As reported in the last newsletter, Mike Stevens Team Leader Natural Values has used study leave this year to research the effect of the Mt Lubra fire on small mammal populations. Here is the official abstract of his honours thesis. The full paper can be obtained from Mike. It is well worth reading as there are some serious implications about the decisions to be made about future burning regimes.
The Impact of Severe, Landscape-Scale Wildfire on Small Mammals: Grampians National Park Case Study
M. Stevens (Deakin University, Melbourne, Australia; Parks Victoria, Halls Gap, Australia)
Abstract
Small mammals were used to examine the impact of severe landscape-scale wildfire using the post 2006 wildfire landscape of the Grampians National Park, Victoria, Australia as a case study. Long-term research sites were established using a focal patch design in wildfire (burnt) and unburnt areas with 9620 trap nights across thirty-six sampling units. The influence of fire severity, patch size and habitat connectivity with vegetation structure, floristic associations and overall fuel hazard were measured to investigate correlations with small mammals.
Native small mammal species were severely impacted upon, with only some individual species persisting in extremely low densities within the burnt matrix. Native species diversity and abundance was highest in control (unburnt) compared to all other sites except small, unburnt patches in the burnt matrix. A rapid post-fire resurgence of House Mouse (Mus musculus) demonstrated a preference for severely burnt isolated sites and areas with low vegetation cover. Vegetation structure below one metre, increasing overall fuel hazard and floristic components of logs, wiregrass and Hakea spp. correlated as habitat characteristics for small mammals.
Two years post-wildfire, no study site within the burnt perimeter provided superior refuge presenting potential conservation implications for land management practices. A habitat vacancy model is introduced where recolonisation of small mammals during post-wildfire successional phases depends on the lack of metapopulation extinctions. Conflicting anthropogenic and conservation needs when managing for higher overall fuel hazard are discussed due to its contribution to floristic and structural habitat characteristics essential in maintaining a suite of fauna assemblages.