed mammals in landscapes selected to represent a range of fire histories, and therefore different fire mosaic properties. Specifically, we examined the influence of five landscape properties on the distribution of small mammals: the extent of fire age-classes, the diversity of fire age-classes, the composition of vegetation types, rainfall history and biogeographic context.

     Wildfire in semi-arid mallee vegetation (photo by Lauren Brown)

What did we find? We identified the total extent of habitat, particularly that of a suitable seral stage, as a key spatial property of fire mosaics. Areas of older post-fire vegetation provided particularly important habitat for native small mammals. Recent rainfall and biogeographic context were also strong influences on capture rates of small mammals. Interestingly, there was little evidence that the diversity of fire age-classes influenced either individual species or species richness.

What does this mean for ecological management? Sufficient habitat at a suitable seral stage within the landscape is a key requirement for species conservation. In mallee ecosystems, the retention of older vegetation is recommended to create more desirable fire mosaics for native small mammals. In addition to such spatial properties of mosaics that are amenable to manipulation, an understanding of how other ecological processes affect the biota (such as rainfall) is also essential for informed conservation management.

Want to find out more? Email me for a copy of the paper: ltkelly@unimelb.edu.au

Kelly, L.T., Nimmo, D.G., Spence-Bailey, L.M., Taylor, R.S, Watson, S.J. Clarke, M.F.& Bennett, A.F. (2012) Managing fire mosaics for small mammal conservation: a landscape perspective. Journal of Applied Ecology 49, 412-421. Abstract

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