Effects of chaining and burning in Acacia ramulosa shrublands of the Peron Peninsula, Shark Bay, Western Australia

Abstract

We tested the effect of chained and burnt buffers installed across the Peron Peninsula at Shark Bay, Western Australia, in 1995 on the plant communities. Chaining modified fuel by flattening shrubs to provide a more continuous fuel bed by adding vertically arranged shrub fuel to the in situ sparse ground fuels. Twenty-six, 10 × 10-m permanent plots were established in the treated buffers and adjacent untreated shrubland. Plots were evaluated in 1996, 2001 and 2008. By 1996, fire and chaining had promoted a suite of species that included 29 not observed in adjacent untreated shrubland. High rainfall before the 2001 assessment produced an increase in species richness in both burnt and unburnt treatments. By 2008, 20 of the 29 fire-promoted species were found in the untreated area after rainfall leaving nine species uniquely responsive to the fire and chaining treatment. The Acacia ramulosa W.Fitzg. sandplain communities in our study area appear to be sustained by high rainfall years promoting regeneration of 84% of species with a smaller proportion (16%) regenerated only in burnt areas. The dominance of periodic rainfall in promoting regeneration led to the likely reduced effectiveness of the fire buffers in preventing the spread of fire. There is the potential for extensive fires in this landscape following favourable rainfall.