Grasstrees reveal contrasting fire regimes in eucalypt forest before and after European settlement of southwestern Australia

Why the integration of demographic and site-based studies of disturbance is essential for the conservation of jarrah forest fauna

“…Photo Grant Wardell-Johnson. of the jarrah forest over the last 250 years (Ward et al 2001). They also argued that fire incidence on individual grasstrees may represent the fire history of a region, and that their results suggest marked changes in the fire regime of south-western Australia over a short period.…”

“…Wardell-Johnson andHorwitz (1996, 2001) argued that failure to account for subtle differences in vegetation types led to the application of broad-scale regimes of fire, logging and mining that did not reflect previous regimes (for perhaps 40 000-60 000 years) by Aboriginal occupants. There has been much conjecture concerning historical fire regimes in southwestern forested ecosystems (e.g., Hallam 1975, Conacher 1983, Storr 1991, Wardell-Johnson and Horwitz 1996, 2001, Abbott and Burrows 1999, Ward et al 2001, Abbott 2003, Lamont et al 2003. We illustrate this debate by examining the case study provided by Ward et al (2001), and another on the interaction of fire and logging leading to declines in populations of marsupials.…”

“…There has been much conjecture concerning historical fire regimes in southwestern forested ecosystems (e.g., Hallam 1975, Conacher 1983, Storr 1991, Wardell-Johnson and Horwitz 1996, 2001, Abbott and Burrows 1999, Ward et al 2001, Abbott 2003, Lamont et al 2003. We illustrate this debate by examining the case study provided by Ward et al (2001), and another on the interaction of fire and logging leading to declines in populations of marsupials.…”

“…Ward et al (2001) provided an innovative and effective method for ageing Preiss's Grasstree Xanthorrhoea preissii, and determining its fire history over the last 250 years. They found that fires were recorded on grasstrees at 3-5 year intervals prior to 1870, while contemporary recorded intervals are 10-20 years.…”

“…Replication and the recording of site data would allow comparison between community types or vegetation complexes. As Ward et al (2001) did not provide information on the community types, vegetation complexes or defined ecosystems from where they collected their data; it is difficult to check whether their data are relevant to the south-west as a whole. By not doing so, they implied that their data represent the range of environments in which fire occurs within the south-west.…”