> The vast majority of Australia's bush is adapted to regular fire regimes -
especially Eucalyptus forests, inland mallee and grassland.
The following review paper written by eminent biologists from the University
of WA and Kings Park & Botanic Garden in Perth provides the contrary view
for native vegetation that occurs in south-western and south-eastern
Australia:
Bradshaw, SD, Dixon, KW, Hopper, SD, Lambers, H., & Turner, SR (2011).
Little evidence for fire-adapted plant trails in Mediterranean climate
regions. Trends in Plant Science 16: 69-76
The paper was written out of the authors' concerns of the ecological impacts
of the extensive control-burning that occurs in south-western Australia,
similar to those concerns already expressed by Frank O'Connor here on
Birding-aus.
Abstract
As climate change increases vegetation combustibility,
humans are impacted by wildfires through loss of lives
and property, leading to an increased emphasis on prescribed
burning practices to reduce hazards. A key and
pervading concept accepted by most environmental
managers is that combustible ecosystems have traditionally
burnt because plants are fire adapted. In this
opinion article, we explore the concept of plant traits
adapted to fire in Mediterranean climates. In the light of
major threats to biodiversity conservation, we recommend
caution in deliberately increasing fire frequencies
if ecosystem degradation and plant extinctions are to be
averted as a result of the practice.
The Paper's Conclusion
Our review of the literature suggests that traits commonly
accepted as 'fire adaptations' of Mediterranean-climate
plants have more complex origins and that environmental
factors other than frequent fire have promoted their evolution
[97]. Traits such as resprouting, serotiny, physical
dormancy, facultative post-fire flowering and smoke-induced
germination can all enhance survivorship and fitness
under certain fire regimes, but these should be considered as
exaptations rather than adaptations (Table 1). This selective
advantage is readily negated, however, in plant communities
in which fires occur with a frequency higher than
the time taken to flower and set seed for the slowest-maturing
species in that community. The impact of fires on
communities is also a function of their intensity and the
season in which they occur, both of which can override any
inherent advantages flowing from morphological and physiological
exaptations. Climate change, with increasing temperatures
and declining rainfall predicted in Mediterranean
biomes in the coming decades, is likely to exacerbate the
current loss of biodiversity in these regions and will present
a major challenge for environmental managers also charged
with protecting human life and property [98]. We question
the widespread assumption that Mediterranean-ecosystem species
are adapted to fire and suggest that caution is
required in the use of frequent prescribed burning if ecosystem
degradation and plant extinctions are to be averted as a
result of the practice.
Kind regards,
Stephen
Dr Stephen Ambrose
Ryde NSW
===============================
To unsubscribe from this mailing list,
send the message:
unsubscribe
(in the body of the message, with no Subject line)
to:
http://birding-aus.org
===============================
|
