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Atherton, Australia

Williams P.R.,James Cook University | Collins E.M.,Vegetation Management Science | Blackman M.,Friendly Fire Ecological Consultants | Blackman C.,Friendly Fire Ecological Consultants | And 5 more authors.
Australian Journal of Botany | Year: 2014

Introduced grasses, such as buffel, alter the dynamics of grassy ecosystems by replacing native species and influencing recruitment. Several different smoke-derived chemicals are separately responsible for the promotion and inhibition of germination of various plant species. We tested whether smoke derived from the introduced buffel grass (Cenchrus ciliaris) produced the same density of germination as provided by smoke derived from a native spinifex grass (Triodia brizoides). Smoke from both spinifex and buffel grass significantly enhanced the germination of a native lemon grass (Cymbopogon obtectus) in comparison to untreated seed, reflecting the significant role of fire in woodlands across northern Australia. This is the first record of smoke-promoted germination in a species of Cymbopogon. However, smoke from the exotic buffel grass provided the same level of germination as that from the native spinifex, suggesting similarity in smoke chemicals involved. Further research is required to test the effect of buffel smoke on the germination of other species and whether exotics such as buffel grass provide the same temperature profile in the topsoil as does spinifex, and therefore equivalent germination cues to heat-shock responsive native plants. © 2014 CSIRO. Source


Williams P.R.,James Cook University | Collins E.M.,Vegetation Management Science | Blackman M.,Friendly Fire Ecological Consultants | Blackman C.,Friendly Fire Ecological Consultants | And 7 more authors.
International Journal of Wildland Fire | Year: 2015

Unplanned, unmanaged wildfires are a significant threat to people, infrastructure and ecosystems around the world. Managed, planned burning is widely used for reducing the incidence, extent or intensity of wildfires. Fire weather and the season of burning are recognised as crucial factors influencing fire behaviour but the demonstrated influence of ignition technique on fire behaviour is not as prominently discussed in relation to planned fires. We found wildfires, irrespective of season, burnt the ground layer more completely (i.e. were less patchy) and produced greater crown scorch severity than did planned fires in a spinifex (Triodia spp.)-dominated open woodland. Fires ignited with a 50-m line burning with the wind produced significantly higher intensities than did line ignition against the wind, and spot ignitions with or against the wind. These data suggest that the higher severity of wildfires in spinifex-dominated habitats is strongly influenced by long fire fronts, in addition to fire season and weather conditions. This study supports the value of planned burning for reducing fire severity and highlights the value of spot ignitions in ecological burning to create a patchily burnt landscape, with limited canopy severity. Source

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