Ulex born to burn
Recurrent fires are a strong evolutionary pressure shaping plants [1,2]. It has been hypothesized that in fire prone-ecosystems, natural selection has favoured the development of traits that enhance flammability . Consistent with this idea, in a recent study  we found that Ulex parviflorus (Fabaceae) populations that inhabit in recurrently burn areas (HiFi populations) are more flammable than populations of this species growing in old-fields where the recruitment was independent of fire (NoFi populations). That is, HiFi plants ignite quicker, burn slower, release more heat and have higher bulk density than NoFi plants. Thus, it appears that repeated fires select for individuals with higher flammability, and thus driving trait divergence among populations living in different fire regimes. These results provide some field support for the ‘kill thy neighbour’ hypothesis , but they also highlighted the need for heritability studies to unambiguously demonstrate natural selection driven by fire. This study together with other studies recently commented in this blog [5, 6] are placing flammability as a fundamental trait in plant evolution.
Figure: Flammability experiments using an epiradiator .
 Bond, W. J. and J. J. Midgley. 1995. Kill thy neighbour: an individualistic argument for the evolution of flammability. Oikos 73:79-85.
 Pausas JG. 2011. Australia born-to-burn: a phylogenetic approach. jgpausas.blogs.uv.es, 18/March/2011 [link]
 Pausas JG. 2011. Fire and evolution: Cretaceous fires and the spread of angiosperms. jgpausas.blogs.uv.es, 9/Sept/2011 [link]