J G Pausas

Publications (2)13.29 Total impact

• Article: Fire and plant evolution

  J G Pausas, D W Schwilk
  New Phytologist 01/2012; 193:301-303. · 6.64 Impact Factor
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  Available from: csic.es

  Article: Fire and plant evolution

  J.G. Pausas, D.W. Schwilk
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  ABSTRACT: Throughout much of the history of ecological science, wildfires were viewed as disasters that destroyed ecosystems. Currently, however, most scientists and managers have overcome this short-sighted view and now consider fires as ecological processes that influence structure and function in many ecosystems worldwide. Despite this, there remain several outstanding controversies regarding the role of fire. One area of research and controversy is the potential of plant traits to result in feedback effects on fire regime (e.g. Bond & Midgley, 1995; Schwilk & Caprio, 2011). There is increasing recognition that wildfires are old phenomena on the Earth as there is charcoal evidence during the whole history of terrestrial plants (Glasspool et al., 2004). In addition, past periods with high atmospheric oxygen concentration made vegetation highly flammable even in wet conditions (Belcher et al., 2010; Glasspool & Scott, 2010). Consequently, vegetation– fire feedbacks may have had major effects on past vegetation and even on biome shifts. For instance, fire may have favored the expansion of angiosperms during the Cretaceous (Bond & Scott, 2010), a time with high concentrations of O 2 (possibly exceeding current values by 25%). Similarly, the expansion of C 4 grasses during the Miocene was favored by fire in extensive seasonally dry areas (Keeley & Rundel, 2005). These studies point to the increasing recognition that fire has been an ancient process on the Earth (Pausas & Keeley, 2009). However, the role of fire as an evolutionary force shaping plant adaptations has remained controversial (Keeley et al., 2011). '… in many fire-prone ecosystems alternative vegetation types with quite different flammabilities co-exist on landscapes' During the recent Mediterranean Ecosystems (MEDECOS) XII conference a special session focused on compiling evidence of fire as an evolutionary process shaping plant traits took place (i.e. fire adaptations). The session benefited from an initial presenta-tion by William Bond (University of Cape Town, South Africa) who provided an overview on the role of fire in biome distribu-tion, with new evidence on the link between fire regime and the Cretaceous expansion of angiosperms (Bond & Scott, 2010). Bond emphasized the feedback role of vegetation on fire regime and pointed out that in many fire-prone ecosystems alternative vegetation types with quite different flammabilities co-exist on landscapes ('open' and flammable vs 'closed' nonflammable communities). These community types often represent groups of taxa with distinct life-histories and phylogenetic origins. Bond pointed out that the size and dynamics of these co-existing patches has been changing during the history in response to changes in fire regime and O 2 and CO 2 atmospheric concentra-tion (with low CO 2 and high fire activity favoring open ecosystems and with high CO 2 and low fire favoring closed eco-systems). Consequently, vegetation has been shaped during the evolutionary history by complex atmospheric processes modifying resource allocation and flammability.
  New Phytologist 01/2012; 93:301-303. · 6.64 Impact Factor