Elsevier

Forest Ecology and Management

Volume 363, 1 March 2016, Pages 130-139
Forest Ecology and Management

Effects of the fire regime on mammal occurrence after wildfire: Site effects vs landscape context in fire-prone forests

https://doi.org/10.1016/j.foreco.2015.12.008Get rights and content

Highlights

  • We examined effects of the fire regime on mammals at the site and landscape scale.

  • Spatial variation in fire severity influenced post-fire occurrence of mammal species.

  • Environmental conditions influence post-fire recovery of habitat for mammals.

  • The effects of fire regimes need to be considered at multiple spatial scales.

Abstract

Wildfires have major impacts on ecosystems globally. Fire regimes (including fire frequency, intensity, season and type of fire) influence the status of species by altering habitat suitability at the site scale, and by creating heterogeneity at the landscape scale. The relative effects of site and landscape-scale fire attributes on animal species are rarely examined together. Such knowledge is important, given that fire regimes are sensitive to changing land management practices; and that fires are predicted to become larger and more frequent in some regions as a result of climate change. Here, we tested the relative influence of elements of the fire regime (fire severity, fire history) at the site-scale, and the landscape context (extent of surrounding unburnt forest, fire heterogeneity) on the occurrence of native terrestrial mammals after severe wildfire in south-eastern Australia. We conducted surveys by using automatically triggered, infrared cameras at 80 sites in fire-prone eucalypt forests, 2–3 years post-wildfire. Thirteen native mammal species were recorded, eight of which were detected with sufficient frequency for analysis. Most species were widespread (35–90% of sites) and recorded in all fire severity classes. Fire effects at the site-level were more influential than landscape context effects arising from heterogeneity in the fire regime (e.g. extent of surrounding unburnt forest). Fire severity was the most influential of the fire-regime elements investigated, but it affected different species in different ways. This study highlights three main points relevant to conservation of terrestrial mammals after wildfire. First, spatial variation in fire severity associated with wildfire (ranging from unburned to severely burned stands) is an important contributor to the post-fire status of species. Second, post-fire environmental conditions are significant: here, rapid regeneration of vegetation following drought-breaking rains greatly influenced the suitability of post-fire habitats. Third, it is valuable to consider the effects of the fire regime at multiple scales, including both the site (forest stand) and its landscape context. Insights from short-term surveys, such as this, will be enhanced by complementary longitudinal studies, especially where they encompass environmental variation through the post-fire succession.

Introduction

Fire has an important role in determining the distribution and abundance of species in fire-prone regions globally (Bond et al., 2005, Bowman et al., 2013). Multiple components of the fire regime (sensu Gill, 1975), including fire frequency, intensity, season and type of fire, can influence biodiversity (Gill, 1975, Gill and Allan, 2008). The intensity of a large wildfire, for example, influences the composition and spatial pattern of plant communities (Pausas et al., 2008, Roman-Cuesta et al., 2009, Turner et al., 1994). While knowledge of the relationship between fire regimes and plant communities is growing (Driscoll et al., 2010, Whelan et al., 2002), much less is known about the components of the fire regime and their influence on fauna and ecosystems (Clarke, 2008, Fontaine and Kennedy, 2012). Fire regimes are expected to change in future decades as a consequence of climate change (Krawchuk et al., 2009, Moritz et al., 2012); wildfires are predicted to increase in size, occurrence and frequency over a longer fire season in some fire-prone areas (Clarke et al., 2011, McKenzie et al., 2004, Wotton et al., 2010). Fire regimes are also altered by changes in land management practices, including the use of planned burning for ecological or fuel reduction purposes (Moritz et al., 2012, Parks et al., 2015).

The fire regime can influence the occurrence of animal species at two spatial scales: (a) at the site-level via its influence on the suitability of habitat at a particular location; and (b) at the landscape-level via its influence on the landscape context of a site. At the site-level, fire intensity and the time between fires are important components of the fire regime. Fire intensity relates to the amount of energy emitted during the fire, whilst fire severity relates to the amount of vegetation or organic matter lost after a fire event (Keeley, 2009). Here, we refer to fire severity. A high severity fire may result in complete incineration of ground and canopy vegetation; whereas in a low severity fire the understorey may burn in a patchy manner and the canopy remains largely unburnt. Consequently, fire severity will have marked effects on the availability of resources such as shelter, foraging substrates and food for animal species post-fire (Fontaine et al., 2009, Keith et al., 2002, Smucker et al., 2005). The effect of fire severity on fauna after wildfire has rarely been quantified (but see Lindenmayer et al., 2013). Fire history (including the time between fire events), can also influence the suitability of a site by affecting vegetation successional stage and associated habitat structure (Bradstock et al., 2005). Sequential fires at short or longer intervals can have differing outcomes for structural features that provide habitat resources for animal species (Haslem et al., 2011). For instance, in semi-arid mallee vegetation in Australia, long fire intervals (at least >40 years) are required for tree hollows to develop and be suitable for hollow-nesting animals, whereas leaf litter can accumulate quickly within shorter fire intervals to provide habitat for other species (Haslem et al., 2011).

At the landscape-level, spatial variation in components of the fire regime contribute to landscape heterogeneity. Large fires vary spatially in their intensity, leading to a post-fire landscape of vegetation patches of differing fire severity (Leonard et al., 2014, Roman-Cuesta et al., 2009, Schoennagel et al., 2008). Animal populations potentially are influenced by the way in which such fire-induced heterogeneity determines the landscape context at a particular site. For instance, a patchy mosaic of burnt and unburnt vegetation may benefit species that move between fire age-classes to obtain different resources (e.g. shelter, food) (Buchalski et al., 2013, Doumas and Koprowski, 2013b). Unburnt patches within the landscape may act as refuges for species which otherwise are eliminated from, or are scarce in, severely burnt areas (Robinson et al., 2013). The extent and proximity of refuges may influence the rate of population recovery at severely burned sites (Bradstock et al., 2005, Robinson et al., 2013).

Environmental attributes, such as topographic variation in soils and moisture, also influence landscape heterogeneity and may mitigate the effects of fire by enabling survival of animals during or after a fire event (Bradstock et al., 2010, Garvey et al., 2010, Leonard et al., 2014). Understanding the effects of the fire regime and environmental attributes on mammal species at multiple scales can improve ecological knowledge of species responses, and is valuable for applied management.

Here, we examine the effects of an extensive wildfire on the occurrence of native terrestrial mammals in foothill eucalypt forests of south-eastern Australia. These are some of the most fire-prone forests worldwide (Adams and Attiwill, 2011). We surveyed the mammal assemblage 2–3 years after wildfire, at sites stratified in relation to two components of the fire regime, fire severity and fire history (interval since last fire). The overall aim was to test the relative influence on native mammals of components of the fire regime operating: (a) at the site-level (i.e. site specific wildfire severity and fire history); and (b) at the landscape-level (i.e. amount of unburnt forest and heterogeneity of fire severity within the surrounding landscape). We predicted that site level effects, particularly wildfire severity, would be the primary influence on the distribution of mammal species; but that landscape context would also influence the occurrence of species, in particular via unburnt forest functioning as a refuge and providing a source of colonising individuals for nearby burnt sites.

Section snippets

Study area

The study was based in the foothills of the central highlands of Victoria, Australia (Fig. 1), where elevation ranges from ∼150 to 1000 m. The climate is temperate with cool winters (mean monthly minimum 4 °C) and mild summers (mean monthly maximum 23 °C), and a mean annual rainfall of ∼1200 mm (BOM, 2013). From 1997 to 2009, a severe drought occurred in south-eastern Australia (van Dijk et al., 2013). The drought broke in 2010, with above-average annual rainfall recorded in both 2010 and 2011 (

Species recorded and detection probability

From January–August 2011 we surveyed a total of 6084 camera trap-nights. From this effort, 13 species of native mammals were detected, eight of these were examined further (Table 2). Five species (mostly arboreal) were detected at fewer than seven sites (<9%) and were excluded from analyses. These included the common brushtail possum (Trichosurus vulpecula) recorded at 6 sites (8%), the koala (Phascolarctos cinereus) detected at 2 sites (3%), whilst the remaining three species were rare and

Discussion

Understanding how fire regimes influence fauna at different scales can improve ecological knowledge for fire management (Driscoll et al., 2010, Di Stefano et al., 2011). In the aftermath of a severe wildfire, we had a unique opportunity to investigate how native terrestrial mammals were influenced by fire-regime components at multiple scales, in one of the most fire-prone forests in the world. At 2–3 years post-fire, fire effects at the site-level exerted more influence on the occurrence of

Acknowledgements

This study is part of the Faunal Fire Refuges Project, funded by the Department of Environment, Land, Water and Planning (DEWLP), Victoria. We thank DELWP, Parks Victoria, Victorian State Forests, and associated staff. Natasha Robinson provided valuable contributions to the overall project design and site selection. We appreciate the help of numerous staff and volunteers for field assistance; and Dale Nimmo for advice on statistical models. Comments from Dan Lunney improved the final version of

References (73)

  • S.C. Banks et al.

    Starting points for small mammal population recovery after wildfire: recolonisation or residual populations?

    Oikos

    (2011)
  • Bartoń, K., 2014. MuMIn: multi-model inference. R package, version...
  • Bates, D., Maechler, M., Bolker, B., Walker, S., 2014. lme4: linear mixed-effects models using Eigen and S4. R package...
  • W.J. Bond et al.

    The global distribution of ecosystems in a world without fire

    New Phytol.

    (2005)
  • D.M. Bowman et al.

    Pyrogeography and the global quest for sustainable fire management

    Ann. Rev. Environ. Resour.

    (2013)
  • R.A. Bradstock et al.

    Which mosaic? A landscape ecological approach for evaluating interactions between fire regimes, habitat and animals

    Wildlife Res.

    (2005)
  • R.A. Bradstock et al.

    Effects of weather, fuel and terrain on fire severity in topographically diverse landscapes of south-eastern Australia

    Landscape Ecol.

    (2010)
  • M.R. Buchalski et al.

    Bat response to differing fire severity in mixed-conifer forest California, USA

    Plos One

    (2013)
  • K. Burnham et al.

    AIC model selection and multimodel inference in behavioral ecology: some background, observations, and comparisons

    Behav. Ecol. Sociobiol.

    (2011)
  • Canty, A., Ripley, B., 2014. Boot: Bootstrap R (S-Plus) Functions. R package version...
  • P.C. Catling et al.

    The distribution and abundance of ground-dwelling mammals in relation to time since wildfire and vegetation structure in south-eastern Australia

    Wildlife Res.

    (2001)
  • L.K. Chambers et al.

    Habitat selection of the long-nosed bandicoot, Perameles nasuta (Mammalia, Peramelidae), in a patchy urban environment

    Austral Ecol.

    (2002)
  • E.K. Chia et al.

    Fire severity and fire-induced landscape heterogeneity affect arboreal mammals in fire-prone forests

    Ecosphere

    (2015)
  • R.K. Chowdhury et al.

    Understanding South Australian rainfall trends and step changes

    Int. J. Climatol.

    (2015)
  • M.F. Clarke

    Catering for the needs of fauna in fire management: science or just wishful thinking?

    Wildlife Res.

    (2008)
  • H.G. Clarke et al.

    Regional signatures of future fire weather over eastern Australia from global climate models

    Int. J. Wildland Fire

    (2011)
  • N. De Bondi et al.

    A comparison of the effectiveness of camera trapping and live trapping for sampling terrestrial small-mammal communities

    Wildlife Res.

    (2010)
  • J. Di Stefano et al.

    Fire, landscape change and models of small mammal habitat suitability at multiple spatial scales

    Austral Ecol.

    (2011)
  • S.L. Doumas et al.

    Effect of heterogeneity in burn severity on Mexican fox squirrels following the return of fire

    Int. J. Wildland Fire

    (2013)
  • S.L. Doumas et al.

    Return of fire as a restoration tool: long-term effects of burn severity on habitat use by mexican fox squirrels

    Restor. Ecol.

    (2013)
  • Fiske, I., Chandler, R., Miller, D., Royle, A., Kery, M., 2013. Unmarked. R...
  • J.B. Fontaine et al.

    Meta-analysis of avian and small-mammal response to fire severity and fire surrogate treatments in U.S. fire-prone forests

    Ecol. Appl.

    (2012)
  • B.J. Fox

    Fire and mammalian secondary succession in an Australian coastal heath

    Ecology

    (1982)
  • N. Garvey et al.

    Survival behaviour of swamp wallabies during prescribed burning and wildfire

    Wildlife Res.

    (2010)
  • A.M. Gill

    Fire and the Australian flora: a review

    Aust. Forest.

    (1975)
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    Present address: Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Victoria 3086, Australia.

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