Advances in understanding the influence of fire on the ecology and evolution of plants: a tribute to Peter J. Clarke
Plant Ecol
Advances in understanding the influence of fire on the ecology and evolution of plants: a tribute to Peter J. Clarke
Michael J. Lawes Ross A. Bradstock 0 1 2 3
. David A. Keith . 0 1 2 3
0 D. A. Keith NSW Office of Environment and Heritage , Hurstville, NSW 2220 , Australia
1 D. A. Keith Centre for Ecosystem Sciences, School of Biology, Earth and Environmental Sciences, University of New South Wales , Sydney, NSW 2052 , Australia
2 M. J. Lawes (&) Research Institute for the Environment and Livelihoods, Charles Darwin University , Darwin, NT 0909 , Australia
3 R. A. Bradstock Centre for Environmental Risk Management of Bushfires, Centre for Sustainable Ecosystem Solutions, University of Wollongong , Wollongong, NSW 2522 , Australia
In this special issue of Plant Ecology celebrating the research contributions of the late Peter J. Clarke, we review advances in understanding of interactions between fire and vegetation, and the role of these interactions in shaping the evolution of plant species. The research presented here reviews the measurement of fire severity and plant responses to it, particularly through resistance traits such as thick bark, and resilience traits such as regenerative organs and fire-cued recruitment. It explores genetic and ecological evidence for evolutionary hypotheses that provide insights into associations among plant traits and the causes of their non-random distribution across fireprone landscapes. At these larger scales, the advances include new evidence for existence of fire-mediated alternative stable states and improved understanding of how ecological responses to fire might change under future climates. The diversity of subjects and scales of ecological organisation addressed in this collection of papers reflect the breadth and depth of Peter Clarke's legacy in fire ecology.
Fire ecology; Resilience traits; Resistance traits; Resprouting; Bark thickness; Alternative stable states; Life-histories; Serotiny; Climate change; Fire severity; Post-fire recruitment
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Fire regimes affect long-term vegetation dynamics,
taxon extinction risks, the carbon cycle and other
ecosystem processes (Clarke et al. 2010b) and shape
global biomes (Chuvieco et al. 2008; Archibald et al.
2013; Pausas and Ribeiro 2013). Knowledge of fire
ecology is thus fundamental to ecosystem
management (Lawes and Clarke 2011). This knowledge is
vital given the predicted increase in fire weather under
climate change in many ecosystems (Archibald et al.
2010; Bradstock 2010; Clarke et al. 2011; Little et al.
2012; Clarke et al. 2013a). This special issue of Plant
Ecology is dedicated to Peter J. Clarke who made
diverse contributions to ecological and evolutionary
responses of plants to fire. The research papers in this
special issue have been contributed by Peter’s
colleagues and in many instances co-authored by Peter.
They reflect the breadth and depth of his contribution
to the field.
Understanding and characterising fire regimes
Measuring and assessing the effects of severe fires
Characterising fire regimes and determining how
typical fire regimes affect the composition and
ecology of different plant communities (Murphy et al.
2013) lies at the heart of fire ecology. Much of Peter’s
early work focused on characterising and measuring
the attributes of fire regimes and consequent habitat
associations (Clarke 2002a, b; Clarke and Knox 2002;
Campbell and Clarke 2006; Knox and Clarke 2006;
Nano and Clarke 2008; Knox and Clarke 2011, 2012;
Clarke and Lawes 2013). Here, Knox and Clarke
(2016; this issue) examine the spatial complexities of
fire severity and explore the relationships between
common methods of measuring fire severity and their
utility in predicting the effects of fire severity on plant
ecological processes. Fire severity at the canopy level,
understorey level and below-ground were not strongly
coupled and Knox and Clarke (2016) recommend that
fire severity should be measured in all three strata to
determine the overall fire severity at a site.
Variations in fire intensity, as commonly estimated
via severity, can have long-term compositional and
structural consequences. For example in the mixed
Eucalyptus–Callitris forest in southeastern Australia,
Denham et al. (2016; this issue) showed how
alternative structural states resulted from the responses of
codominant non-resprouting conifers (Callitris spp.) and
resprouting Eucalyptus spp. to contrasting burn
severities. Under high-severity fires (i.e. high levels of
crown scorch and consumption), the post-fire stature
of these forests was reduced because resprouting
Eucalyptus spp. were top-killed (i.e. resprouting was
from basal lignotubers) and regeneration of Callitris
spp. after high mortality was confined to seedlings. By
contrast, low severity fires caused less structural
change due to epicormic resprouting and high levels
of survival due to thick bark, respectively, in these two
groups. Denham et al. (2016) estimated that recovery
of mi (...truncated)