Recovering Murray-Malee Shrublands after Fire

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This week’s featured research article has just been published in Austral Ecology and looks at the structural recovery of semi-arid, eucalypt-dominated Murray-Mallee shrublands after fire, and questions whether recovery is affected by spatial variation in climate. The study was undertaken in the Murray-Mallee, a region of approximately 104 000 km2 at the junction of the states of Victoria, South Australia, and New South Wales, south-eastern Australia. The researchers assessed the structure and dynamics of a hummock grass, Triodia scariosa, and mallee eucalypts – two key structural components of mallee shrublands – using a >100 year time-since-fire chronosequence. The relative influence of climatic variables, both individually and combined with time-since-fire, was modelled to account for spatial variation in the recovery of vegetation structural components. Time-since-fire was the primary determinant of the structural recovery of T. scariosa and eucalypts. However, climate, notably mean annual rainfall and rainfall variability, also influenced the recovery of the eucalypt overstorey, T. scariosa cover and mean hummock height. The researchers found that time-since-fire was the key determinant of the structural recovery of eucalypt-dominated mallee shrublands, but there is geographical variation in recovery related to rainfall and its variability. They conclude that this study has at least two important implications. Firstly, changes in the fire regime are likely to have an impact on the structure of mallee shrublands and their value for faunal habitat, carbon storage and biodiversity, which will vary spatially. Secondly, spatial variation in post-fire recovery associated with climate variables (primarily rainfall) means that management prescriptions and actions will need to take into account such variability. That is, management prescriptions and actions cannot be a ‘one prescription fits all’ scenario; different prescriptions and actions will be required for different areas within the broader mallee zone. The paper can be downloaded here (or email jennie.fluin@sa.gov.au for a copy).