Fire Regimes and Invasive Species: A Changing Landscape

Abstract

Tropical and semi-arid savannas are extremely fire prone (Lawes, 2011) with dry season fires being a feature of this landscape in Australia. Historically fire has been an integral part of shaping the landscape into its present state. Initially occurring naturally due to dry lightning strikes, followed by Aboriginal fire stick agricultural practices (Pausas and Keeley. 2009), which has had a substantial impact on the landscape. With the arrival of the Europeans from the late 18th century onwards fires were perceived negatively, which resulted in there prevention and exclusion from the Australian landscape (Baker et al 2015; Beringer et al, 2015). This resulted in the increase of fuels and a change in fire regimes, with larger, higher intensity uncontrollable wildfires to occur, which had a negative impact on native vegetation (Jurskis and Underwood, 2013). Today fire is seen as an important and integral part of the natural ecosystem of tropical and semi-arid savannas and is used as a land management tool where possible (Walsh et al, 2014). However pastoralists involved in the cattle industry require improved pastures through introduced grasses and this has resulted in a number of exotic grasses invading native tropical and semi-arid ecosystems (Driscoll et al, 2014). This invasion has altered fire regimes dynamics through higher fuel loads, resulting in higher intensity, more severe fires and a change in vegetation response to fire (Setterfield et al, 2013).